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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds meaningful behavioral context beyond that by specifying the return shape: a top-level array of event objects with key fields and a nested markets array. This helps the agent understand what the call produces without relying only on the output schema.

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 well-structured and front-loaded: purpose first, then usage guidance, then return shape, then sibling routing. Every sentence earns its place, and the alternative tool guidance is placed at the end without clutter.

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 the rich input schema, annotations, and output schema, the description covers the essential conceptual context: what an event is, how it differs from a market, how to browse/filter, what the response contains, and when to use a sibling tool. Nothing critical is missing for an agent to select and invoke this tool correctly.

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%, so the baseline is 3. The description mentions some filters (tag_slug, active, featured, archived, closed, liquidity/volume ranges) and the return fields, but it does not add substantive meaning beyond what the input schema already documents for each parameter. It is useful but not additive enough to raise the score.

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: 'List Polymarket events'. It then defines what an event is (topic-level grouping bundling related markets) and gives concrete examples (election, season-long series), making the tool's purpose unambiguous and distinct from sibling tools.

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 explicitly states when to use this tool: 'Use this to browse by subject rather than by individual question, or to find every market attached to one storyline.' It also names the alternative: 'When you already know which question you want and need its price, use get_polymarket_markets instead.' This is direct and actionable.

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