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

Annotations already declare readOnly, idempotent, and non-destructive behavior, and the description adds substantial value beyond that: ascending order, ISO 8601 timestamps, decimal-string USDC prices, 24-hour default window, 31-day cap, downsampling behavior, and empty-result semantics. There is no contradiction with the 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, information-carrying sentences with the core purpose front-loaded. Every sentence adds meaningful behavior or edge-case context; there is no filler or redundancy.

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 read-only historical-data tool with an output schema and rich annotations, the description covers output format, time-window behavior, downsampling, and empty results. The main gaps are that startTime/endTime input formats are left to inference and the platform parameter supports kalshi while the description only refers to the Polymarket API.

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 only 20%, so the description must compensate. It does clarify window defaults/cap and that fidelityMinutes controls sample spacing, but it never explicitly defines startTime/endTime input formats or tokenId requirements, leaving important parameter semantics incomplete.

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: 'Fetches price history for one outcome token from the Polymarket Data API.' It further distinguishes itself from sibling market-data tools by clarifying that points are upstream price samples derived from trade activity, so an agent can tell this from get_market_trades or get_market_quotes without inspecting schemas.

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 usefully explains defaults, the 31-day cap, and fidelity spacing, but it never explicitly states when to choose this tool over alternatives or when not to use it. Selection guidance is implied rather than stated.

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