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

Annotations already provide readOnlyHint, idempotentHint, and non-destructive. The description adds significant behavioral context beyond that: composite fan-out across two services, partial failure degradation, bundlephobia first measurement latency (5-30s), and the sources_failed field. It also enumerates the returned summary fields. This fully discloses the tool's behavior in edge cases.

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 dense but well-structured. It opens with the core purpose, then explains the fan-out, use case, return fields, limitations, and failure behavior. Each sentence adds value, though the length is above minimal. The information is front-loaded and logically ordered, making it easy to scan.

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?

The tool is composite and has no output schema, so the description must compensate. It covers the ecosystem limitation (NPM only), alternative for other ecosystems, the return summary block fields, per-advisory detail, links, recent versions, and graceful degradation on bundlephobia timeout. This is complete enough for an agent to understand and invoke the tool correctly without further discovery.

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 has 100% description coverage for both parameters. The description does not add new semantics beyond what the schema already states (npm package name, version defaults to latest). The mention of scoped packages is already in the schema. Therefore, baseline 3 is appropriate since the schema carries the parameter meaning.

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 a specific action: 'Composite "should I add this npm package to my project" check in ONE call'. It identifies the resource (npm package) and distinguishes itself from siblings like scan_competitor_ai_presence via the specific use case. The verb 'scan' and noun 'dependency' are precise.

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: 'Use whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me"'. Also gives an alternative: 'PyPI / Maven / Cargo / Go fall under deps.dev:version directly', clarifying the NPM-only scope and directing to a different tool. This is clear when-to-use and when-not-to-use.

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