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

Annotations already cover read-only/idempotent/non-destructive, but the description adds material context the agent cannot get elsewhere: the toll (0.0100, waived when the package does not exist), that the queried name is recorded on a miss, the deterministic risk heuristics applied, and the firm boundary 'metadata only, never a tarball'.

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?

Front-loaded with purpose and cost, then the payload and caveats. Dense and mostly waste-free, though the long parenthetical enumerating risk heuristics is heavier than an agent strictly needs at selection time.

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, so enumerating returned fields and the risk block is a real service, and the pricing/hallucination-list behavior is disclosed. The gap is parameter-level detail: with 20% schema coverage and five parameters, param behavior (especially version and work_token) is left unaddressed.

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 description coverage is only 20% across five parameters. The description names the supported registries (npm, PyPI, crates.io) but never explains the `version` parameter, `work_token`, or how `x_payment` relates to the stated toll; with such low coverage the description should have compensated and does not.

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+resource: it returns registry metadata for an npm/PyPI/crates.io package name, and enumerates exactly what comes back (exists, first published, latest version, maintainers, downloads, licence, repo, risk block). No sibling tool covers package/registry lookups, so it is trivially distinguishable from answer/ask/attest/survey.

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 clear situational context — use it on a package name 'before an install' — and explains the motivating problem (roughly one in five AI-suggested names does not exist). It stops short of naming alternatives or explicit when-not-to-use conditions, but no sibling tool is a plausible substitute.

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