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

Annotations already declare read-only, idempotent, open-world, non-destructive, so the description is free to add the traits that actually matter: the call is paid ($0.01 USDC via x402 on eip155:8453), results come from two catalogs merged and de-duplicated, and each result carries URL, description, method, network and USD price. That is substantive context beyond the structured fields.

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?

Three tight sentences that front-load the purpose, then the sourcing/merge behavior, then filters and price. Slight redundancy in that the opening sentence restates the title verbatim, but no sentence is wasteful.

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 read-only search with no output schema, the description covers the return shape (URL plus description, method, network, price), the sourcing, the filters and the cost. It leaves out result-count/limit behavior and what happens if payment is absent or a catalog is unreachable, which an agent would benefit from knowing.

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 only 25% (only network is documented inline), so the description must compensate, and it does for three of four parameters: keyword query, network filtering, and maximum price in USD. The limit parameter (1-50, default 20) is never mentioned, leaving one meaningful gap.

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) plus the exact resource (public discovery catalogs of the Coinbase CDP and PayAI facilitators), and describes the merge/deduplicate scope. The added 'with prices' and 'paid APIs' qualifiers separate it cleanly from sibling tools like x402_check, which is not described as a catalog search.

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 clear context for when to reach for it (keyword search across public discovery catalogs, optional network or max-price narrowing) and warns that each call costs $0.01 USDC, which shapes invocation decisions. It never states when not to use it or points to x402_check as the single-resource alternative, so explicit exclusions are missing.

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