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

The description adds significant behavioral context beyond annotations: partial failures degrade gracefully, bundlephobia's first measurement can take 5-30 seconds, and sources_failed lists timeouts. Annotations already indicate read-only and idempotent, but the description enriches with real-world runtime behavior. No contradiction 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?

The description is concise yet comprehensive, front-loading the key composite check purpose. Every sentence adds value: ecosystem, return fields, delay warning, alternative for other ecosystems. No wasted words, and the structure is easy to scan.

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?

Given the complexity (composite of multiple sources), full schema coverage, and rich annotations, the description covers all necessary context: return fields, partial failure handling, timing, ecosystem scope. No output schema exists, but the description lists the returned fields explicitly, making it self-contained.

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% for both parameters (package and version). The description adds that version defaults to latest and accepts scoped packages (e.g., @types/node). This provides minimal added value beyond the schema, warranting a baseline score of 3.

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 it performs a composite check for adding an npm package, covering license, advisories, version history, bundle size, and tree-shaking. It distinguishes itself from sibling tools by specifying the ecosystem (NPM) and referencing the underlying services (deps.dev, bundlephobia). This specificity ensures the agent understands the tool's unique purpose.

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 tells when to use: when an agent asks about package safety, popularity, or size, e.g., 'is X safe / popular / small' or 'what does adding lodash cost me'. It also notes limitations (NPM only) and directs to alternatives for other ecosystems (PyPI, Maven, Cargo, Go). This provides clear context for tool selection.

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