Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare this is a write operation (readOnlyHint=false) and non-destructive (destructiveHint=false). The description adds no additional behavioral context, such as how duplicates are handled, whether existing contacts are updated, or any rate limits. The idempotentHint=true suggests repeated calls with the same email may not duplicate, but the description doesn't clarify this behavior, which could be important for an agent deciding how to invoke it.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, concise sentence with no redundant words or filler. It immediately states the action and object, making it easy for an agent to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity, a single-parameter schema, and annotations that cover safety and idempotency, the description is minimally viable. However, it lacks any mention of related tools, expected outcomes, or behavioral nuances, so an agent has no guidance beyond the raw definition and schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with every parameter and nested property described in the input schema itself. The description adds no parameter-level detail, so with fully self-documenting schema, the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Create new contacts in your SendGrid account' clearly states the verb (create), the resource (contacts), and the scope (SendGrid account). It is unambiguous about what the tool does, though it doesn't explicitly differentiate itself from the sibling create_contact_with_lists, which is a neighboring variation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to use this tool versus alternatives such as create_contact_with_lists or update_contact. There is no mention of prerequisites, complementary tools, or exclusions, so an agent would have to infer usage context from the name alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already provide the key behavioral signals: readOnlyHint=false, destructiveHint=false, and idempotentHint=true. The description restates the core mutation (create and assign lists) without adding extra behavioral context such as duplicate handling, list validation, or partial-failure semantics. There is no contradiction between the description and the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single efficient sentence with no filler. The primary action 'create new contacts' is front-loaded, and the list assignment is immediately clear. This is appropriately concise for scanning during tool selection.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description plus the rich schema covers the essential information needed to invoke the tool: required contacts, optional fields, and list_ids. However, for a mutating tool with no output schema, it leaves edge-case behavior unstated—such as what happens if a contact already exists, if a list_id is invalid, or how partial failures are handled. The idempotentHint annotation helps but the description itself remains minimal.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with both contacts and list_ids fully described in the input schema. The description does not add parameter-level meaning beyond what the schema already provides. Since the schema carries the semantic burden, the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Create new contacts and assign them to specific email lists.' This clearly distinguishes it from sibling create_contact, which does not mention list assignment, and from list-management or removal tools. The plural 'contacts' and 'specific email lists' also signal the intended scope of the operation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no when-to-use guidance or explicit alternatives. It never says to use this tool instead of create_contact when list assignment is needed, nor does it mention when not to use it (e.g., for contacts without lists). An agent must infer the usage context from the tool name and sibling list rather than from the description.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare this is a write operation (readOnlyHint=false), not destructive, and not idempotent. The description adds the 'for contacts' scope but no extra behavioral context such as uniqueness, side effects on existing contacts, or permission requirements. It does not contradict the annotations, so a middle score is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence that conveys action, resource, and scope with no redundant wording. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a low-complexity two-parameter create with full schema coverage and annotations describing the write/non-destructive/non-idempotent nature, the description plus structured data is enough for correct invocation. It does not document return values or duplicate handling, but these are not essential for a basic create call.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%: the schema documents both the required name and field_type, including the allowed enum values Text/Number/Date. The description adds no additional parameter semantics, so the baseline for fully covered schema applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific action ('Create'), a specific resource ('custom field'), and a scope ('for contacts'). This clearly distinguishes it from sibling tools like update_custom_field, delete_custom_field, and list_custom_fields, and from create_contact, without requiring schema inspection.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance about when this tool should be chosen over the sibling custom-field tools, nor any note about prerequisites such as whether custom fields can be created once, are optional, or affect contact forms. The context is implied by the action verb, but no explicit when/when-not guidance is given.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate this is a non-read-only, non-idempotent operation. The description adds no behavioral context beyond what annotations and the action word 'Create' already convey, such as return values, uniqueness behavior, or side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is one concise sentence with no wasted words. It front-loads the primary purpose and is appropriately sized for a single-parameter creation tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple create operation with one required parameter and annotations covering the fundamental behavioral hints, the description is mostly sufficient. It could mention what the operation returns, but the absence of an output schema and the simplicity of the tool make this a minor gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and the schema already documents the 'name' parameter. The description adds no additional parameter-level meaning, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: 'Create a new email list', scoped to the SendGrid account. It clearly differentiates from sibling tools like update_email_list, delete_email_list, and list_email_lists by naming the create action and the exact resource.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives, nor does it mention any preconditions or exclusions. It only restates the core action without explaining how it relates to sibling tools such as create_contact_with_lists or list_email_lists.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With all annotations set to false, the description carries the behavioral disclosure burden. The 'in one step' phrase usefully implies an atomic create-template-plus-initial-version operation, which is a key behavior given the required version_name param. However, it does not explicitly state that a version is also created, nor mention side effects, idempotency, or failure modes, leaving gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single scannable sentence that front-loads the action ('Create a new template with HTML content in one step') and then adds the use case. No filler, no repetition of the title, and every clause adds information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description is adequate for a create tool with fully documented params, but it leaves some context implicit: that this operation also creates an initial version, how duplicates or naming conflicts behave, and what the response will be (no output schema). For a tool sitting among many template and version siblings, a bit more explicit context would help.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so param meaning is fully documented in the schema. The description adds only a general 'HTML content' mention and the AI-design use case, but no per-parameter insight beyond what the schema already gives. