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

The description richly discloses behavior beyond the annotations: it details what data is returned (summary block, per-advisory details, links, alternatives), explains partial failure behavior, notes that bundlephobia first measurement can take 5-30s, and specifies the ecosystem limitation. This greatly exceeds the annotation hints (readOnly, idempotent, non-destructive) and provides actionable operational context.

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 longer than the calibration examples, but it is information-dense and each phrase adds value: purpose, use case, return payload, limitations, and failure mode. The structure is logical and front-loaded with the core purpose. Slightly verbose for a tool description, but appropriate for the tool's complexity.

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?

With no output schema, the description fully explains the return structure, including the summary block fields, per-advisory detail, links, and alternative versions. It also covers operational caveats like partial failures and timeout behavior, making it complete for an agent to use the tool effectively in a complex scenario.

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 coverage is 100%, so the parameters are already well-defined in the schema. The description adds a few semantic hints, such as the npm-ecosystem scope and that version defaults to latest, but these are already in the schema. It does not materially extend parameter understanding beyond the schema.

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 states a clear, specific purpose: a composite 'should I add this npm package' check that fans out across deps.dev and bundlephobia. It names the exact resources and data points, and it is clearly distinct from sibling tools that focus on searches, visibility, or entity resolution. The verb 'scan' and the resource 'dependency' are well-defined.

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 explicitly states when to use the tool: 'Use whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me".' It also provides an exclusion/alternative: for PyPI/Maven/Cargo/Go, use deps.dev:version directly. This gives clear decision guidance versus alternatives.

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