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

Beyond the readOnly/openWorld annotations it discloses three non-obvious traits: the data is wins-only (a semantic limitation that changes interpretation), `available:false` signals the archive is unpublished, and no API key is required. These are exactly the facts an agent cannot infer from annotations or an empty schema.

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?

Three tight sentences, front-loaded with the returned aggregate, then usage, then error/auth notes. Every clause carries information; nothing is redundant.

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With no output schema, the description enumerates the returned figures and the sentinel value for the unpublished case, so an agent knows both what it gets back and how to interpret failure. Nothing needed to call or interpret this tool is missing.

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?

The tool takes zero parameters, so the baseline is 4 and there is nothing further for the description to disambiguate. No parameter guidance is needed or missing.

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 (the settled-wins archive) and enumerates exactly what the aggregate contains: markets won, net and winners' realized profit, first/last settlement, per-category breakdown, top traders. This clearly separates it from the listing/search siblings get_settled_win, search_settled_wins, and list_categories.

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 an explicit use context ('how has this roster done overall') plus a mandatory caveat (wins-only) that conditions how the result should be interpreted. It stops short of naming an alternative tool for the non-aggregate case, so it is clear but not fully routing.

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