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

Beyond annotations (readOnlyHint, idempotentHint), the description reveals important behavioral details: partial failures degrade gracefully, bundlephobia's first measurement can take 5-30 seconds, and sources_failed will list timeout items. 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 well-structured, starting with a clear verb and resource, then detailing return fields, ecosystem scope, and error handling. Each sentence contributes meaningful information; however, it could be slightly more concise by breaking into separate bullet points or paragraphs.

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?

Despite lacking an output schema, the description fully explains the return block fields, error behavior, and timing. With only two parameters and moderate complexity, the description provides complete contextual coverage, leaving no critical 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?

Schema coverage is 100% with descriptions for both parameters. The description adds semantic value by clarifying that scoped packages (e.g., '@types/node') are accepted for 'package' and that 'version' defaults to the latest published version when omitted. This goes beyond the schema basics.

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 the tool's purpose: a composite check for deciding whether to add an npm package, covering safety, popularity, and size via deps.dev and bundlephobia. It distinguishes itself from sibling tools by focusing on npm package evaluation, with no overlapping tools in the sibling list.

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: 'Use whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me".' Also specifies ecosystem scope ('NPM ecosystem only in v1') and directs other ecosystems to deps.dev:version directly, providing clear when-to-use and when-not-to-use guidance.

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