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

With no annotations, the description carries the full disclosure burden, and it does surface two non-obvious traits: a per-call price ($0.02 via x402) and an alternate subscription path, plus that prices and volumes come back normalised. It still omits rate limits, pagination behaviour, failure modes, and how the two auth paths interact, so the behavioral picture is incomplete.

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?

Two sentences, zero padding, and the cost note is placed first so an agent sees the paid precondition before deciding to call. Slightly at odds with front-loading the core purpose, but defensible for a metered tool.

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 four-parameter search tool with no output schema and no annotations, the description covers purpose, cost, source venues, and the shape of returned data. It leaves gaps around result ordering, pagination past the limit, and error/empty-result behaviour that an agent would want before relying on 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 75%, so limit and venue are already documented, and access_token explains its own source. The description's example keywords ('fed rate', 'bitcoin', 'election') add real meaning about what query accepts — free-text topic terms rather than market IDs or slugs — which the bare string schema does not convey.

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 gives a specific verb and resource ('Keyword search across live Polymarket and Kalshi markets') plus concrete example queries, so an agent knows exactly what the tool returns conceptually. It does not name or distinguish itself from close siblings such as market_lookup or live_markets, which keeps it short of a 5.

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?

Usage is implied by 'keyword search' plus example keywords, and the payment line signals a cost prerequisite an agent should consider before calling. There is no explicit guidance on when to prefer market_lookup or live_markets instead, and no stated exclusions.

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