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

Annotations already signal readOnlyHint=false and destructiveHint=false, indicating a non-read-only, non-destructive write operation. The description adds the constraint that the account must already exist, which is useful behavioral context. It does not elaborate on idempotency or side effects, but annotations cover the safety profile adequately.

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 nine words, concise and front-loaded with the action. It contains no redundancy or extraneous information, earning full marks for conciseness.

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 a straightforward create operation with six parameters, an output schema, and good annotation coverage. The description is sufficient for an agent to understand the core operation, though it does not mention the special 'isPrimary' parameter or clarify how primary contacts are handled. Given the simplicity, the description is adequately complete without needing extensive 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 covers all six parameters with descriptions at 100% coverage. The description adds no additional parameter-level detail, so it does not improve upon the schema. Baseline 3 is appropriate given the schema already provides full semantics.

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 'Create' with the resource 'contact' and specifies the context 'on an existing CRM account,' clearly distinguishing this from sibling tools like create_account or create_deal. It implies a prerequisite (existing account) and is unambiguous.

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 states the tool creates a contact on an existing account, implying the need for an existing accountId. However, it does not provide explicit guidance on when to choose this over alternatives like create_lead or update_contact, nor does it mention any exclusions or prerequisites beyond 'existing CRM account.'

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