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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds one genuinely useful behavioral detail, that it emits a ready-to-use run_check call, but says nothing about caching, cost, or failure modes.

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?

A single compact sentence with no filler, front-loading the returned facets. Slightly cryptic domain terms ('market', 'coverage') keep it from being fully self-explanatory, but nothing is wasted.

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 carries the return-value burden by naming the facets returned. For a one-parameter read tool this is nearly sufficient; only the vague terms 'market' and 'coverage' and the unelaborated run_check payload leave small 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 description coverage is 100% with a single required check_id, so the schema carries the parameter burden. The description only reinforces the 'one check' scope and adds no syntax, format, or sourcing detail beyond what the schema already states.

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 resource (one check) and enumerates the payload facets it returns (inputs, output, market, coverage) plus a runnable run_check call. This distinguishes it from search_checks and run_check without opening a schema, though the telegraphic noun-phrase style omits an explicit verb.

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?

Usage is only implied: the phrase 'plus a ready run_check call' hints at a describe-then-run workflow, and the schema notes check_id comes 'From search_checks'. There is no explicit when-to-use/when-not or direct comparison against the search_checks sibling.

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