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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds real value beyond them by disclosing the derivation ('venue's first-in-first-out paired closes') and the nature of the metric (realized, backward-looking), which is exactly the context needed to avoid misreading it as predictive.

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?

Two tight sentences with the output contents front-loaded and no filler. The second sentence is an interpretive guardrail rather than a description of the tool itself, which is slightly off-topic for a definition but conceptually adjacent and worth its length.

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 only one parameter, full schema coverage, no output schema, and annotations carrying the safety profile, the description fills the remaining gaps by enumerating the returned fields and setting expectations about what the record is not. Nothing needed to call it correctly 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?

Schema description coverage is 100% and the single 'model' parameter is documented in the schema as the attribution from the models tool (starting with 'llm-'). The description adds nothing about the parameter, so the baseline of 3 for high schema coverage applies.

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 names a specific resource (one trading model's record) and enumerates exactly what it contains: realized PnL, max drawdown, win rate, per market, and the window. It also explicitly differentiates from siblings by stating it is neither a forecast nor a follower's simulated return, which is the distinction an agent needs against forecast/follow_quote.

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?

It gives clear context via exclusion: 'Always say what the record is not: a forecast, or what a follower would have made,' which implicitly routes the agent to the forecast and follower tools for those questions. It stops short of naming the alternative tools or stating a positive when-to-use trigger, so it is clear but not fully explicit.

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