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

Annotations only say read-only/open-world, but the description adds the subscription gate, the underlying GET path, pagination defaults (0/20), the response envelope {results, moreDataAvailable}, and the fact that catalogue foods carry source: FATSECRET with multiple servings. That is substantive behavior beyond the annotations.

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?

The subscription requirement is stated twice in the first two sentences ("Requires a Garmin Connect+ subscription... Needs Garmin Connect+."), which is pure redundancy, and the purpose sentence is buried behind the prerequisite rather than front-loaded. The endpoint/response detail is dense but 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?

With no output schema, the description correctly supplies the return shape and the moreDataAvailable pagination flag, plus the auth prerequisite. The main gap is that the three parameters remain semantically thin (no query format or limit bounds) for a 0%-coverage schema.

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 0%, so the description must compensate, and it does partially: it maps the parameters onto searchExpression/start/limit and supplies default values (0 and 20). It still doesn't define the query string format or any cap on limit, so it doesn't fully close the 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 clear verb+resource ("Food catalogue search") and pins the scope to the FATSECRET-sourced catalogue, which implicitly separates it from the sibling get_custom_foods. It never names a sibling directly, so differentiation requires the agent to infer catalogue-vs-custom.

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 a concrete prerequisite (Garmin Connect+ subscription) and a specific tool to verify it with (has_connect_plus), which is actionable context an agent can act on before calling. It does not, however, say when to prefer this over get_custom_foods, quick_add_food, or log_food.

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