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

No annotations are provided, so the description carries the full burden. It explicitly discloses that the tool is deterministic, runs no LLM and no buyer code, returns history rather than prediction, and costs $0.25 paid via x402/USDC. This goes well beyond a bare 'runs a backtest' statement, though it omits details like authentication or rate limits.

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?

The description is long but dense: the opening sentence states the core action and rule options, the second gives selection instructions and expected outputs, and the remaining sentences add determinism, informational caveat, and pricing. Every clause contributes; there is no filler or repetition of the schema.

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?

Given no output schema and no annotations, the description compensates by listing the outputs (hit rate, return stats, drawdown, Brier score, calibration table, results by year, sample markets, exact method) and key behavioral caveats. It could still mention defaults for the optional parameters and any error conditions, but the essential context for invoking the tool is present.

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 schema already documents all seven parameters. The description adds value by defining each rule strategy (e.g., favorite_hold 'buy the side at or above p on its first such day'), which clarifies how threshold, days_before_end, and rule interact. It also clarifies category as an event tag and frames from/to as a date range.

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 precise action ('Replay') on a specific resource ('resolved Polymarket markets from a derived store of on-chain daily closes') and enumerates the four rule variants. This makes the tool's function unmistakable and sets it apart from the sibling tools, which are check/scrape/report utilities.

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 clear operating context: pick a category and date range, and notes the tool is informational, deterministic, and historical. It does not explicitly name alternatives or exclusions among siblings, but the context is sufficient for an agent to recognize when a historical backtest is appropriate.

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