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

Annotations already declare read-only, idempotent, non-destructive, and open-world. The description adds genuinely new behavioral context beyond them: public administrative data, cached and bounded results, and explicit non-behaviors (no IP geolocation, no precise address, no game mutation, no LLM call).

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?

Front-loaded with the core action in the first sentence, followed by supporting data/boundary notes. Tight and free of filler, though the trailing negative list is slightly dense.

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?

An output schema exists so return values need not be described, and annotations carry the safety profile. The description supplies data provenance, caching/bounding, and privacy boundaries, leaving only minor gaps like result limits or pagination behavior.

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% for the single 'query' parameter, so the description must compensate. It does explain that query accepts a name or a postcode, which is real added meaning, but gives no format details, casing, or matching behavior for either input style.

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 (Find), resource (French metropolitan communes), and the lookup keys (name or postcode), framed for opt-in farm weather. It is clearly distinguishable from a lookup tool, though it never names the sibling farm_weather_get it presumably precedes.

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 phrase 'for opt-in farm weather' implies this is the search step preceding farm_weather_get, but there is no explicit when-to-use, no exclusions, and no mention of the actual sibling tool. Usage is only inferable.

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