Evaluate Rego with coverage

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

Annotations already signal readOnlyHint=false and openWorldHint=true, so the description's main added behavioral value is clarifying that coverage data is returned per line. It does not discuss side effects, output format details, or interactions with partial evaluation, but it is not misleading.

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 focused sentences convey the core behavior and the intended use case without redundancy. The first sentence states what it does; the second explains why an agent would choose it.

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?

The description is adequate for a familiar Rego evaluation tool: it names the key output (per-line coverage) and the motivating use case. However, with no output schema, an agent would still lack details about the exact coverage result structure and whether normal query results are also returned.

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%, so the schema documents all 8 parameters. The description adds no parameter-level detail beyond indicating coverage is enabled, but that is acceptable because the schema carries the burden.

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 uses a specific verb ('Evaluate') with a clear resource ('Rego with --coverage') and states the distinctive output ('per-line coverage data'). This differentiates it from rego_eval and other evaluation siblings by naming the exact coverage behavior.

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 a clear use case: verifying that tests actually exercise the rules they're meant to. It does not explicitly name alternatives or state when not to use this tool, so it stops short of full routing guidance.

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