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

Annotations already declare readOnly, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds genuinely useful non-annotation context: a per-call price ($0.002/call) and the fact that each row links to a primary-source evidence pack. It still says nothing about pagination, rate limits, or freshness of 'right now', so it is only modestly above the annotation bar.

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 purpose and output fields, and reasonably tight overall. The usage sentence is partly redundant, restating 'most active prediction markets' after already saying it in the first sentence, which is minor waste rather than bloat.

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 compensates by enumerating the returned fields (question, YES odds, 24h change, volume, liquidity, end date, link), and it covers cost and tool routing. The main residual gap is the undocumented limit parameter and unstated result-count/default behavior.

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 33%: tag is documented in the schema, sort relies on an enum, and limit is undocumented beyond bounds/defaults. The description names the three sort options and gives tag examples (crypto/fed/politics), partially compensating, but it never explains what limit does, its 1-50 ceiling, or what 'tag slug' means beyond the examples.

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 resource ('the most active Polymarket markets right now') with the ranking basis (24h volume, liquidity, or 24h change) and enumerates the returned fields. It explicitly names the sibling tools it is not (polymarket_context, polymarket_edge), so an agent can distinguish it without opening any 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 routing: use this to find where prediction-market money is moving, use polymarket_context for a single market's evidence, and polymarket_edge for oracle disagreement. The when-to-use and the alternatives are both stated outright.

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