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states a specific action ('Create a new template with HTML content') and resource ('new template'), and it adds a distinctive 'in one step' qualifier that hints at what separates it from sibling create_template or create_template_version. However, the differentiation is not fully explicit since it doesn't name or contrast with those siblings directly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'perfect for AI-generated designs' provides a clear use context: use this when you have complete HTML content ready to be turned into a template in a single call. It does not explicitly state when not to use it or list alternatives, but the context is reasonably clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations are limited to readOnlyHint=false and destructiveHint=false, so the description carries the burden of behavioral disclosure, but 'Create a new sender identity' adds nothing. An agent learns nothing about whether duplicate nicknames are rejected, whether sender identities require verification before use, whether the operation is idempotent (idempotentHint=false), or what side effects occur. No contradiction: the write action is consistent with readOnlyHint=false.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single six-word sentence with no wasted words, front-loaded with the action verb. However, for a tool with 8 required parameters — including two nested objects — and no output schema, this brevity is arguably under-specification rather than disciplined conciseness. It earns high marks for economy but not for appropriate sizing.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is non-trivial: 8 required parameters, nested from/reply_to objects, no output schema, and no idempotence guarantee. The description does not explain what the tool returns on success, how failures surface, whether duplicate senders are allowed, or how the created identity relates to send_mail. There is no output schema to fill this gap, so the description is materially incomplete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 75%, near the threshold where the schema carries the explanatory load. The properties all have short descriptions ('ZIP code', 'City', 'Nickname for the sender'), though most are tautological. The description's 'sender identity' phrasing gently hints that the assembled fields (from, reply_to, postal address) form an identity, but it adds little meaning beyond the schema itself.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Create a new sender identity.' The purpose is unambiguous and the verb distinguishes it from the related siblings list_senders and delete_sender. However, it is very close to restating the title 'Create Sender' — the only added semantic is the word 'identity' — and it provides no detail about what constitutes a sender identity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives zero guidance on when to use this tool versus alternatives. With over 50 siblings including list_senders and delete_sender, and adjacent tools like create_email_list and create_contact, an agent receives no signal about the sender-identity use case or when not to call this tool. It is not misleading, but it provides no usage direction.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations provide no distinctive behavioral hints beyond indicating this is a mutating, non-idempotent operation. The description adds no context about side effects, permissions, duplicate handling, or whether existing templates are overwritten. Since this is a create operation with no safety annotations, the description should disclose more about what 'create' entails in this system.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single, direct sentence with no filler. The core action is front-loaded and the qualifiers add specificity without bloating the description. It could earn a 5 if it also packed in usage guidance, but as a concise statement it is effective.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema and several closely related sibling tools, the description is under-specified. It does not explain what makes a template 'dynamic' or 'transactional', whether the operation is scoped to a particular workspace, or how it differs from create_html_template. An agent would need to inspect other tool schemas to confidently select and invoke this one.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already provides descriptions for both parameters with 100% coverage, so the baseline is 3. The description's 'dynamic' qualifier loosely aligns with the generation parameter default but does not add meaningful detail about how name or generation are used, nor does it clarify the significance of 'legacy' vs 'dynamic'.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description identifies a clear verb ('Create') and resource ('template'), adding the qualifiers 'dynamic' and 'transactional' which distinguish it from generic template creation. However, it does not explain what a dynamic transactional template is, and 'dynamic' partially overlaps with the generation parameter's enum value, so the reader is left to infer the full scope.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus closely related siblings such as create_html_template or create_template_version. The qualifier 'dynamic' hints at a distinction, but no explicit selection criteria or alternatives are mentioned, leaving the agent to guess which template creation path is appropriate.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only indicate non-read-only, non-idempotent, non-destructive behavior. The description adds little beyond the creation action, omitting important behavioral context such as the effect of 'active' on the template's current version, auto-generation of plain content, or what response is returned. This is a meaningful gap for a mutation tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no filler. However, 'settings' is vague and could be more explicit, which slightly reduces structural payoff despite the overall compactness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 8 parameters and no output schema, the description is minimal but not wholly inadequate because the schema documents each field. Still, it lacks context about versioning semantics, how active versions are managed, and what the caller should expect after creation, leaving notable gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so parameters are individually documented in the schema. The description's phrase 'HTML content and settings' adds no specific parameter meaning beyond that, and it does not help disambiguate nuanced fields like active, test_data, or generate_plain_content.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Description states a specific verb and resource: 'Create a new version of a template'. This clearly distinguishes it from sibling tools like create_template or update_template_version, and it names the core payload ('HTML content and settings').

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the tool is for adding a version to an existing template, but it gives no explicit when-to-use guidance or exclusions. It does not contrast with create_template or update_template_version, so the agent must infer when this tool is preferred.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already flag destructiveHint=true and readOnlyHint=false, but the description adds meaningful behavioral context by stating the deletion is permanent and cannot be undone. This goes beyond the structured hints and gives the agent a stronger basis for warning about side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences with no filler. The core action is front-loaded ('Permanently delete a marketing automation'), and the second sentence adds an important warning without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter destructive action with comprehensive annotations and full schema coverage, the description is sufficient for an agent to select and invoke the tool correctly. The irreversibility warning compensates for the absence of an output schema by setting expectations about the action's consequences.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema fully documents the only parameter, automation_id, as 'The automation ID to delete,' so schema coverage is 100%. The description does not add extra parameter-level detail, but the baseline of 3 applies because the schema already carries the semantic weight.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses the specific verb 'delete' and identifies the exact resource, 'marketing automation,' making the operation unambiguous. The permanence qualifier and the irreversibility warning distinguish it from sibling tools like update_automation_settings or get_automation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use the tool: when the intent is to permanently remove a marketing automation. However, it provides no explicit alternatives, exclusions, or conditions, such as 'use update_automation_settings to modify instead of deleting,' so guidance is mostly implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=false and destructiveHint=true, and the description aligns by stating 'Delete.' It adds the 'by IDs' scoping but does not disclose irreversibility, cascading effects, or behavior on nonexistent IDs. The description does not contradict the annotations, so a neutral score is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise, front-loaded, and free of filler. It is slightly redundant with the title, but for a one-parameter tool this brevity is still appropriate.