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

Beyond the annotations it discloses pricing ($0.01/call, free tier of 10 requests, free failures), which usefully explains the non-idempotent hint, and restates that the call is read-only. That is meaningful cost and side-effect information an agent needs for planning; it does not cover result pagination or rate-limiting beyond the flat price.

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?

It front-loads the action and return payload, then moves to use cases and pricing, with almost no wasted wording. The parenthetical keyword list and the multi-clause first sentence make it denser than necessary, but nothing is truly redundant.

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 3-parameter search tool with no output schema, the description covers what comes back, how to use it, what it costs, and that it is non-mutating — everything needed to invoke it correctly and budget for it.

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 parameters are already fully documented in the schema, including the 1-20 limit range and the closed flag. The description only adds an example query value and the implication that results default to open markets, which is marginal added meaning.

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 states a specific verb and resource — 'Search Polymarket prediction markets by keyword' — and enumerates the returned fields (odds as implied probabilities, bid/ask, volume, liquidity, end date, token ids). The line 'find a market before reading its order book' implicitly separates it from polymarket_orderbook, and the keyword framing distinguishes it from plain listing siblings.

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 names three concrete use cases (look up odds on an event, locate a market before reading the order book, feed a forecasting agent) and gives a worked example (q=bitcoin). It stops short of naming a named alternative for when keyword search is the wrong choice (e.g., browse-all vs search), so no explicit exclusion.

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