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

Goes well beyond annotations (which already indicate safe, idempotent, open-world). Discloses that the tool fans out to two external services, that bundlephobia's first measurement can take 5-30s, and that partial failures degrade gracefully with a 'sources_failed' field. Also describes the return structure with a summary block, advisories, links, and alternative versions.

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 relatively long but efficiently packs critical information. It is front-loaded with the core purpose and then details behavior, return fields, and edge cases. Every sentence contributes meaning, though minor redundancy could be trimmed.

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 of the tool (composite check, multiple sources, partial failures, no output schema), the description is remarkably complete. It lists all returned fields, explains timing behavior, covers scoped packages, and outlines constraints. There are no obvious gaps for an AI agent to misinvoke the tool.

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% with descriptions for both parameters. The description adds value by noting that scoped packages are accepted and that version defaults to the latest. This enriches the semantic understanding without being redundant with 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?

Description clearly states it's a composite check for 'should I add this npm package' covering multiple dimensions (license, advisories, bundle size, etc.). The verb 'scan' and resource 'dependency' are specific, and the description distinguishes from siblings by focusing on npm packages with a combined analysis.

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: 'whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me"'. Also specifies limitations: NPM ecosystem only in v1, and redirects to deps.dev directly for other ecosystems. Provides clear context for alternatives.

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