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

With annotations only covering safety flags, the description carries the burden and delivers: it states the tool places no call, explains billing ('billed against the same credit balance calls use; a request that returns no candidates or is refused is not'), and defines the degraded/degradation_reason and short_list_reason semantics. This is behavior an agent could not infer from the structured fields.

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?

Purpose, safety, and billing are front-loaded, and each sentence carries real information. The final sentence about the three qualifying fields is a long run-on that could be split, but nothing is 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 3-param tool with no output schema, the description does the heavy lifting on returns — naming venue name, dialable number, fit rationale, and brief, plus the three qualifier fields. It leaves the meaning of 'limit' and 'location_hint' entirely undocumented, which is the main remaining 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 0% across three parameters, and the description compensates only for 'query' by describing it as a natural-language request. Neither 'limit' nor 'location_hint' is mentioned, so the agent gets no guidance on result count or geographic scoping from either source.

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 and resource ('Return candidate US businesses to phone for a natural-language request') with a concrete example, and the clause 'Reads place data only; places no call' cleanly separates it from the sibling place_call. An agent can tell this is a discovery/retrieval step distinct from actually dialing, 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?

The example use cases ('booking a restaurant or asking a shop a question') and the note that it feeds phone calls give clear context for when to reach for it. There is no explicit when-not or a named alternative (e.g., 'use place_call to actually dial'), 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.