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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered by structured data. The description still adds real value by clarifying that the lookup hits live npm state ('exists on npm today', implying results are not cached or stale) and that browser entry points come back. That is useful beyond the annotations, but there is no mention of error behavior for nonexistent packages or network/rate-limit considerations for an open-world call.

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?

Two sentences with the core behavior first and the usage directive second. No redundant restatement of the title or name, and every clause adds information.

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, return values need not be enumerated, and the description still previews that browser entry points are included. Combined with annotations covering side-effect profile, this is nearly complete for a two-parameter read tool; only failure modes for unknown packages are left implicit.

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%, and the description largely restates the schema's own wording (exact version, dist-tag, semver range). It does not explain precedence when both a range and a tag could apply, or how pre-release versions are treated. Baseline 3 is appropriate since the schema carries the parameter semantics.

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?

States a specific verb and resource ('Resolve a package name plus exact version, dist-tag, or semver range') plus the scope of the answer ('the version that exists on npm today, with its browser entry points'). It never names a sibling, so an agent cannot tell from the text alone why this beats search_packages, but the purpose itself is unambiguous.

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?

Gives explicit when-to-use guidance by naming the alternative behavior to avoid: 'Use this instead of recalling versions from memory.' That is a clear trigger condition. It stops short of saying when NOT to use it or pointing to search_packages for discovery, so it is strong but not exhaustive.

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