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

No annotations are provided, so the description carries the full burden. It does disclose that envClass is mandatory and that the optional thresholds override default regression gates, which is real behavioral context. However, it says nothing about permissions, side effects, or what the comparison returns (pass/fail vs. metric deltas), leaving the safety and outcome profile thin.

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 with the two selection modes and the required parameter front-loaded; nothing is padding. Slightly compressed phrasing ('max p95 regression percent') costs a little readability but not much space.

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 9-parameter tool with no annotations, no output schema, and no schema descriptions, the description covers the core comparison semantics but omits four parameters and the result shape. An agent can call it, but cannot confidently interpret the outcome or know which optional params matter.

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 9 parameters, so the description must compensate. It explains runId, testchimpId, envClass, maxP95RegressionPercent, and maxFailRateIncrease, but leaves dataset, llmMode, profile, and environment entirely undefined, and never states that runId and testchimpId are mutually exclusive alternatives.

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 (compare) and resource (a run or filtered target vs. its promoted baseline), and names the key identifiers (runId, testchimpId). It is distinguishable from siblings like get-perf-run or promote-perf-baseline, though it never explicitly contrasts itself with them.

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?

It implies two invocation modes (runId, or testchimpId plus optional dimensions) and flags envClass as required, which is useful context. But it never says when to prefer this tool over get-perf-run, list-perf-baselines, or fetch-execution-report, and gives no exclusions or prerequisites.

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