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple, one-parameter destructive operation, the description plus annotations and full schema coverage provide enough information for an agent to select and invoke the tool correctly. It does not describe the response format, but that is a minor gap given the tool's simplicity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%; the single parameter contact_ids is already described as 'Array of contact IDs to delete.' The description's 'by IDs' reinforces that meaning but adds no substantive information beyond the schema, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Delete'), identifies the resource ('contacts'), and specifies selection by IDs, making the operation clear. It is semantically distinguishable from related sibling tools like create_contact or get_contact, though it does not explicitly differentiate itself from remove_contact_from_lists.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance about when to use this tool versus alternatives such as remove_contact_from_lists or update_contact, nor any mention of prerequisites or caveats. The only usage signal is implied by the name and description, not explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description does not contradict the annotations, but it also adds no behavioral context beyond them. For a destructive operation, it omits useful details such as whether deletion is permanent or whether it affects contacts/data that use the custom field. The idempotent and destructive hints carry the disclosure burden alone.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no filler or repetition. Every word contributes to identifying the operation and the target resource.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter delete tool, the core invocation details are present: action, resource, and required field_id. However, the description omits the consequences of deletion and any guidance on how to find the field_id, so it is not fully complete for an agent operating without prior context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%: field_id is documented as 'ID of the custom field to delete'. The description adds no further nuance, but none is required because the single parameter is fully explained by the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Delete') and names a precise resource ('custom field definition'), which clearly distinguishes it from sibling tools like create_custom_field, update_custom_field, and list_custom_fields. It is immediately obvious what action an agent would take with this tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to choose this tool instead of create_custom_field or update_custom_field, nor does it mention prerequisites such as how to obtain the field_id (e.g., via list_custom_fields). An agent must infer usage solely from the tool name and inline schema.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already signal destructiveHint=true, readOnlyHint=false, and idempotentHint=true, so the safety profile is known. The description adds only that the list must be existing but does not disclose side effects (e.g., whether associated contacts are affected) or failure behavior. No contradiction with annotations exists.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no redundant wording. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter delete operation with annotations covering destructiveness and idempotence, the description and schema are largely sufficient for an agent to invoke it correctly. It could mention response/side-effect expectations, but the low complexity makes the omission non-critical.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 100% coverage: list_id is described as 'ID of the email list to delete.' The description adds no further parameter meaning, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific imperative verb ('Delete') and a concrete resource ('an existing email list from your SendGrid account'), so an agent immediately knows the operation. It is clearly distinct from sibling tools like create_email_list, update_email_list, or list_email_lists.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The imperative phrasing implies the obvious use case: delete a list. However, it gives no explicit when-not-to-use guidance or alternatives, such as distinguishing deleting the list from removing contacts via remove_contact_from_lists or deleting individual contacts with delete_contact. The context is clear but the exclusions are left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare destructiveHint=true and idempotentHint=true, so the destructive nature is disclosed. The description adds no behavioral detail beyond restating 'Delete', such as whether deletion is permanent, cascading, or requires special permissions. It provides no value beyond the structured annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is only five words and gets directly to the point with no filler or redundant phrases. It is appropriately minimal for a simple delete operation and every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter deletion tool with destructiveHint and idempotentHint annotations, the description is mostly sufficient. It clearly identifies the operation and the required parameter, and no output schema is expected. It does not explain consequences or return behavior, but the annotations cover the critical safety aspects.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The single parameter segment_id is fully described in the schema with 'ID of the segment to delete', which is clear. The tool description adds no additional parameter semantics. Since schema description coverage is 100%, the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action (Delete) and the resource (an existing segment), making the tool's purpose immediately understandable. It distinguishes itself from sibling tools like update_segment or list_segments by naming the delete operation. However, it is very close to the tool name and title, adding only the qualifier 'existing'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied: you use this tool when you need to remove an existing segment. There is no explicit guidance about when not to use it or mention of alternatives such as update_segment for modifying a segment. The context is clear enough for a simple delete operation, but no explicit routing is provided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds the 'verified' qualifier, which clarifies the resource scope, but does not disclose irreversibility, permissions, or downstream effects. With annotations present, this is adequate but not rich.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence with no filler or redundant phrasing. Every word contributes to the meaning, and the key action is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter deletion tool with destructive and idempotent annotations, the description covers the essential behavior. An output schema is not present, but for a delete action the return value is usually not critical. The only minor gap is lack of explicit usage guidance, but this is a simple tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and the sender_id parameter is already described as 'ID of the sender identity to delete'. The description adds no additional parameter-level meaning, so the baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Delete') and a concrete resource ('verified sender identity'), making the action unmistakable. It clearly distinguishes this tool from other delete_* siblings like delete_email_list or delete_template.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The usage context is implied: use this when a verified sender identity needs to be removed. However, there is no explicit guidance about when not to use it or how it relates to create_sender or list_senders, so the agent must infer the routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark this as destructive and idempotent; the description adds specific behavioral context by disclosing the cascade effect: all versions are deleted along with the template. It does not mention irreversibility or permissions, but this is adequately covered by the destructive annotation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One short sentence with the verb and resource front-loaded, and every word adds meaningful information. There is no fluff or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter delete operation with destructive and idempotent annotations already provided, this description is complete. It tells the agent what is deleted and the scope of deletion, and no output schema is expected for a delete operation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and template_id is already described as 'ID of the template to delete'. The description adds no additional parameter-level meaning, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Delete') and resource ('template') and adds the important scope detail 'and all its versions'. This clearly distinguishes it from the sibling delete_template_version, which targets only a single version.