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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds value beyond annotations by disclosing that the response is merged with provider pipeline data and specifically what it includes (next actor, booking link, final outcome). No contradiction 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?

Two sentences with no filler. The first sentence front-loads what the tool returns, and the second provides a practical user-facing query it answers. 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 read tool with a full output schema and complete annotations, the description covers the essential context: what is returned, the enriched fields, and the intended use case. It could mention why one would prefer this over itin_list_itin_applications, but that 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%, and the sole parameter applicationId is documented as a UUID value wrapper. The description does not add extra parameter-level semantics, but with a single well-documented parameter and full schema coverage, 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 ('Returns'), a precise resource ('one ITIN application'), and the enriched content ('merged with the provider pipeline: who acts next, the identity-call booking link... final outcome'). This clearly distinguishes it from the sibling itin_list_itin_applications, which returns collections rather than a single enriched application.

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 a strong, concrete use case: "Use this to answer 'any news on my ITIN?'" This tells an agent when the tool is appropriate. It does not explicitly name alternatives or state when not to use it, but the usage context is clear enough for a single-application lookup tool.

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