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

Annotations already indicate read-only, idempotent, open-world, non-destructive. Description adds significant behavioral context: composite nature, partial failure modes, bundlephobia first-measurement delay of 5-30s, sources_failed field. No contradictions with annotations.

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?

Description is information-dense but well-structured. First sentence states core purpose and services. Later sentences add usage guidance, ecosystem scope, and failure behavior. Slightly long but every sentence adds value; could be broken into clearer sections but is not overly verbose.

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?

Despite no output schema, description lists return fields explicitly: summary block fields, per-advisory detail, links, recent versions. Also covers partial failure and list of failed sources. Missing exact structure of nested fields for advisories, but overall sufficient for an agent to understand what to expect.

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% (both parameters described). Description adds value by clarifying that scoped packages are accepted for 'package' and that version defaults to latest when omitted. These are useful nuances beyond the schema descriptions.

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?

Clearly states it's a composite check for npm packages using deps.dev and bundlephobia. Distinguishes itself as a one-call solution for evaluating 'is X safe/popular/small' and specifies ecosystem limitation to npm in v1, with alternatives for other ecosystems.

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?

Explicitly says use when agent asks about safety/popularity/size or cost of adding a package. Mentions ecosystem boundary and alternatives for non-npm ecosystems. However, does not compare directly with sibling tools like 'validate_claim' or 'entity_profile', though the specific use case is distinct enough.

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