OPA capabilities

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

The description discloses important behavioral traits beyond the annotations: it explains the response size limit rationale for names_only default, what data is returned in each mode, and the trade-off of setting names_only to false. This adds substantial context the annotations alone do not provide.

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 (3 sentences) and front-loaded with the core purpose in the first sentence. Each subsequent sentence earns its place by describing parameter modes and default behavior. No filler or 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?

Given three optional parameters and no output schema, the description provides enough context: it explains the return content, the version-specific behavior, and the names_only trade-off. It does not detail the output format, but this is not critical given the clarity of the content description.

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 covers all three parameters with detailed descriptions (mutual exclusivity, default behavior, response size rationale). The description repeats much of this information without adding new meaning, so it neither enhances nor detracts from the schema's coverage. Baseline 3 is appropriate since schema coverage is 100%.

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 a specific verb and resource: 'Return OPA capabilities' followed by a clear breakdown of contents (builtins, future keywords, features, WASM ABI versions). This clearly distinguishes it from sibling Rego/OPA tools, which focus on formatting, parsing, testing, or policy operations.

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 explicit conditional usage for each parameter combination: 'With current: true...', 'With version...', 'With neither...'. It also explains the names_only default and how to override it. While it does not explicitly name alternatives or exclusions, the parameter-driven guidance is clear and actionable.

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