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

Beyond the annotations, the description discloses compound behavior: metadata fetch plus vulnerability check, and specifies the response fields (isVulnerable/highestSeverity, severity, summary, fixedVersion). It correctly aligns with readOnlyHint=true and destructiveHint=false.

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 carry the full purpose, usage, and output meaning with no filler. The operation is front-loaded before the usage guidance.

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 annotations, complete input schema, and an output schema, the description covers what remains: when to use it, what data it returns, and how findings are represented. Nothing needed for a correct call is missing.

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?

The input schema already fully documents name and version, including length constraints and an example. The description repeats 'exact version' but adds no new semantic detail for either parameter, so the baseline of 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?

The description names the exact operation: fetch registry metadata for one package version and check it against OSV.dev. It makes the resource ('one exact version of a package') and the dual behavior explicit, and separates this tool from any latest-release package lookup.

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?

The description gives a direct usage directive: use this for a version pinned in a lockfile rather than the latest release. It lacks a named alternative tool, so it doesn't fully route the agent to a sibling, but the when/when-not guidance is clear.

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