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

Annotations already declare readOnly (safe, non-destructive), openWorld, and idempotent semantics. The description adds valuable behavioral context: partial failure degradation, bundlephobia's first-measurement timeout (5-30s), and the sources_failed field in the response. This goes well beyond 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 relatively long but well-structured: a front-loaded summary sentence followed by a detailed breakdown of return content, ecosystem scope, and failure behavior. Every sentence provides essential information, though slight tightening could improve conciseness.

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?

No output schema exists, so the description must detail return values. It adequately describes the summary block fields, per-advisory details, links, and alternative versions. It also covers partial failure and timing. However, it does not explicitly list all fields in the summary block, leaving some ambiguity.

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 schema already documents both parameters (package, version) and their defaults. The description does not add new parameter-level meaning beyond confirming that scoped packages are accepted, which is implied by the schema's type. No significant additional semantics are provided.

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?

Description clearly states it performs a composite check for evaluating npm packages, specifying the two data sources (deps.dev and bundlephobia) and the returned metrics. It distinguishes from sibling tools by noting the NPM-only scope and directing other ecosystems to alternative tools.

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 the tool (e.g., 'is X safe/popular/small' or 'what does adding lodash cost me') and provides a clear exclusion — non-NPM ecosystems fall under deps.dev:version directly. This gives agents clear decision boundaries.

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