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

Annotations already indicate read-only, open-world, idempotent, and non-destructive behavior. The description adds significant behavioral context beyond those flags: it fans out across two services, partial failures degrade gracefully, and bundlephobia's first measurement can take 5-30s and be reported in sources_failed. This is rich transparency about edge-case behavior without contradicting the 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 long but well-structured: a clear purpose statement, explicit usage trigger, compact summary of return fields, ecosystem scope, and a failure-mode note. Every sentence contributes essential information, though the density might be slightly high for quick parsing. Still, it avoids redundancy and is well front-loaded.

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 composite tool with no output schema, the description fully covers the return structure (summary block fields, per-advisory detail, links, alternatives), the sources used, ecosystem limitations, and failure behavior. It also explains what happens on partial failures. This gives an agent everything needed to use the tool correctly without further inference.

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 both parameters are already described (package and version). The description adds meaningful nuance: 'version' defaults to the latest published version when omitted, and clarifies that 'package' expects npm package names (including scoped ones). This reinforces semantics but does not add new parameters or values.

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 the tool is a composite 'should I add this npm package to my project' check, naming specific sources (deps.dev, bundlephobia) and listing output fields. It distinguishes itself from siblings by being the only package-dependency analysis tool, and also clarifies the NPM-only scope and fallback to deps.dev:version 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?

The description explicitly gives when to use it: 'Use whenever an agent asks...' with concrete example questions. It also provides exclusion guidance: 'NPM ecosystem only in v1; PyPI / Maven / Cargo / Go fall under deps.dev:version directly.' This tells the agent exactly when to use this tool vs alternatives.

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