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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description still adds real behavior beyond that: results depend exclusively on the supplied package list, unsupported ecosystems are silently ignored, and the summary/report outputs are distinguished. It doesn't disclose rate limits or failure modes, so a 4 rather than 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?

Content is front-loaded with a one-line purpose followed by cleanly separated What/When/Ecosystems/Inputs/Outputs/Guidelines sections. It is long, and the ecosystem table plus manifest list are verbose, but each block carries actionable information rather than filler.

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 single-parameter, annotated, read-only tool with an output schema, the definition covers everything an agent needs: when to use it, supported inputs, and what report vs summary contain. Nothing required for correct invocation 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% for the single 'purls' parameter, so baseline is 3. The description adds meaningful semantics beyond the schema — per-ecosystem PURL syntax examples and a mapping of which manifest files (package.json, requirements.txt, Cargo.lock, etc.) each should be generated from, which genuinely helps correct invocation.

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 ('Perform a software package vulnerability audit') and pins the scope to PURL-identified packages backed by SecDB, which clearly separates it from OS-level or feed-oriented siblings like linux_audit and feed_report. An agent can identify what it does and its input domain without opening the 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?

The 'When to use this tool' section gives three concrete triggering conditions (dependency CVEs, advisory impact, patching needs) and even an imperative 'always call this tool' rather than guessing. It lacks explicit 'when not to use' or named alternatives among siblings, so it falls short of a 5.

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