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'and all its versions' gives clear context that this tool is for full template deletion, implying that version-specific deletion belongs elsewhere. However, it does not explicitly name the alternative or provide a when-not-to-use condition, so it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description aligns with the destructiveHint=true annotation and adds that only a specific version is affected, not the template itself. It does not add deeper behavioral context such as reversibility, permissions, or consequences for the parent template, but the annotations already cover destructive intent and idempotency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence with no filler. It front-loads the action and the specific resource, making it immediately actionable.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple two-string-parameter destructive operation, the description plus annotations and full schema coverage are largely sufficient. It lacks explicit guidance on alternatives, but the task is simple enough that an agent can invoke it confidently from the given information.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and both parameters, template_id and version_id, already have clear schema descriptions. The tool description does not add any additional parameter meaning beyond what the schema already provides, so the baseline score applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb, ‘delete’, a clear resource, ‘a specific version of a template’, and distinguishes this from deleting the entire template. The sibling tool list includes delete_template, so the version-specific wording helps disambiguate.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase ‘a specific version of a template’ clearly implies this tool is for version-scoped deletion, and the sibling list includes delete_template for the alternative. However, it does not explicitly state when not to use this tool or direct the agent to delete_template for whole-template deletion.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds that the response includes all steps and settings, but does not disclose return shape, missing-ID behavior, or other quirks. That is acceptable but minimal.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Single sentence, front-loaded with verb and resource, with no redundant filler. The phrase 'including all steps and settings' earns its place by specifying output scope.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple getter with one required parameter and safety annotations, the description plus schema covers the essentials: what to pass, that the operation is read-only, and what comes back. Missing not-found behavior and output format are minor gaps given the low complexity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% — automation_id is fully described as 'The automation ID to retrieve'. The description adds no parameter-level detail beyond this, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific read operation ('Get detailed information') on a specific resource ('a specific automation') and clarifies the scope ('including all steps and settings'). This distinguishes it from mutation siblings like update_automation_settings and from list_automations, though it doesn't explicitly name an alternative.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage when an agent needs full details for one automation, but gives no explicit when/when-not guidance or alternative routing. It doesn't say to use list_automations when an ID is unknown, so some inference is required.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark the operation as read-only, idempotent, and non-destructive, and the description adds the meaningful behavioral constraint that data is available only for the previous 13 months. It does not describe return shape or error behavior, but with annotations covering the safety profile, this is sufficient context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is one concise sentence with no redundant wording. The core action and resource are front-loaded, and the 13-month limitation is included as a brief, important caveat in parentheses.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only stats tool with four well-documented parameters and safety annotations, the description captures the essential constraint an agent needs to know: the 13-month limit. No output schema exists, so return structure is not described, but the core invocation context is adequately covered.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% description coverage, so every parameter is already explained. The description adds only the high-level notion of 'specific categories' and the 13-month data availability, which is useful context but does not add parameter-level detail beyond what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description identifies a specific action ('Retrieve') and a specific resource ('email statistics for specific categories'), which distinguishes it from sibling tools like get_global_stats or get_stats_by_country. The title reinforces the same resource, so there is no ambiguity about what this tool operates on.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies this tool is for category-level email statistics and notes the 13-month availability window, but it does not explicitly state when to choose this instead of get_global_stats or get_stats_by_browser. There are no named alternatives or exclusions, so guidance is only inferable from the resource name and sibling list.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is established. The description adds little behavioral detail beyond 'detailed information' and does not mention edge cases, permissions, or return format, but it does not contradict the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single short sentence with no filler. It front-loads the operation and the key selection criterion, making it easy for an agent to parse quickly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only get-by-ID tool with one required parameter and clear annotations, the description is nearly sufficient. It could be more complete by explicitly noting that list_contacts or search_contacts should be used for non-ID lookups, and by clarifying what 'detailed information' includes since there is no output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so contact_id is already fully documented. The description's 'by ID' aligns with the parameter but adds no new constraints, formats, or relationship details, so it stays at the baseline for high schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb+resource pair ('Get ... contact') and identifies the selector ('by ID'), which clearly distinguishes it from sibling list/search tools like list_contacts and search_contacts. The operation is unambiguous for an agent selecting a tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'a specific contact by ID' clearly signals that this tool is for retrieving one known contact, not for listing or searching. It does not explicitly name alternatives or exclusion conditions, but the intended usage context is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no behavior beyond 'Retrieve', such as response shape, aggregation semantics, or potential size of results. It does not contradict the annotations, but it also does not add meaningful behavioral context beyond them.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single direct sentence with no filler. It front-loads the verb and resource, and every word contributes to the meaning. It is appropriately concise for a straightforward read-only statistics tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple, the schema is complete, and annotations cover safety, so the description is minimally adequate for invoking the tool. However, there is no output schema and the description does not clarify what metrics are returned or how this relates to the many sibling statistics tools, leaving some ambiguity for an AI agent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% description coverage for all three parameters, including formats, defaults, and the enum for aggregated_by. The description adds no parameter-level detail, but the schema already carries the full semantic burden, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Retrieve') and a clear resource ('global email statistics for your SendGrid account'). It distinguishes from sibling stats tools through the word 'global', implying account-wide scope as opposed to per-browser, per-country, per-category, or per-subuser stats, but it does not explicitly compare against those alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'global email statistics' implies this tool is for account-wide aggregates rather than dimension-specific breakdowns, but the description never explicitly states when to use this tool versus siblings like get_stats_by_country, get_category_stats, or get_subuser_stats. Guidance is therefore implied rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is clear. The description adds no behavioral detail beyond the resource being fetched, such as return format or ordering, but it does not contradict the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One short sentence with no filler or repetition. The key information is front-loaded and every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter, read-only lookup with strong annotations and no close sibling competitors, the description is sufficient for an agent to invoke it correctly. The absence of an output schema is not a significant gap here because the description names exactly what is returned.