Explain Rego decision

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

Annotations already indicate read-only, non-destructive, idempotent behavior. The description adds that evaluation is with full tracing and the output is a structured trace plus summary, and that the agent narrates without re-implementing parsing. This goes beyond annotations.

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 sentences: first states what the tool does (verb+resource+output), second gives usage and agent behavior. No wasted words, front-loaded with key info.

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 8 parameters and 100% schema coverage, the description explains the output and usage context. However, it could briefly mention mutual exclusivity of source/paths or partial vs full evaluation, but schema already does that.

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%, so baseline is 3. The description doesn't add parameter-specific details beyond what the schema already provides. It mentions 'full tracing' but that's about the tool's mode, not parameter meanings.

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 evaluates a Rego query with full tracing and returns a structured trace plus per-rule summary, specifically for answering 'why was this denied?'. This verb+resource combination is distinct from siblings like rego_eval (no tracing) or rego_explain_undefined (focused on undefined).

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?

Explicitly says 'Use this when you need to answer "why was this denied?"', providing clear context. While it doesn't list when not to use, the surrounding sibling tools imply alternatives (e.g., rego_eval for normal evaluation).

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