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

Annotations already cover read-only, idempotent, non-destructive, open-world. Beyond that the description adds venue provenance (CFTC-regulated US venue vs offshore), the browse-mode behavior, and the crucial price semantics (YES-side implied probability in [0,1]). It does not mention rate limits, pagination, or result caps beyond the limit param.

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 and front-loaded: the venue distinction leads, then the query-vs-browse mechanic, then routing to sibling tools. Every sentence is functional, though the run-on construction packs several ideas into single sentences.

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 carries the return burden and does so: matching events each with child markets and live prices, plus the price interpretation rule. An agent has everything needed to call it correctly and interpret results.

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 four params, including that `category` is ignored when `query` is set. The description restates the query/browse/category interaction but adds little syntax or format detail beyond the schema. Baseline 3 is appropriate when the schema carries the load.

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 (search/discovery) and resource (Polymarket US markets) and explicitly distinguishes itself from the offshore `polymarket` pack and `kalshi`. An agent can select this over sibling venue tools without opening a schema.

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 explicit mode selection (pass `query` to search, omit to browse), names the category filter's applicability, and names the downstream tools (polymarket_us_bbo / book / price_history / settlement) that depend on the slug this returns. Nothing is left to inference.

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