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

The description discloses that the tool returns the recovered address rather than a bare boolean, enabling independent comparison, and explains why that design exists. It also reveals expiration semantics: a genuine signature past expiresAt means the score was valid when issued and should be refetched, not that it was forged. Annotations already mark readOnly and idempotent; the description adds meaningful behavioral context without contradicting them.

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 longer than typical, but every sentence earns its place: core purpose, return value, why to avoid the tool, offline alternatives, and expiration caveat. It is front-loaded with the primary check and scoping, and the warning is presented as 'IMPORTANT, AND THE WHOLE POINT,' making the structure easy to follow. There is no filler or repetition.

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 no output schema, the description covers the return values, the rationale for the return shape, and the expiration edge case, giving an agent enough to decide whether and how to call it. It omits explicit error behavior for malformed signatures or mismatched addresses, but the strong 'do not use this tool' guidance reduces the impact of that gap. Overall it is highly complete for its complexity.

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%, with both message and signature already described precisely ('newlines and all', '0x-prefixed'). The description restates the parameters but adds no new format or syntax details beyond the schema. Baseline 3 is appropriate because the schema carries the parameter documentation burden.

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 specific verb and resource: 'Check whether a Patina attestation really was signed by Patina.' It clearly scopes the tool to signature verification and distinguishes it from siblings like check_threshold or get_patina_score by stating the return tuple: recovered address, published address, and match. This is unambiguous and immediately tellable apart from other tools.

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?

Explicitly instructs when not to use the tool: 'you do not need this tool, and where you can, you should not use it,' and names offline alternatives (viem's recoverMessageAddress, ethers' verifyMessage). It explains the reasoning—server-side verification reintroduces trust in Patina—giving a clear condition for avoidance. This is strong usage guidance beyond any sibling description.

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