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

Annotations already declare read-only and idempotent hints, so the description adds substantial behavioral context: it fans out to two services, returns a specific summary block, degrades gracefully on partial failures, and warns about a 5-30s possible delay for bundlephobia's first measurement. 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?

Every sentence earns its place: purpose, usage triggers, return fields, ecosystem scope, and failure behavior are all covered without redundancy. The description is front-loaded with the core use case and keeps the remaining info tightly packed.

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?

With no output schema, the description fully compensates by listing the exact summary block fields, per-advisory detail, links, and alternative versions. It also covers timing, partial failure behavior, and ecosystem scope, making it complete for a complex composite 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?

Input schema covers both `package` and `version` with descriptions (100% coverage). The description adds no new parameter-level semantics beyond the schema; it only restates npm scope in prose. Per rubric, baseline 3 is appropriate when schema covers fully.

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 uses a specific verb ('scan') and resource ('npm package'), and explicitly labels itself as a 'Composite check' aggregating deps.dev and bundlephobia. It clearly distinguishes itself from sibling tools by naming its cross-service scope and NPM-only ecosystem.

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?

Provides explicit usage triggers ('Use whenever an agent asks "is X safe / popular / small"...') and an explicit exclusion for non-NPM ecosystems, directing users to 'deps.dev:version directly'. This covers both when and when-not to use the tool.

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