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 context beyond annotations: it fans out to two external services, mentions that Bundlephobia's first measurement can take 5-30 seconds, and explains how partial failures are reflected (sources_failed list). No contradictions 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 a single long sentence with multiple clauses, making it somewhat dense and harder to parse quickly. While it front-loads the core purpose, breaking it into shorter sentences or bullet points would improve readability. Information is all present but not optimally structured.

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?

Despite lacking an output schema, the description covers the essential return fields (is_latest, license, published_at, advisory_count, bundle_kb_min, bundle_kb_gz, dependency_count, has_esm, tree_shakeable, per-advisory detail, links, recent alternative versions). It also addresses failure modes (sources_failed) and ecosystem limitations, making the tool's behavior fully understandable for an AI agent.

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 parameters are already well-documented. The description adds value by clarifying that 'package' accepts scoped names (e.g., @types/node) and that 'version' defaults to the latest published version. It also summarizes the return shape (summary block, per-advisory detail, links, alternative versions), which goes 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 clearly states it performs a composite check for npm packages, covering license, advisories, version history, and bundle size. It distinguishes itself from sibling tools by explicitly naming the use case and the specific data sources (deps.dev and bundlephobia), leaving no ambiguity about its 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 it: whenever an agent asks about safety, popularity, size, or cost of an npm package. It also specifies limitations (NPM ecosystem only in v1, other ecosystems to be handled via deps.dev:version directly) and mentions graceful degradation for partial failures. This provides clear usage boundaries and alternatives.

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