evm_sign_message

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

Annotations already provide openWorldHint and destructiveHint, so the safety profile is known. The description adds the 'active wallet' scoping, which is useful context, but it does not disclose other behavioral traits such as whether a signature is returned, whether any transaction is broadcast, or if any side effects occur beyond signing. No contradiction with 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 a single, concise sentence that gets straight to the point. Every word earns its place, and the key qualifier 'arbitrary UTF-8' is placed immediately to clarify the message scope.

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 simple tool with one parameter and no output schema, the description is largely sufficient. It covers the signing intent and active-wallet context. It could mention the output (a signature) or call out that no transaction is broadcast, but given the tool's simplicity and the annotations, the slight omission is not a major gap.

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% for the single 'message' parameter, providing the baseline. The description's phrase 'arbitrary UTF-8 message' adds meaningful semantics about accepted formats (any string encoded as UTF-8) that go beyond the schema's terse 'Message to sign'.

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 action ('Sign'), the resource ('arbitrary UTF-8 message'), and the context ('with the active wallet'). This distinguishes it from sibling tools like evm_sign_typed_data (which signs typed structured data) and sign_message (generic, not EVM-specific).

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 gives no explicit guidance on when to use this tool versus alternatives. It does not mention that evm_sign_typed_data should be used for typed data, nor does it clarify any prerequisites like wallet activation. The usage context is only implied by the tool name and the phrase 'active wallet'.

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