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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, destructiveHint=false. The description adds valuable context: external APIs are called (deps.dev, bundlephobia), bundlephobia's first measurement can take 5-30s and may time out with sources_failed, and the return format includes summary, advisories, links, and alternative versions. No contradiction.

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 front-loads the core purpose. It is informative but slightly lengthy due to comprehensive detail. Every sentence serves a purpose, but could be trimmed marginally. Still well-structured and efficient.

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 (multiple data sources, partial failure, no output schema), the description covers return value structure (summary block fields, per-advisory, links, alternative versions), limitations (NPM only, bundlephobia latency), and graceful degradation. Fully adequate for an agent to understand behavior.

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 clear descriptions for 'package' (npm package name, scoped accepted) and 'version' (optional, defaults to latest). The description mentions defaulting to latest but adds little beyond schema. Baseline 3 is appropriate; no extra semantic richness.

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 starts with a specific verb-resource combination ('Composite check ... in ONE call') and clearly states the tool scans npm packages for safety, popularity, size, etc. It distinguishes from other tools by explicitly noting NPM-only scope and referencing sibling tools for other ecosystems (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?

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 provides exclusions ('NPM ecosystem only in v1') and alternatives ('PyPI / Maven / Cargo / Go fall under deps.dev:version directly'), plus behavior under partial failures.

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