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There are zero parameters and schema description coverage is 100%, so there is nothing for the description to add. The default baseline of 4 applies because the schema fully handles the parameter surface.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb (Get) and resource (available permission scopes for API keys), making the tool's function immediately clear. It is also distinct from all sibling tools, none of which deal with permission scopes.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The use case is implied: retrieve the list of valid permission scopes for API keys. However, the description does not explicitly state when to use this tool versus alternatives, nor does it mention any prerequisites or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds that the tool returns 'detailed content and settings' but does not disclose any additional behavioral traits such as error handling, field coverage, or potential edge cases.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, focused sentence with no redundant words or filler. It front-loads the main action and resource without requiring extra reading.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple retrieval tool with one required parameter and helpful annotations, the description is nearly complete. The only minor gap is that it does not enumerate the returned 'content and settings' fields, and there is no output schema to provide that detail.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% description coverage and fully documents singlesend_id as 'The single send ID to retrieve.' The tool description adds no further parameter-level meaning, so the schema carries the semantic weight as expected.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Get') and resource ('single send campaign'), and further clarifies the scope as 'detailed content and settings.' This clearly distinguishes it from sibling tools that handle templates, stats, contacts, or send operations.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the tool is for retrieving a specific single send campaign by ID, but it does not explicitly state when to use it over alternatives or mention any exclusions. Usage context is inferable but not articulated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so no safety contradiction exists. The description adds meaningful behavioral context beyond annotations by explicitly stating that only clicks and unique_clicks metrics are available, which prevents the agent from expecting open or send metrics.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences with no redundant filler. The primary action and grouping are front-loaded, and the critical metric limitation is stated immediately after.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only stats retrieval tool, the description plus fully documented schema cover the essential information: what is returned, how to filter, how to paginate, and how to aggregate. It is slightly incomplete in not situating the tool among its sibling stats tools, but this is a minor gap given the schema richness and annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema fully documents all six parameters, including defaults, formats, and pagination semantics. The description does not add parameter-specific meaning, but it also does not need to because the schema already carries the burden.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Retrieve'), a clear resource ('email statistics'), and the grouping dimension ('browser type'). This distinguishes it from sibling stats tools like get_stats_by_client_type and get_stats_by_country, and it also narrows the available metrics to clicks and unique_clicks.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description clearly implies use when browser-level click statistics are needed, but it provides no explicit guidance about when to prefer this tool over the many sibling stats tools. It does not mention alternatives or exclusion criteria such as 'for device-level stats, use get_stats_by_device_type'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already cover read-only, idempotent, and non-destructive behavior. The description adds meaningful behavioral constraints beyond those: only opens and unique_opens metrics are available, and filtering/pagination are unsupported. This helps set agent expectations without contradicting the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three short sentences with no filler. Each sentence adds distinct value: purpose, metric limitations, and endpoint limitations. It is front-loaded and easy to scan.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only stats endpoint, the description is mostly complete: it states the grouping, the available metrics, and the lack of filtering/pagination. Since there is no output schema, the metric detail partially compensates. It could be slightly richer by mentioning the response shape, but the core context is sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the parameters are fully documented in the schema itself. The description does not add parameter-specific details beyond what the schema already provides, but it does give useful context about the overall endpoint behavior. Baseline 3 is appropriate here.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Retrieve') and resource ('email statistics grouped by email client type'), explicitly naming the grouping dimensions (desktop, mobile, webmail). It also clarifies which metrics are available, making the tool's purpose unambiguous and distinct from other stats-related siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description clearly implies when to use this tool: whenever email statistics are needed by client type. It also provides useful exclusions by stating that filtering and pagination are not supported. However, it does not explicitly name alternative sibling tools or spell out when not to use this one.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds behavioral constraints beyond annotations: the restricted metric set and the absence of a state/province filter. This helps the agent set expectations, though it stops short of describing the exact response shape or pagination behavior, which is acceptable given the schema covers the parameters.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with no redundant words. The primary action and grouping dimension are front-loaded, followed by a compact statement of metric availability and filtering constraints. Every sentence contributes value and the description is appropriately sized for a read-only stats tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a six-parameter tool with no output schema, the description covers the essential aspects: purpose, grouping level, supported metrics, and filtering limitation. It does not spell out response structure or pagination defaults, but those are either implied by the grouping description or documented in the schema. The core usage context is complete enough for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds minimal parameter-specific meaning: it confirms the country filter exists and implies date-range grouping, but it does not elaborate on formats, defaults, or how limit/offset interact with the grouping. The schema already carries the heavy lifting for parameter definitions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Retrieve email statistics grouped by country.' It clarifies that only four metrics are available, immediately distinguishing it from sibling stats tools by its grouping dimension. The second sentence reinforces scope with a clear exclusion ('no state/province filter exists'), leaving no ambiguity about what the tool does.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context by stating the grouping is by country and explicitly naming which metrics are available. It also warns that filtering is only by country, which implies the tool is unsuitable for sub-national breakdowns. While it does not name alternative tools or give explicit when-to-use guidance, the context is sufficient for an agent to select it over sibling stats tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotent, and non-destructive behavior, so the description only needs to add context. It adds the meaningful limitation that only opens and unique_opens metrics are available, but does not go into pagination, date-range handling, or response characteristics.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One concise sentence that front-loads the core purpose and then adds the critical metric restriction. No filler or redundant restating of the title.