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

Annotations only declare readOnlyHint and openWorldHint, but the description adds substantial context: it's a best-match-first search over a specific third-party catalog, scoped to the networks pay_x402 actually pays on, and it surfaces each seller's payout record. This goes well beyond the annotation signals.

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-loads what it searches and what the results contain, then gives usage and evaluation guidance. It is dense and slightly run-on, but every sentence carries actionable information rather than filler.

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 does enough by outlining what comes back (sellers with payout records, ordered by match and constrained by price). Minor gap: it doesn't describe the shape of a result or how many fields each seller entry has, but for a read-only open-world search this is sufficiently complete.

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, but the description adds meaning: query should be the natural-language gist in any language, and the price filter is bounded by the USDC-on-Base/Solana networks pay_x402 uses. It also states results are ordered best match first, which informs how limit behaves.

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 (Search) and resource (public x402 catalog / Coinbase x402 Bazaar) for paid APIs settling in USDC on Base or Solana. Clearly distinct from siblings like pay_x402 (payment) and check_text, so an agent can route without opening schemas.

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?

Explicitly says when to use it: 'whenever the owner asks for something you can't answer yourself (live weather, prices, news, safety checks...)', in any language, passing the gist as the query. Also adds evaluation guidance (listings are not recommendations; prefer clear descriptions, long payout records, fair prices).

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