Get one Polymarket market

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds value beyond that with an explicit error string ('No market found for slug …') and the returned field set, though it does not discuss rate limits or pagination (none apparently needed for a single-item fetch).

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?

Front-loaded with the core action, then Args, Returns and Errors in a scannable structure. The verbose Returns enumeration partially duplicates the existing output schema, which is the one place words are spent that structured data already covers.

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 simple two-parameter read tool with an output schema present, the description supplies everything needed: required arg source, format option, error condition and recovery path. Nothing an agent needs 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 coverage is 100%, so the baseline is 3, and the description goes slightly beyond by explaining the provenance of slug (from polymarket_search_markets) and the markdown-vs-json tradeoff. The added meaning is marginal but real, particularly the link between slug lookup and downstream token ids.

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 and resource ('Fetch the full detail of a single market by its slug') and names the distinguishing payload ('CLOB token ids for each outcome'), which separates it cleanly from polymarket_search_markets. An agent can tell what it retrieves without opening the 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 two explicit triggering conditions: following a market you already know, or following a search to obtain the exact token ids that the order book / price history tools require. It also routes the agent to polymarket_search_markets for slug recovery, so the when-to-use and alternative are both covered.

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