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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is known. The description adds valuable behavioral details beyond annotations: versions are returned newest-first, and it includes package created/last-modified timestamps, which is not present in the schema or 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 two sentences, front-loaded with the core action, and uses a parenthetical to list user questions without bloat. Every sentence contributes meaning, and there is no redundant restating of the tool name or schema.

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 simple 2-parameter tool with strong annotations and 100% schema coverage, the description is fully adequate. It explains what the tool returns, the ordering, and its intended use cases. No output schema is present, but the description already mentions the key output elements (versions, dates, dist-tags, deprecation notices, timestamps), so nothing is missing.

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?

The input schema has 100% description coverage: name is described as an exact package name with examples, and limit has a clear default and max. The description adds no further parameter semantics, so the baseline score of 3 applies.

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 and resource ('List published versions of an npm package') and clearly states the delivered fields (publish dates, dist-tags, deprecation notices). It also names the exact user questions it answers, which effectively distinguishes it from siblings like get_version_info or get_package.

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 gives clear usage context by listing the questions the tool answers ('what versions exist', 'when was last published', 'is latest deprecated'). It does not explicitly name alternative tools or when not to use it, but the provided use cases are sufficient for an agent to select it appropriately.

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