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

The description discloses rich behavioral details beyond annotations: composite fan-out across multiple APIs, partial failure degradation, the 5-30s first-measurement delay from bundlephobia, and the sources_failed field that reports timeouts. This goes well beyond the readOnlyHint/idempotentHint annotations and provides actionable expectations for the agent.

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 information-dense and front-loaded with the core purpose in the first clause. Every sentence adds value, but the long list of output fields and the lengthy parenthetical about timing make it slightly more verbose than ideal. Still well-structured and efficient for the complexity.

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?

Given the tool's complexity (composite multi-source check, no output schema), the description is remarkably complete: it lists the output summary fields, mentions per-advisory detail, links, and alternative versions, and explains failure behavior under partial outages. It gives enough context for an agent to know what to expect and how to handle anomalies.

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 description coverage is 100%, so the baseline is 3. The description adds minimal parameter-specific meaning beyond the schema: it mentions scoped packages and default version behavior, but these are already in the schema. The parameter semantics are fully handled by the schema, so no extra credit beyond baseline.

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 opens with a specific verb-resource-scope statement: "Composite 'should I add this npm package to my project' check in ONE call" and immediately lists the data sources (deps.dev, bundlephobia). It clearly distinguishes from siblings like scan_competitor_ai_presence by focusing on npm package evaluation with a distinct 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?

Explicit usage guidance is provided: "Use whenever an agent asks 'is X safe / popular / small' or 'what does adding lodash cost me'." It also states an exclusion and alternative: "NPM ecosystem only in v1; PyPI / Maven / Cargo / Go fall 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.