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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safe read-only nature is clear. The description adds context about being public data only and paid per call, but it does not detail what happens with the data (e.g., no caching, rate limits). Since annotations cover safety, the description's contribution is moderate, and a 3 is appropriate.

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?

The description is concise and front-loaded with the core purpose, then lists optional filters, and ends with critical notes (public data, paid). It uses 3 sentences with no fluff, and each sentence adds value. It's efficient for an agent to parse.

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 the tool's complexity (4 optional params, no output schema), the description covers the usage context well: it explains what data it returns (prices, cheapest matches, distribution), the public nature, and payment. It lacks explicit mention of error behaviors or rate limits, but for a simple list-filter tool, it's nearly 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 description coverage is 100%, meaning each parameter (type, limit, query, max_price_usd) already has a description in the schema. The tool description does not add meaningful detail beyond restating the filters (keyword, resource type, max price) that are already in the schema. It's baseline 3 with high coverage.

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 clearly states the tool's purpose as x402 market intelligence, listing the specific directories (Bazaar and x402scan) and the resource type (prices of other agents/services). It distinguishes itself from siblings like paid_crypto_price and paid_model_price by focusing on market prices of agents/services in x402 directories, which is specific and not redundant.

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 provides clear context on when to use it—for market intelligence on other agents/services in public directories—but does not explicitly state when not to use it or name alternatives. However, the sibling names (e.g., paid_crypto_price, paid_model_price) are distinct enough that an agent can infer the difference, but the description could have explicitly said 'Use this for market prices, not for your own pricing'.

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