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

Annotations already indicate read-only, idempotent behavior. The description adds valuable context about the data source (jsDelivr's index), scope (one specific version), and the nature of results (CDN-oriented file tree), which goes beyond the annotations without contradicting them.

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 concise and front-loaded, leading with the core purpose and then detailing return fields and use case. It avoids redundancy and every sentence adds value.

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 an output schema present and simple parameters, the description adequately covers the tool's operation, including the source and the type of data returned. It does not discuss edge cases or prerequisites, but these are not critical for a straightforward read-only 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?

Schema coverage for parameters is 50% (only version has a description). The description indirectly clarifies that package_name is the npm package name and mentions 'latest by default', which addresses version semantics. However, it does not fully describe parameter formats or provide examples, leaving some burden on 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 lists the file tree of an npm package version via the jsDelivr Data API, emphasizing the specific data returned (path, size, hash, type). It distinguishes from siblings like list_npm_versions by focusing on file structure rather than version listings.

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 provides clear context for when to use the tool (to determine what files, entry points, and build outputs a package actually ships), though it does not explicitly name alternative tools or exclusion criteria. This is a minor gap, but the implied use case is unambiguous.

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