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

Annotations already provide safety traits; description adds valuable behavioral context: composite fan-out, graceful partial failures with sources_failed, and timing caveat for first measurement (5-30s). No contradictions.

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?

Dense single paragraph that front-loads the key benefit. Efficiently covers purpose, usage, return structure, and limitations without wasted words. Could be slightly more structured but still very good.

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?

No output schema exists, yet description adequately describes return values (summary block, advisory details, links, alternative versions) and partial failure behavior. Covers all critical aspects for a moderately complex 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% (baseline 3). Description adds extra meaning: defaults version to latest, accepts scoped packages, and explains that package is the name and version is optional.

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?

Clearly states the tool is a composite check for npm packages combining deps.dev and bundlephobia data. Distinguishes from siblings by specifying the composite nature and the specific sources, and notes that other ecosystems fall under deps.dev:version directly.

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 says when to use: when an agent asks about safety/popularity/size. Also sets boundaries by stating NPM only in v1. Lacks explicit when-not-to-use alternatives, but the context is clear enough.

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