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

Annotations already declare this is a read-only, idempotent, non-destructive lookup, so safety is covered. The description adds real behavioral context beyond the annotations: a hard cap of 25 results per call and the absence of pagination, with the workaround ('narrow the area'). It stops short of describing result ordering or what fields come back, hence not 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?

Four sentences, all load-bearing: search modes, input constraint, return-cap behavior, and the handoff to get_gym. The input constraint appears early, before the return semantics, which is the right front-loading for a search tool.

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?

There is no output schema, so the description must carry return semantics, and it does: result count cap, no pagination, and that each gym carries a link to a public page holding contacts and full details. Combined with annotations and a fully documented schema, an agent has everything needed to call and interpret this tool.

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%, so the baseline is 3. The description adds meaning the schema does not: that city/country/lat+lng are alternative rather than required inputs, and the practical workaround for the result cap. It doesn't restate the enum, radius, or default values, which is appropriate since the schema handles them.

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 ('Find Brazilian jiu-jitsu and grappling gyms') plus the three supported search modes. It also distinguishes itself from the sibling get_gym by name, so an agent can route correctly without opening either 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?

Explicitly states the precondition ('Give at least one of: city, country, or lat+lng') and names the alternative tool for a different need ('Use get_gym with the slug for the class schedule and what the gym offers'). When-to-use and when-to-use-something-else are both covered.

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