MCP Etherscan Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While 'Check' implies a read-only operation, it doesn't specify whether this requires network access, has rate limits, returns real-time or cached data, or what happens with invalid addresses. This leaves significant gaps for a tool interacting with blockchain data.

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, clear sentence that efficiently communicates the core functionality without any wasted words. It's perfectly front-loaded with the essential information.

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 blockchain query tool with no annotations and no output schema, the description is insufficient. It doesn't explain what the balance check returns (e.g., in wei or ETH, with decimals), whether it includes pending transactions, or any error conditions. Given the complexity of blockchain interactions, more context is needed.

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?

The input schema has 100% description coverage, clearly documenting the single 'address' parameter with format and pattern. The description adds no additional parameter information beyond what the schema provides, so it meets the baseline for high schema coverage without adding extra value.

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 ('Check') and resource ('ETH balance of an Ethereum address'), making the tool's purpose immediately understandable. However, it doesn't differentiate from sibling tools like 'get-token-transfers' or 'get-transactions' that might also involve balance-related queries, so it doesn't reach 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 provides no guidance on when to use this tool versus alternatives. With siblings like 'get-token-transfers' or 'get-transactions' that might provide related information, there's no indication of when this specific balance check is preferred or what its limitations are.

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