EVM MCP Server

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

Annotations already provide readOnlyHint=true, destructiveHint=false, openWorldHint=true, and idempotentHint=true, covering safety and idempotency. The description adds no behavioral context beyond what annotations declare (e.g., no rate limits, error conditions, or performance traits). With annotations doing the heavy lifting, the description meets the baseline but adds minimal extra value.

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, efficient sentence that front-loads the core purpose ('Lookup the ENS name for an Ethereum address') and adds clarifying context ('reverse resolution') without redundancy. Every word earns its place, making it optimally concise and well-structured.

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?

Given the tool's low complexity (simple lookup), rich annotations (covering safety and idempotency), and high schema coverage, the description is mostly complete. However, the lack of an output schema means the description could benefit from hinting at return values (e.g., ENS name or null). It's adequate but has a minor gap in output context.

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%, with both parameters ('address' and 'network') fully documented in the schema. The description does not add any parameter-specific details beyond what the schema provides (e.g., no format examples for 'address' or default values beyond schema's note). Baseline score of 3 is appropriate when schema coverage is high.

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 ('Lookup the ENS name') and resource ('for an Ethereum address'), with the parenthetical 'reverse resolution' distinguishing it from the sibling 'resolve_ens_name' tool (which presumably does forward resolution from name to address). This precise verb+resource pairing and explicit sibling differentiation earns the highest score.

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 context through 'reverse resolution,' which helps differentiate from 'resolve_ens_name.' However, it lacks explicit guidance on when to use this tool versus alternatives (e.g., when you have an address vs. a name) or any prerequisites. The context is clear but not comprehensive enough for a perfect score.

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