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

Annotations already mark it as read-only, idempotent, and non-destructive. The description adds valuable behavioral context: composite nature (fans out across sources), partial failures (graceful degradation), timing (bundlephobia first measurement takes 5-30s), and error reporting (sources_failed list). No contradiction 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 paragraph that efficiently conveys purpose, usage, behavior, and output. It is front-loaded with the main goal. While dense, every sentence earns its place and there is no redundancy. A slightly more structured format (e.g., bullet points) could improve readability, but it is still concise.

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 complexity (composite check, multiple sources, partial failures) and lack of output schema, the description completely explains what is returned: a summary block with specific fields, per-advisory details, links, and alternative versions. It also covers ecosystem scope and error handling. No gaps.

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?

Input schema covers both parameters with 100% description. The description adds clarity: scoped packages like '@types/node' are accepted, and version defaults to latest when omitted. This goes beyond what the schema provides, making it more helpful for an agent.

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 is a composite check for npm packages using deps.dev and bundlephobia, with a specific verb 'scan_dependency' and resource 'npm package'. It distinguishes itself from sibling tools like deep_research or scan_competitor_ai_presence by focusing on package evaluation.

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: 'Use whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me".' It also notes NPM-only scope and mentions fallback to deps.dev for other ecosystems. While it doesn't explicitly list when not to use, the context is sufficient.

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