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. It states what the tool does but doesn't describe how it behaves: no information on permissions needed, rate limits, error conditions (e.g., invalid addresses), output format (e.g., raw code, metadata), or whether it's a read-only operation. This leaves significant gaps for safe and effective use.

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 with no wasted words. It is front-loaded with the core purpose ('Get the source code'), making it easy to scan and understand quickly. Every part of the sentence contributes directly to explaining the tool's function.

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 complexity of retrieving smart contract code (which may involve blockchain interactions, authentication, or formatting), the description is insufficient. With no annotations and no output schema, it doesn't cover behavioral aspects like error handling, response structure, or limitations. The description alone doesn't provide enough context for reliable agent use.

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, with the 'address' parameter fully documented in the schema (including format and pattern). The description adds no additional parameter semantics beyond implying the address is for a smart contract, which is already clear from the tool name. This meets the baseline for high schema coverage.

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 ('Get') and resource ('source code for a smart contract'), making the purpose immediately understandable. It distinguishes from siblings like 'get-contract-abi' (which retrieves ABI) and 'get-transactions' (which retrieves transaction data). However, it doesn't specify the verb tense or scope details like whether it retrieves all source code or specific versions.

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. It doesn't mention prerequisites (e.g., needing a contract address), exclusions (e.g., not for non-contract addresses), or comparisons with siblings like 'get-contract-abi' for interface data. The agent must infer usage from the name and schema alone.

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