sign_message

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

With no annotations, the description carries full responsibility for disclosing behavior. It only states the signing operation and does not mention the output format (e.g., signature string), any side effects, or how the private key is handled—though the schema's privateKey description covers some security aspects, the tool description itself adds no behavioral context.

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, succinct sentence that gets straight to the point. It includes the essential method (personal_sign/EIP-191) without any wasted words.

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?

The tool is simple and the schema fully documents its two parameters, but there is no output schema and no annotations. The description does not explain the return value (the signature) or provide usage context, leaving some gaps for an agent unfamiliar with EIP-191 personal_sign.

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 parameters (message and privateKey) described in the schema. The description adds no extra parameter-level detail beyond naming the scheme, 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 action ('Sign') and the resource ('a message'), and specifies the exact signing scheme ('personal_sign (EIP-191)'). This distinguishes it from related tools like sign_typed_data and hash_message, making its purpose 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?

No guidance is provided on when to use personal_sign versus alternatives such as sign_typed_data or hash_message. The description does not mention any exclusions or scenarios, leaving the agent without situational context.

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