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

Discloses substantial behavior beyond the readOnly/openWorld/idempotent annotations: it fans out to two external services, includes both license/advisory and bundle-size data, returns a specific summary block and per-advisory details, degrades gracefully on partial failure, and calls out the 5-30s first-measurement timeout. 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 dense but every sentence earns its place: composite purpose, use cases, return contents, ecosystem scope, and timeout/failure behavior. It is front-loaded and structured appropriately for a complex multi-source tool.

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 carries the burden of explaining the return value, and it does so with a field list, per-advisory detail, links, and alternative versions. It also covers failure modes, ecosystem limits, and timing behavior, making it complete for an agent to select and invoke 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?

Schema coverage is 100%, so the baseline is 3. The description does not add parameter-level semantics beyond the schema; it mentions package names and versions only in the context of outputs and limitations, not additional syntax or format details.

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 uses a specific verb+resource ('Composite check whether to add this npm package') and clearly distinguishes itself from siblings by naming the underlying sources (deps.dev and bundlephobia) and the question it answers. It is far more specific than the generic title.

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 states when to use: 'Use whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me".' It also gives an exclusion/alternative: NPM-only in v1, with PyPI/Maven/Cargo/Go falling under deps.dev:version directly.

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