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

Annotations cover only readOnly/idempotent/openWorld; the description adds substantial behavior beyond them: the not_found path returns nearest real versions, invented names return lookalike published names, and the Ed25519-signed receipt is offline-verifiable against a published key URL. This is exactly the safety-and-output context annotations cannot carry.

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 the core action and return contract in the first two sentences, which is the right ordering. It runs long with rhetorical asides ('which is the point, because that is how slopsquatting gets installed', 'by someone who was not here') that add flavor but cost tokens.

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 no output schema and a simple two-parameter surface, the description carries the full burden and does so: it explains verdicts, the not_found/lookalike edge cases, and the signed receipt. An agent can call this correctly and interpret the result without further documentation.

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 100%, so both parameters are already documented, including the 'express@4.18.2' syntax and the ecosystem enum with its npm default. The description only restates 'package and version plus its ecosystem', adding no syntax or format detail beyond the schema, so the baseline 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?

States a specific verb and resource ('Reports on a dependency', submit a package/version/ecosystem) and enumerates exactly what the response contains: existence, yanked/deprecated status, and OSV advisories. The 'not a security audit' scope note further sharpens what it is against what an agent might assume.

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 a clear usage context ('at the point of installation') and an explicit exclusion ('Not a security audit'), which steers the agent away from a plausible wrong expectation. It does not, however, name a sibling alternative (e.g. verify_bulk) for batch or other verification needs, so routing is implied rather than stated.

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