EVM MCP Server

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

No annotations are provided, so the description carries full burden. It states the return type ('count of NFTs') but doesn't disclose behavioral traits like error conditions, rate limits, authentication needs, or whether it's a read-only operation (though implied by 'Get'). For a tool with zero annotation coverage, this leaves significant gaps in understanding how it behaves.

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?

Two sentences, front-loaded with core purpose, zero waste. First sentence states what it does, second clarifies what it returns vs. doesn't. Every sentence earns its place by adding clarity.

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 read operation with 3 parameters, 100% schema coverage, and no output schema, the description is adequate but incomplete. It lacks output format details (e.g., integer count, error responses) and behavioral context (e.g., network defaults, error handling). With no annotations, it should do more to compensate.

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%, so parameters are fully documented in the schema. The description adds no additional parameter semantics beyond what's in the schema (e.g., it doesn't explain parameter interactions or provide examples not in schema). Baseline 3 is appropriate when schema does the heavy lifting.

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 ('Get the total number of NFTs owned'), the resource ('by an address from a specific collection'), and distinguishes from siblings by specifying 'returns the count of NFTs, not individual token IDs' (differentiating from tools like get_nft_info or check_nft_ownership that might return different data).

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 'from a specific collection' and clarifies what it returns vs. doesn't return, but doesn't explicitly state when to use this tool vs. alternatives like get_erc1155_balance or check_nft_ownership. No explicit exclusions or prerequisites are mentioned.

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