npm_signing_keys

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, which fully convey the safe, non-mutating behavior. The description adds context that the keys are ECDSA and used for signature verification, but it does not provide additional behavioral details such as return format or authentication requirements. Given strong annotation coverage, this is adequate but not exceptional.

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 entire description is a single, focused sentence: 'Get the npm registry's ECDSA signing keys used to verify package signatures.' Every word contributes to the meaning, with no redundancy or extraneous detail.

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 simple, no-parameter, read-only metadata retrieval tool with comprehensive annotations, the description is fully sufficient. The lack of an output schema is not a gap because the purpose is straightforward and the strong annotations cover safety and side-effect expectations.

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 tool has zero parameters, and the schema's 100% coverage trivially satisfies parameter documentation. The description naturally implies a no-input fetch. The baseline for zero parameters is 4, and the description adds no additional parameter-related semantics, which is acceptable.

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 tool retrieves the npm registry's ECDSA signing keys used for package signature verification. This specific verb+resource phrasing distinguishes it from all sibling tools, which focus on other aspects like packages, auth, or registry statistics.

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 when to use the tool (when signing keys are needed to verify package signatures) and there are no similar sibling tools that would require explicit differentiation. However, no explicit exclusions or alternative tool references are given, so it falls short of a perfect score.

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