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

Annotations already cover safety (readOnly, idempotent, closed-world), so the description's added value is the query-mode behavior and the id-handoff return contract, both useful beyond structured fields. It says nothing about result ranking, whether the whole corpus is indexed, or how `limit` affects results, which keeps it from a 5.

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 tight sentences: what it searches, how to query it, what you get back. The corpus scope is front-loaded and every clause carries information an agent would otherwise have to guess.

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 an output schema present, the description only needs to say what comes back, which it does ('ids to pass to `fetch`'). Combined with the query-phrasing guidance, an agent has enough to call it correctly; the silent `limit` parameter and unspecified ranking/pagination behavior are the remaining 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 67% — `query` and `scope` are documented inline, while `limit` has no description anywhere. The description reinforces query syntax with concrete token examples, which is genuine added meaning, but it never mentions `scope` or the result-count cap, so it doesn't compensate for the coverage gap.

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 ('Full-text search') and names the exact resource scope: guide sections, changelog, pricing, endpoints and response models. The closing sentence ('Returns ids to pass to `fetch`') separates it from the fetch sibling, and the resource framing distinguishes it from list_endpoints/get_endpoint without opening any schema.

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?

Gives concrete guidance on how to phrase queries ('exact tokens work best... plain questions work too') and the follow-up step ('ids to pass to `fetch`'). It stops short of explicitly saying when to prefer get_endpoint or list_endpoints for a known endpoint name, so the routing against the other two siblings is left implicit.

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