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

Adds valuable behavior beyond the readOnlyHint: synchronous execution, free of charge with TPS throttle, and no webhooks/events or outward side effects from rule actions. This materially informs safe invocation.

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?

Three dense sentences, front-loaded with the core purpose and immediately followed by cost and side-effect caveats. No filler or repetition.

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?

For a 2-parameter, read-only operation with no output schema, the description covers inputs, return contents, safety profile, cost, and sync-ness. Nothing essential is missing for selection and invocation.

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 high (both params documented). The description restates the role of traceId and candidateVersionId in context but does not add meaningful parameter detail beyond the schema.

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 names a specific verb and resource ('Re-evaluate a past execution against a candidate version') and specifies what is returned (decision diff plus determinism verdict), clearly distinguishing the action from replay list/status 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?

Provides clear context for use (synchronous, read-only evaluation of a past trace against a candidate version) and adds cost/behavior notes, but does not explicitly contrast with related sibling tools like dry-run or deploy-diff.

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