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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world, so the safety profile is fully covered. The description adds real value by describing the return payload (CVE ids, severity, fixing versions, smallest safe upgrade), which matters since there is no output schema. However, it says nothing about behavior for unknown packages, unsupported ecosystems, or empty results.

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, front-loaded with the core question and followed by the return contents; no wasted wording. The question form is slightly less scannable than a declarative verb-resource statement but is compact and purposeful.

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, the description carries the burden of explaining return values and does so adequately in one clause. For a three-parameter read-only lookup it is nearly complete, with only edge-case behavior (no advisories found, unknown ecosystem) 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 coverage is 100% and every parameter already carries a description, including the example values and the PyPI default, so the schema does the heavy lifting. The description's emphasis on 'exact version' marginally reinforces that version must be pinned rather than a range, but adds no new semantics for ecosystem or name.

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?

Names a specific verb-and-resource question ('is this exact version of a package affected by known security advisories') and previews the return content. An agent can distinguish it from node_check or types_check easily, though it doesn't explicitly separate itself from upgrade_check, which superficially overlaps via the 'smallest safe upgrade' output.

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?

Usage is implied by the phrasing 'this exact version of a package' and the required name/version pair, so an agent can infer this is a per-version security lookup. There is no explicit when-to-use vs when-not guidance, no mention of when to prefer a sibling like upgrade_check or package_info, and no prerequisites stated.

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