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

With no annotations, the description carries the burden, and it does well: it discloses the data source (Circle's x402 catalogue), freshness (refreshed daily), ordering (cheapest first), and that it includes 'our own products with their prices for comparison.' It also states it is free. It does not mention pagination or rate limits, but the schema's limit parameter covers pagination.

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 sentences, front-loaded with the core question, then the resource, ordering, fields, and use case. Every sentence earns its place; the final 'Free.' is a useful behavioral note, not 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?

For a search tool with 4 optional params and no output schema, the description is nearly complete: it names the catalogue, the ordering, the fields returned, and the use case. It does not describe the output shape, but with no output schema and a simple search result, the description's field list (host, path, category, settlement) gives the agent enough to know what to expect.

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. The description adds context for query ('keywords') and maxPrice ('optional price cap in USD') but does not add meaning beyond the schema for limit or network. The description's mention of 'cheapest first' and 'by keyword' reinforces query semantics but does not substantially exceed the schema.

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 opens with a concrete question ('Who sells this on Arc, and for how much?') and states the resource (Circle's x402 catalogue), the action (search by keyword, cheapest first), and the returned fields (host, path, category, settlement). It also distinguishes itself from the broader catalog_browse/catalog_product siblings by specifying it searches Circle's own x402 catalogue.

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 explicitly tells the agent when to use it: 'Use it to price a service before you build or buy it.' It also frames the catalogue as what Circle CLI agents buy from, refreshed daily, which implies it is the authoritative pricing source. It does not name alternatives, but the use case is so specific that an agent can route correctly.

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