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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuine context beyond that: it names the external data source (OSV.dev) and the shape of the returned intelligence (summary, CVSS, affected package versions, references), which matters since there is no output schema. It does not mention failure behavior for unknown IDs or rate limits, so it is not a full 5.

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, zero filler: the first delivers capability and return shape, the second delivers the routing decision. The capability statement is front-loaded and the alternative is placed last where it is easy to act on.

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?

For a one-parameter, idempotent read tool with full annotation coverage and no output schema, the description supplies everything an agent needs: the identifier space, the data source, the returned fields, and the decision rule against the nearest sibling. Nothing material 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?

Schema coverage is 100%: the single 'id' parameter is already documented in the schema with the same CVE/GHSA/OSV framing the description gives. The description adds no format restrictions (exact prefix syntax, case sensitivity, accepted aliases) 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 (looks up) and resource (a vulnerability by OSV identifier) and enumerates what is returned: summary, CVSS severity, affected packages and versions, references. It also names the sibling it is not (vulnerability_check), so an agent can distinguish the two without opening either 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?

Explicit routing rule: 'Use when you already have an ID; use vulnerability_check when you have a package name instead.' This gives both the when-to-use condition and the named alternative with the condition that selects it, leaving nothing to inference among 40 siblings.

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