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

Annotations already declare readOnlyHint, destructiveHint, idempotentHint, and openWorldHint, so the safety profile is covered. The description adds valuable context: data sources (OSV.dev, deps.dev, PyPI, npm), refresh policy ('data refreshed on each call'), rate limit (30/minute), and no-auth requirement. This goes beyond annotations and helps agents anticipate behavior.

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?

The description is dense but well-structured, front-loading the core verdict and then detailing return fields, constraints, and use case. The feedback instruction is extra but useful for agents. No redundancy, though it could be trimmed slightly without losing value.

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 an output schema present, the description does not need to explain return values but still lists them for clarity. It covers rate limit, auth, use case, and data refresh. It even provides a fallback (report_feedback) if the tool does not serve the user. No critical gaps for an agent to call it correctly.

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% – all three parameters (package_name, ecosystem, version) have clear descriptions with examples. The description adds no new parameter-level meaning beyond what the schema already provides. Baseline 3 applies since the schema carries the load.

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 clearly states it provides a single SHIP/CAUTION/BLOCK verdict combining CVEs, licence, maintainer health, and transitive count. It distinguishes itself from more granular siblings like security_fetch_package_vulnerabilities by offering a consolidated risk brief. The verb 'fetch' and resource 'package risk brief' are specific and unambiguous.

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?

It explicitly targets security engineers performing pre-inclusion package review, giving a clear context. However, it does not name specific alternatives or state when to prefer this over the granular tools (e.g., security_fetch_package_licence). The guidance is adequate but lacks explicit exclusions or comparisons.

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