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

Beyond the annotations (readOnly, openWorld, idempotent), the description discloses important behavioral traits: it requires the SkimGuard Data Licensee tier, and the server will respond with an authentication challenge if the user is not signed in. It also instructs not to fabricate an answer, which is crucial for agent 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 concise and front-loaded: it starts with the core purpose, then the access requirement, and then practical guidance. Every sentence earns its place with no redundancy.

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 zero parameters and no output schema, the description still provides a complete picture: what data is aggregated, the access tier needed, what happens if not authenticated, and a warning against fabrication. This is fully sufficient for a zero-param read-only tool.

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 tool has zero parameters, so there is nothing to explain about parameters. Per the baseline for 0 params, a score of 4 is appropriate since the description doesn't need to compensate for schema gaps.

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 opens with 'Aggregate PCI POI device-inspection compliance trends' which clearly specifies the action (aggregate) and resource (PCI POI device-inspection compliance trends), and enumerates the exact metrics (pass/fail, tamper-incident, tamper-check failure rates). This distinguishes it from sibling tools like training_stats or coverage_stats.

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 provides explicit when-to-use guidance: 'Call this tool anyway if the user is asking for their own business, reseller, or licensed data'. It also explains the authentication challenge flow. However, it does not mention alternative tools for other cases, 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.