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given that all parameters are fully described in the schema and annotations cover read-only/idempotent behavior, the description covers the key missing piece: which metrics are available. There is no output schema, so the return structure is not described, but the tool is simple enough that this is a minor gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%; every parameter (limit, offset, end_date, start_date, aggregated_by) has its meaning documented in the schema. The description does not add parameter-level detail, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action ('Retrieve email statistics'), the grouping resource ('by device type'), and the exact dimension (desktop, mobile, tablet). It also names the available metrics, which clearly sets it apart from sibling stats tools grouped by browser, country, or mailbox provider.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The context is clear: use this tool when you need email stats segmented by device type. The 'Only opens and unique_opens metrics are available' sentence gives an implicit exclusion, warning the agent away if other metrics are needed, though it does not explicitly name alternative tools.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral context by enumerating the returned metrics and noting the absence of unsubscribes, but does not discuss pagination or response structure beyond what the schema implies.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences with no filler: the first states the core function, the second lists the full metric scope, and the third flags a meaningful omission. Every sentence earns its place and the key purpose is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only stats retrieval with fully documented parameters and clear annotations, the description covers what an agent needs to select and invoke the tool. The lack of an output schema is mitigated by the explicit metric list, though slightly more guidance on when this tool is preferred over sibling stats tools would make it complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so parameters are already fully documented. The description adds context about the grouping and metric set but does not explain any parameter semantics beyond what the input schema provides, matching the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Retrieve') and a clear resource ('email statistics grouped by mailbox provider') with concrete examples. It also differentiates itself from sibling stats tools by being the 'Broadest metric set of all stats breakdowns' and explicitly listing supported metrics.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description makes the grouping dimension explicit and signals when this tool is appropriate through 'Broadest metric set of all stats breakdowns.' It does not explicitly name alternatives or state when not to use it, so it stops short of full exclusion guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds only a vague 'across multiple dimensions' scope and does not disclose any further behavioral traits such as aggregation behavior, time filtering, or response size; still, it does not contradict the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no filler or repetition. It is concise, though somewhat generic and under-specified.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, and the description does not explain what 'multiple dimensions' actually includes or what the returned overview looks like. Given the large set of sibling stats tools, this definition is too thin to let an agent confidently decide whether to call this tool or a more specific stats-by-dimension tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so start_date, end_date, aggregated_by, and include_subusers are already documented in the input schema. The description adds no parameter-level meaning, which keeps this at the baseline rather than higher.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description identifies a clear verb ('get') and resource ('email statistics overview') and adds the qualifier 'across multiple dimensions,' which gives a reasonable sense of what the tool does. However, it does not name or contrast any sibling tools, so an agent cannot easily distinguish it from get_global_stats or get_stats_by_* variants.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'comprehensive overview ... across multiple dimensions' implies this tool is for broad, multi-dimensional email statistics rather than a single-dimension breakdown. But there is no explicit when-to-use/when-not-to-use guidance, no named alternatives, and no indication of how this tool differs from the many other stats tools in the sibling list.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no further behavioral context, such as response shape, pagination, or what happens without data, but it also does not contradict the annotations. That makes a 3 appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no wasted words. It clearly states the verb and target, and every word earns its place relative to the tool's purpose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description carries the burden of explaining what 'email statistics' actually returns. It does not mention metrics, grouping behavior, or date-range implications, leaving an agent to guess whether the response contains counts, rates, or a time series. The schema covers parameters, but the output semantics are underspecified.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description does not add any parameter-specific detail beyond the schema; 'specific subusers' aligns with the subusers parameter but adds no new meaning to start_date, end_date, or aggregated_by.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Retrieve') and resource ('email statistics'), and the qualifier 'specific subusers' distinguishes it from siblings like get_global_stats and the get_stats_by_* breakdown tools. Even the title reinforces the subuser dimension, making the tool's function immediately clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to choose this tool over the many sibling stats tools (e.g., get_global_stats, get_stats_by_country, get_stats_overview). It does not explain that this is the appropriate choice when the user wants per-subuser filtering, nor does it mention any exclusions or alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false). The description adds behavioral context by specifying that all versions are included, which goes beyond the annotations. It does not mention auth or rate limits, but for a simple read operation the annotation coverage lowers the burden.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, concise, grammatically complete sentence with no filler. The key action and the distinctive 'including all versions' scope are front-loaded, making it easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter read-only retrieval with no output schema, the description provides sufficient information to invoke the tool correctly: it identifies the resource, the parameter scope, and the return coverage. It does not detail the exact response structure, but this is a minor gap given the tool's simplicity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and the single parameter template_id is clearly described as the ID of the template to retrieve. The tool description adds no additional parameter-level meaning, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Retrieve'), a clear resource ('details of a specific template'), and a distinguishing scope ('including all versions'). This differentiates it from the sibling get_template_version, which targets a single version, and from list_templates, which lists templates.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the tool is for retrieving a single template with all versions, but it does not explicitly state when to use it over get_template_version or list_templates. There are no exclusions or alternative routing signals, leaving the decision to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already provide readOnlyHint: true, idempotentHint: true, and destructiveHint: false, and the description only restates the retrieval nature without adding behavioral context. It does not mention return format, possible errors, or any side effects, though it does not contradict the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence with no filler. It is front-loaded with the core action and object, but it is slightly too terse to also provide usage differentiation or behavioral detail, so it does not earn a 5.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

