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

Beyond readOnlyHint/openWorldHint, it discloses that no authentication is required and that untracked packages are fetched live on the first call — non-obvious side-effect behavior an agent should anticipate. It also maps withdrawal semantics per ecosystem (npm deprecated, PyPI/crates yanked, Packagist abandoned), which is behavioral context the annotations cannot convey.

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 output content, behavior disclosures and sibling routing are all front-loaded and each sentence earns its place. The first sentence is dense with field enumerations, but it is information the agent needs rather than filler.

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?

There is no output schema, and the description compensates by enumerating the returned fields and the maintenance summary, plus the ecosystem-specific withdrawal vocabulary. Combined with the auth and live-fetch disclosures, an agent has everything needed to call and interpret the response.

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%, so ecosystem, name, limit and stable_only are already fully documented in the schema; the description adds no format or syntax details for them. Baseline 3 applies because the schema carries the parameter burden.

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 names a specific verb and resource ('Lists the published versions of one package, newest first') and immediately enumerates the returned fields. It explicitly differentiates itself from siblings package_status and version_status, so an agent can route correctly without opening a schema.

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?

It gives three concrete use cases (judge release cadence, see which version was current at a date, check withdrawal status) and names both alternatives with the condition that selects each. Nothing is left to inference.

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