Create forwarder

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

Annotations already indicate this is a mutating operation (readOnly=false). The description adds a non-obvious consequence: the destination must confirm before forwarding activates, so the agent knows not to expect immediate effect. It also explains the side-effect email to the destination address, going beyond 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?

Two sentences, no redundant or promotional language. The core action and the critical side effect are both 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 three-parameter creation tool, the description covers the action, the two required inputs, and the confirmation delay that affects expected outcomes. It does not describe the response format or how to resend the confirmation email, but those are less critical for correct invocation given the rich schema and sibling 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?

Schema already documents mailboxId, destination, and is_keep_copy_enabled with full coverage, so the description only needs to reinforce the key inputs. It maps 'given mailbox' to mailboxId and 'destination address' to destination, but does not add meaning for is_keep_copy_enabled; that is acceptable because the schema covers it.

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 verb ('Create'), a specific resource ('forwarder'), and the source-destination relationship, so it is immediately clear what the operation does. The added confirmation detail differentiates this creation flow from list/update/delete forwarder 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 establishes when the tool is applicable (setting up forwarding from a mailbox), but it does not explicitly state when to prefer it over mail_createAliasV1 or mail_updateForwarderKeepCopySettingV1, nor does it mention that resending confirmation is handled by a sibling. The 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.