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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so the safety profile is structured. The description still adds real context: it runs no simulation ("runs nothing"), pages are bounded, and oversized fields are truncated while retaining "exact authorized resource pointers" — output-edge behavior not present in 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?

Front-loaded with the core action and sibling routing in the opening sentences; each sentence carries information. Minor waste in restating read-only ("This is read-only and runs nothing") which the annotations already cover.

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 six-parameter, four-required tool with no output schema and zero schema description coverage, the description covers purpose, routing, and truncation behavior but leaves all parameter semantics unexplained. Adequate to identify the tool, thin for invoking it correctly.

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 0% across six parameters, so the description must carry the burden, yet it never defines baselineBatchId vs candidateBatchId, nor the meaning/range of limit and cursor. Only a faint hint exists via "bounded paired-dimension page," which gestures at pagination without explaining the fields.

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?

States a specific verb and resource with scope: "Compare two authorized batches in the same project/environment," and adds what it returns (matching counts with a bounded paired-dimension page). It explicitly distinguishes itself from firedrill_summary and firedrill_compare_pairs, so an agent can pick it without opening schemas.

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?

Routes the agent away from itself toward siblings: "firedrill_summary for individual populations and firedrill_compare_pairs for every pair rather than summary samples." That is clear alternative selection guidance, though it frames choices around output sampling rather than stating hard when-not-to-use conditions for this tool.

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