This is a simple read-only retrieval tool with two clearly documented parameters and strong annotations, so the description does not need much more. However, it lacks any mention of what 'details' include, and it does not clarify how this relates to similar template tools, leaving some context gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and both parameters have clear descriptions: 'ID of the version to retrieve' and 'ID of the template'. The tool description adds little beyond the schema, but the baseline of 3 is appropriate because the schema already fully documents the parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Retrieve') and a specific resource ('details of a specific template version'), clearly distinguishing this from sibling tools like get_template, update_template_version, and delete_template_version. The inclusion of the word 'version' removes ambiguity about which object is being fetched.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to use this tool versus alternatives such as get_template or list_templates. It does not state prerequisites, exclusions, or conditions that would help an agent choose this tool over a sibling.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safe, non-mutating nature is established. The description adds only the 'all' scope and does not contradict annotations; however, it does not disclose pagination behavior or whether inactive/draft automations are included.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single, front-loaded sentence with no filler. Every word earns its place, and the tool's core purpose is immediately clear.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read-only list with no required parameters, the description is near-sufficient, and the schema covers pagination parameters. However, the 'all' claim is not reconciled with default pagination, and without an output schema the description does not mention what fields or resource types are returned beyond 'automations'.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%: both limit and offset already have descriptions ('Number of results to return', 'Pagination offset'). The tool description contributes no additional parameter meaning, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'List all marketing automations' clearly identifies the verb (list), resource (marketing automations), and scope (all). It is unambiguous versus sibling tools like get_automation, update_automation_settings, and list_single_sends, though it does not explicitly name any alternative or exclusion.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is given on when to choose this tool versus alternatives such as get_automation, list_single_sends, or open_automation_editor. The description simply states the action and never addresses selecting between list tools or retrieving a single automation.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already convey readOnly, idempotent, and non-destructive behavior; the description adds the 50-contact cap, recency selection, sort order, and deprecation of pagination. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with the core behavior front-loaded and the limitation/alternative in the second sentence. No filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter read-only list tool with no output schema, the description gives the essential usage constraints and routes to alternatives. Nothing an agent needs to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With an empty input schema, the baseline is 4, and the description goes further by stating the endpoint truly takes no parameters and explaining why (SendGrid deprecated pagination). This prevents an agent from looking for hidden pagination/query parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('List') and resource ('contacts') with precise constraints: up to 50, most recently uploaded/updated, sorted by email address. This distinguishes it from siblings like list_email_lists, list_segments, and search_contacts.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicity says the endpoint takes no parameters and that SendGrid deprecated pagination, and directs the agent to use search_contacts or export for anything beyond a quick sample. This gives clear when-to-use and when-not-to-use guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, but the description adds no behavioral context beyond that. It does not mention pagination, ordering, authentication requirements, or return shape, so it provides no value beyond the structured annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence with no filler or repetition. It is concise, but it is also slightly under-specified, so it does not reach the highest bar.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a no-parameter read-only tool, the description is minimally adequate, but with no output schema and no behavioral details it leaves gaps around return structure and usage context. It does not fully equip an agent to understand what a successful response will contain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters and 100% schema coverage, so the description does not need to explain any parameter behavior. The baseline of 4 applies because there is nothing for the schema or description to elaborate on.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action ('List') and a specific resource ('custom fields'), making it clear what the tool does. It differentiates from the create/update/delete_custom_field siblings by the explicit read-focused verb, though it does not add scope or output details that would earn a 5.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is given on when to use this tool versus alternatives such as create_custom_field, update_custom_field, or other list_* tools. The intended use is only implied by the name and description, with no exclusions, prerequisites, or alternative routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds the scope 'all' but does not disclose pagination behavior or the effect of page_size, which is relevant for a list tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence with no filler or redundancy. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter, safely annotated list tool, the description is mostly sufficient to invoke correctly. It is slightly incomplete because it does not reconcile 'all' with the page_size pagination parameter or clarify what fields the returned email lists contain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% for the only parameter 'page_size', which includes a default and a clear description. The tool description adds no parameter-level meaning beyond what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states the exact verb and resource: 'List' + 'all email lists'. This clearly distinguishes it from sibling tools that list segments, contacts, templates, senders, or automations, and from create/update/delete_email_list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The intended use is implied by the command itself: use it when you need to list email lists. However, it provides no explicit when-not guidance or comparison to alternatives like list_segments or list_contacts, so the agent receives no routing help.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds that the tool returns all segments and includes parent-list relationship data, which is useful, but it does not mention pagination, ordering, or response structure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single clear sentence with no wasted words. It front-loads the core action and includes the key differentiator about parent list relationships.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter, read-only list operation with annotations covering safety, this description is nearly complete. It explains what is returned, though it could be more explicit about the output representation of segment and list relationships.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool accepts zero parameters and the schema is empty, so the schema fully describes invocation needs. With no parameters to document, a baseline of 4 is appropriate and no additional description is needed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: 'List all segments' and adds a meaningful qualifier 'with their parent list relationships.' This distinguishes it from sibling tools like list_email_lists and segment mutation tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The intended use case is clear: when an agent needs all segments and their list relationships, this tool is the choice. It does not explicitly mention alternatives or when-not-to-use, but the singular purpose and simple scope make the usage context obvious.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the operation as read-only, idempotent, and non-destructive. The description adds behavioral nuance by specifying 'verified' senders and 'all', indicating that unverified senders are not returned and that the listing is comprehensive. This goes beyond annotation coverage.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence with no filler: 'List all verified senders'. It front-loads the verb and object and every word adds meaning.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter, read-only listing tool, the description plus annotations are sufficient. The 'verified' scope is important and captured. The absence of an output schema is acceptable since 'list' implies a collection result, and no safety caveats are missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so schema coverage is 100% by definition and no parameter documentation is needed. Per the baseline for zero-parameter tools, this is fully adequate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('list') and a clearly scoped resource ('verified senders'), making the tool's function unambiguous. It distinguishes itself from sibling tools like create_sender and delete_sender, and from other list_* tools which target different resources (email_lists, segments, contacts, etc.).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description clearly implies when to use this tool: whenever an agent needs to enumerate verified senders. While it doesn't explicitly name alternatives or exclusions, no sibling tool overlaps with listing senders, so the route is clear without explicit guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no additional behavioral context such as pagination behavior, ordering, or how 'all' relates to page_size/page_token, leaving the agent to infer these details from the schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single efficient sentence with no filler. Every word contributes to the meaning, and the key scope word 'all' is included.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

