EVM MCP Server

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

The description adds valuable context beyond annotations: it specifies the signature follows EIP-712 standard, mentions use cases, and clarifies the wallet is 'configured' (implying setup requirements). Annotations cover idempotency (true) and non-destructive nature (false), but the description provides practical application context that helps the agent understand when this tool is appropriate.

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 perfectly concise with just two sentences. The first sentence states the core purpose, and the second sentence provides essential context about the standard and use cases. Every word earns its place with zero redundancy.

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 cryptographic signing tool with good annotations and full schema coverage, the description provides excellent context about use cases and the EIP-712 standard. The main gap is lack of output information (no output schema), but the description compensates well by explaining what the tool produces ('signature follows the EIP-712 standard').

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?

With 100% schema description coverage, the input schema already fully documents all 4 parameters. The description doesn't add any parameter-specific information beyond what's in the schema descriptions, so it meets the baseline expectation without providing additional parameter semantics.

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 specific action ('Sign structured data'), the standard used ('EIP-712'), and the resource ('using the configured wallet'). It distinguishes this tool from sibling tools like 'sign_message' by specifying it's for structured data following a particular standard rather than plain messages.

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 explicitly lists multiple use cases ('gasless transactions, meta-transactions, permit signatures, and protocol-specific signatures'), providing clear guidance on when to use this tool. It differentiates from 'sign_message' by specifying EIP-712 structured data signing rather than general message signing.

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