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

With no annotations provided, the description carries the full burden. It discloses the paid nature ($0.01 USDC per call), the synchronous JSON response, the 404-on-miss behavior with auto-cancel of payment, and the output license (CC0). This is strong behavioral disclosure for a paid API, though it doesn't detail rate limits or error formats beyond 404.

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 dense but well-organized: it front-loads the core purpose, then pricing, then behavior, then output license. Every sentence adds information. It's slightly long but justified given the paid nature and the need to explain the 404 auto-cancel behavior.

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 single-parameter lookup tool with no output schema, the description covers the essential context: what it does, what it costs, what it returns, and what happens on a miss. It doesn't explain the x402 payment flow in detail, but that's likely an external protocol detail. The main gap is not describing the response structure, but the description lists the fields returned, which partially compensates.

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% and the single parameter 'query' is already described in the schema with examples. The description adds context that the query is free-text and resolves to one entry, but it doesn't add meaning beyond what the schema already provides. Baseline 3 is appropriate.

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 ('read API'), a specific resource ('cc0pedia'), and a precise scope ('ONE entry resolved from a free-text query'). It also names the data fields returned (provenance, creator, license, on-chain pointers, CC0 body), which distinguishes it from sibling tools like cc0pedia-search or cc0pedia-verify.

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 clearly says this is a lookup tool for a single entry from a free-text query, and the sibling list includes cc0pedia-search, implying search is the alternative for broader queries. However, it doesn't explicitly state 'use cc0pedia-search instead for multiple results' or give when-not-to-use conditions, so it stops short of a 5.

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