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

Annotations already declare readOnly, openWorld, idempotent, non-destructive. Description adds critical behavioral insights: partial failures degrade gracefully, bundlephobia first measurement can take 5-30s, sources_failed will list timeouts, and returns summary blocks, advisories, links, and alternatives. This goes well beyond annotation payload.

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?

Description is dense but well-structured: front-loads purpose, then usage, then behavioral details. Each sentence earns its place. Slightly long but not unnecessarily so. Could be tightened slightly but remains effective.

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?

For a composite tool with no output schema, the description fully documents the return structure (summary block, per-advisory detail, links, alternative versions). Paired with 100% schema coverage and complete annotations, an agent has sufficient information to select and invoke the tool correctly.

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 covers both parameters with descriptions (100% coverage). Description adds that scoped packages (e.g., @types/node) are accepted and that version defaults to the latest. This extra context justifies a score above baseline 3.

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 it is a composite check for adding an npm package, fanning across deps.dev and bundlephobia. The verb 'scan' and resource 'dependency' are specific, and the target ecosystem (npm) is explicit. No sibling tool performs this function, so differentiation is inherent.

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, or cost of adding an npm package. Also states NPM ecosystem only in v1 and mentions alternative for other ecosystems (deps.dev:version directly). Provides clear context for invocation.

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