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

With no annotations provided, the description carries the full burden of behavior disclosure. It mentions catalog size and that it spans facilitators, which is useful, but it doesn't disclose search semantics (e.g., partial/fuzzy matching), result ordering, pagination behavior, or whether the agent_id parameter is required for authentication vs filtering. The 'whole catalog' claim is a behavioral trait but lacks depth.

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, both purposeful: the first states the core function and scope, the second provides ecosystem context. The information is front-loaded, and there is no filler. Slightly more detail on agent_id could be added, but as written it is tight and readable.

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 0% schema coverage, no annotations, no output schema, and four parameters including a required one, the description is far from complete. It explains the search scope but not how to form a valid request, what the response looks like, or what agent_id is for. An agent would need to guess at parameter semantics and result 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 0%, so the description must compensate for the four undocumented parameters. It explains q conceptually ('task') and max_price_usd ('price') via the phrase 'by task and price', but it leaves agent_id completely unexplained (despite being the only required parameter) and doesn't clarify limit semantics. This is a material gap for a tool whose schema offers zero descriptions.

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 ('Find') and resource ('an x402 service by task and price across the whole catalog'), and differentiates itself from siblings by noting it is a discovery layer over the entire x402 ecosystem with 27k+ listings. It doesn't explicitly name alternatives, but 'no unified search across facilitators' conveys its unique role among 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?

The description implies when to use it: when searching for a service by task and price, and it positions itself as the cross-facilitator discovery layer. However, it doesn't explicitly say when not to use it or point to alternatives (e.g., x402_service_check for verifying a specific service). No exclusions or routing conditions are given.

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