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

Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds critical behavioral context: fans out to two services, bundlephobia first measurement can take 5-30 seconds, and partial failures degrade gracefully with a list of failed sources. No contradictions 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 dense and front-loaded with the core purpose. While long, every sentence adds meaningful information. Could be slightly more structured, but it is efficient for the complexity of the tool.

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, but the description thoroughly details the return structure: summary block with specific fields, per-advisory detail, links, and alternative versions. Also covers edge cases like partial failures and timing. For a tool with 2 parameters and complex output, this is highly complete.

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 100% description coverage. The description adds context: scoped packages are accepted for 'package', and 'version' defaults to latest when omitted. This adds value beyond the schema definitions.

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 is a composite check for npm packages, answering questions about safety, popularity, and size. It explicitly lists the resources consulted (deps.dev and bundlephobia) and the use cases, distinguishing it from any sibling tools.

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?

Explicit usage guidance: 'Use whenever an agent asks "is X safe / popular / small" or "what does adding lodash cost me"'. Also specifies limitations: 'NPM ecosystem only in v1' and mentions alternative tools for other ecosystems. Describes behavior on partial failures.

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