compare_runs

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

With no annotations provided, the description carries the full disclosure burden, and it does surface meaningful behavior: the four categories of comparison output and the non-obvious constraint that the script diff only covers the first two runs. It stops short of stating that this is a read-only/non-mutating operation or any limits on run count or cost.

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?

A single sentence, front-loaded with the verb, then a tight enumeration of outputs. No filler, no restatement of the title, and every clause carries information.

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?

An output schema exists and parameters are fully documented, so the description needn't explain return shapes; what it adds is the right shape of summary for a read-only comparison tool. Minor gaps remain around minimum run count enforcement and error behavior with a single run id.

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 run_ids and code_diff are already fully documented, including the baseline rule and the first-two-runs diff scope. The description restates rather than extends that semantics, which is the defined baseline of 3.

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+resource ("Compare runs") and enumerates exactly what the comparison yields: differing params, metrics, data versions, and a script diff. It is clearly distinct from list_runs, best_run, and run_log. It loses a point only because it never names a sibling to contrast against explicitly.

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?

Usage is implied rather than stated: "params that differ (baseline -> each run)" signals that you supply multiple run ids with the first as baseline, which tells an agent when the tool fits. There is no explicit when-to-use, when-not-to-use, or alternative such as best_run for picking a winner instead of comparing.

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