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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds beyond that: the result is 'bounded weekly history' with 'pagination', 'source ids', and 'provenance', and warns 'Report-family categories are enforced; not trading advice.' This gives the agent useful expectations about output size, reproducibility, and validation without contradicting 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?

Four dense sentences, each earning its place: purpose, return contents, use cases, and caveat. Front-loaded with the core action, then examples and constraints. No filler or repetition of schema details.

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 9-parameter tool with no output schema, the description plus fully-covered schema is largely sufficient. It lists return contents, examples, and a validation caveat. The only mild gap is not explicitly routing ambiguous market names to cftc_cot_search_markets, but the schema's market parameter already says 'Search first when the name is ambiguous.'

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 echoes 'report family, scope, and trader category' and hints at 'bounded' pagination, but adds no parameter-specific details beyond what the schema already documents. It is not misleading but also not compensatory.

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?

The description opens with a specific verb and resource: 'Return a bounded weekly history for one CFTC contract market, report family, scope, and trader category.' The examples ('managed money net positions in crude oil over time', 'commercial gold COT history') make the time-series nature unmistakable. Though no sibling is named, 'bounded weekly history' inherently differentiates it from cftc_cot_latest and cftc_cot_compare.

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 description provides explicit use cases: time-series positioning questions and reproducible charts. It does not state when NOT to use it or name alternatives (e.g., cftc_cot_latest for the current snapshot, cftc_cot_search_markets to resolve names), but the context is clear enough for an agent to select it for historical queries.

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