npm_package

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

Annotations already convey read-only, idempotent, and non-destructive behavior. The description adds useful scope limitations: what fields are returned and that per-version details are excluded. This goes beyond the structured hints, though it stops short of describing potential errors or rate limiting, which are not critical for this simple read operation.

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 compact sentences: the first leads with the verb and resource, the second clarifies the scope exclusion. No filler words, clear punctuation, and front-loaded purpose.

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 single-parameter, read-only tool with no output schema, the description is sufficient. It lists the return fields, clarifies what is not included, and points to the right alternative. No other contextual gaps exist for the agent to invoke it correctly.

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 schema already provides 100% coverage of the single 'name' parameter, including an example. The tool description adds no further parameter-level semantics. The baseline of 3 applies since the 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 'Get package metadata' and enumerates specific fields (description, dist-tags, latest version, maintainers, license, repository, keywords). It also explicitly distinguishes itself from npm_version by noting it does not include per-version details, which pins down its unique purpose among siblings.

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 explicit when-not-to-use guidance ('Does not include per-version details') and names the alternative tool ('use npm_version for that'). This tells the agent exactly when to choose this tool over its sibling.

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