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

Annotations only declare readOnlyHint=true, so the description carries the rest: mm_* and open_interest are contract counts not dollars, mm_* covers one category per family (Managed Money vs Leveraged Funds), an unreachable store is REFUSED (DATA_UNAVAILABLE), plus source/attribution and computed-field disclosure (mm_net). This is unusually rich behavioral context.

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?

Dense but front-loaded: the core purpose and the market/omit branch come first, with caveats, limits, and attribution following. Every sentence carries load, though the all-caps emphasis and stacked details make it slightly heavier than needed.

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 still names the response keys, explains field units and which speculative category applies, discloses truncation caps and the failure mode, and points to tool_notes for caveats. An agent has everything required to call and interpret it.

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 100% so the baseline is 3, but the description adds value beyond it: name normalization examples ('wti', 'GOLD', 'e-mini s&p' resolve), the series-only scope of `limit`, and its default/cap in prose. Minor gaps remain (no note on what an unmatched market returns), keeping it from a 5.

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+resource: CFTC Commitments-of-Traders positioning for three named curated markets, with return shape {summary, market, matched_market, rows}. No sibling tool covers COT positioning, and the description makes the scope unambiguous.

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 says to pass `market` for a weekly history or omit it for the latest all-market snapshot, and notes the series-only restriction on `limit`. Clear within-tool usage guidance, though it doesn't route to alternative sibling tools (none exist for this data).

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