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

The description adds transparency beyond the read-only/idempotent annotations by disclosing composite fan-out behavior, partial failure degradation, and the 5-30s first-measurement timeout with sources_failed reporting. This gives the agent a clear model of what to expect at runtime 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 a single dense paragraph but every sentence carries distinct information: purpose, usage triggers, return fields, ecosystem scope, and failure behavior. It is longer than ideal but the density of new facts justifies the length; a slight structural breakdown into sections would improve scannability but is not required.

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 takes on the responsibility of explaining return values, listing exact summary fields (`is_latest`, `license`, `advisory_count`, etc.), per-advisory details, links, and alternative versions. It also covers edge cases like partial failures and ecosystem limitations, making it fully self-contained for an 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?

The input schema already provides 100% coverage of both parameters (`package` and `version`) with descriptions. The tool description does not add meaningful parameter-level detail beyond what the schema says; it mentions the default version behavior but that is already in the schema. Therefore the baseline of 3 is appropriate.

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 begins with a specific verb and resource: 'Composite "should I add this npm package to my project" check in ONE call' and clearly enumerates the underlying sources (deps.dev and bundlephobia) and outputs (summary block, advisories, links, alternatives). This sharply distinguishes it from sibling tools by describing a unique composite behavior.

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 states when to use the tool: "Use whenever an agent asks 'is X safe / popular / small' or 'what does adding lodash cost me'". It also provides exclusion guidance in 'NPM ecosystem only in v1; PyPI / Maven / Cargo / Go fall under deps.dev:version directly', steering users to an alternative approach for other ecosystems.

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