This is a simple list operation with two optional, well-documented parameters and safe annotations, so the description is mostly adequate. However, there is no output schema and the description does not mention that results are paginated or describe the response shape, leaving minor but real gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with page_size and page_token already documented in the input schema. The description adds no param-level meaning, so the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('List') and a specific resource ('all single send campaigns'), which clearly distinguishes it from singular or creator/stats siblings like get_single_send, open_single_send_creator, and open_single_send_stats. An agent can understand exactly what this tool returns.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The tool's purpose is clear, and 'list all' implies it should be used when a collection of single send campaigns is needed rather than a single campaign. However, there is no explicit guidance about when to prefer this tool over alternatives such as get_single_send, and no exclusions or context are provided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds that the listing spans both legacy and dynamic generations, but it doesn't disclose pagination behavior or response structure; it also repeats the schema's generation filter values rather than adding new behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single sentence that front-loads the verb and object and contains no filler. It is an appropriately sized definition for a simple list operation.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a low-complexity read-only list tool with fully documented optional parameters and safety annotations, the description is sufficient for an agent to select and invoke it. It could mention pagination defaults or the return payload, but those are either implicit in list tools or covered by the schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema coverage, the schema already documents page_size and generations. The description doesn't add new parameter details; it merely echoes the 'legacy and dynamic' values that the generations schema description already lists, so it meets the baseline but adds no extra meaning.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with the verb 'Retrieve' and names the resource 'all transactional templates', explicitly scoping to 'legacy and dynamic' generations. This clearly distinguishes it from single-resource siblings like get_template and from mutation tools like create/update/delete_template.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the tool's use—call it to list transactional templates—but offers no explicit guidance about when to prefer it over get_template for a specific template or open_template_editor for editing. No alternatives or exclusions are mentioned.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safe, non-mutating behavior is covered. The description adds that the action opens a browser UI, which is useful context but does not go beyond that. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise at seven words, front-loads the action, and has no redundant filler. Every word contributes to understanding the tool's purpose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a parameterless UI-launching tool, the description is complete. It identifies what to open and the medium (browser), and no return value or additional options are relevant. An agent can correctly invoke this tool based on the description alone.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so the schema is fully coverage with no parameter semantics to explain. The description does not need to add parameter details; the baseline of 4 is appropriate for a parameterless tool.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action (Open), a specific resource (SendGrid automation creator), and the context (in browser). It is clearly distinguishable from siblings like open_single_send_creator and open_automation_editor because it names 'automation creator' explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance about when to use this tool versus alternatives such as open_automation_editor or open_single_send_creator. The description is self-evident about what it does but leaves the choice of tool to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this operation is safe and non-mutating. The description adds little behavioral context beyond the word 'Open', but it does not contradict the annotations. Given the annotations carry most of the safety information, a 3 is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single, front-loaded sentence with no filler. Every word earns its place, and the key constraint ('specific automation') appears immediately.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter tool with strong annotations and full schema coverage, this description is mostly sufficient. The main missing piece is what 'open' actually produces (e.g., a URL, a UI navigation) and explicit sibling differentiation, but these are not critical for invoking the tool with the required automation_id.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so automation_id is already documented in the input schema. The description's 'for a specific automation' aligns with the parameter but does not add format, source, or usage details beyond what the schema provides. This meets the baseline for high schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Open') and resource ('automation editor') and adds 'for a specific automation', which indicates it targets an existing automation rather than creating a new one. It does not explicitly name sibling tools like open_automation_creator, but the 'specific automation' wording is enough to make the basic purpose clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance about when to use this tool versus alternatives such as open_automation_creator or update_automation_settings. The phrase 'for a specific automation' only implies that the automation already exists, but the description never states when this tool should be chosen instead of a related sibling.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish readOnlyHint, idempotentHint, and destructiveHint=false, so the description does not need to repeat those. The phrase 'in browser' adds a useful behavioral detail beyond the annotations, but the description does not mention potential side effects like requiring an existing browser session, authentication, or whether a new tab is opened.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence of seven words, with every word carrying meaning: action ('Open'), context ('SendGrid'), resource ('CSV contact upload page'), and execution environment ('in browser'). It is fully front-loaded and free of redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter, no-output-schema tool with annotations covering safety, the description conveys the essential action and target, making it complete enough to invoke. It stops short of a 5 because it does not explain the workflow context or when to choose this over other open_* tools.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has zero parameters, so the baseline is 4. The description correctly omits parameter details because there are none; there is nothing to compensate for.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly identifies a specific action ('Open') and a unique resource ('SendGrid CSV contact upload page in browser'). This resource is distinct from sibling open_* tools like open_automation_editor or open_single_send_creator, so an agent can tell them apart without inspecting schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives such as open_segment_creator or open_template_editor. The description states only what the tool does, leaving the agent to infer its use case from the page name; no explicit exclusions, prerequisites, or alternative routing are mentioned.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.