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

Annotations already indicate readOnly, idempotent, non-destructive. Description adds crucial behavioral details: partial failures degrade gracefully, bundlephobia first measurement can take 5-30s, and sources_failed will list if it times out. 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 informative but slightly lengthy. It is well-structured: front-loads purpose, then usage, then return summary, then limitations. Every sentence adds value, though some detail could be more concise.

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 no output schema, the description fully details the return structure: summary block with specific fields, per-advisory detail, links, and alternative versions. Parameter coverage is complete. The description leaves no ambiguity about what the tool returns.

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 both parameters. Description adds value by explaining the default behavior for version (latest) and accepting scoped packages (e.g., '@types/node'), which goes beyond the schema.

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 npm packages using deps.dev and bundlephobia, answering safety, popularity, and size questions. It distinguishes from siblings by noting it covers multiple checks in one call, while other tools like deps.dev:version handle other ecosystems.

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 states when to use: when agent asks about safety, popularity, size, or cost of adding an npm package. Also specifies when not to use: only npm ecosystem in v1; other ecosystems (PyPI, Maven, etc.) fall under deps.dev:version directly.

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