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

Annotations already declare readOnlyHint=true, so the description correctly avoids restating that. It adds meaningful behavioral details: the $0.03 USDC cost via x402 on Base, and the 3-5 sentence explanation length. It also references the POST /v1/check/explain endpoint for clarity. No contradictions with the annotations.

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 two sentences with no redundancy. It front-loads the key differentiator (explanation) and the cost, then clarifies it matches presign_check's verdict/reason codes. Every sentence earns its place, making it highly efficient.

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 tool with 11 parameters, the schema handles parameter semantics well. The description covers the purpose, cost, output content (verdict/reason codes plus explanation), language options, and references an endpoint. It doesn't detail the exact response structure, but no output schema exists, and the mention of 'verdict and reason codes' is sufficient for an agent to understand the expected outcome.

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%, so the schema already documents every parameter. The description adds only marginal value, such as indicating the lang parameter is for the explanation language, which is already in the schema. It does not provide additional syntax or format details beyond the schema, so the baseline of 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 clearly states the tool's function: a pre-sign risk check that returns the same verdict and reason codes as presign_check, but adds a plain-language explanation. This explicitly distinguishes it from its primary sibling, presign_check, by the added feature. The verb and resource are specific, and the tool's purpose is unambiguous.

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 usage when a human-readable explanation is needed by contrasting with presign_check ('same as presign_check, plus explanation'). It also mentions the cost, which is a practical consideration. However, it does not explicitly mention when not to use it or alternative tools like presign_quick_check or token_verdict, leaving some room for interpretation.

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