Compare two runs

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

Since no annotations are provided, the description carries the full burden. It discloses the matching key ('stable test id'), the delta categories, and the default run selection logic, adding behavioral context beyond the schema. It does not mention side effects, but this is a read-only comparison so it is not a major gap.

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 two sentences, front-loaded with the primary action, and every clause adds value. It is compact without being under-specified.

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 the tool's moderate complexity (two optional params, no output schema), the description covers the core functionality, output categories, and defaults. It could explicitly describe the return format, but the listed categories imply the response structure.

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 baseline is 3. The description enriches parameter semantics by stating that currentRunId defaults to the latest run and baselineRunId defaults to the most recent earlier run covering the same suites, which the schema does not include.

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 states a specific verb 'Compares' and resource 'two stored runs', and goes beyond by explaining the output categories (regressions, fixed, newFailures, etc.), which clearly distinguishes it from sibling tools like qa_run_* and qa_report.

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 clear context by calling regressions 'the release blocker' and specifies default behavior for run selection. It does not explicitly name alternative tools or exclusions, but the context and sibling tool names make the use case clear.

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