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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds non-obvious behavioral context: the tool does not merely return one run, it aggregates lineage including derived boosts and a combined cross-lineage readout. It does not mention auth or rate-limit constraints, so it is not a 5.

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 sentences, front-loaded with the core purpose before the usage cue, and the Returns block is compact. The inline Returns object is dense but earns its place given there is no output schema; nothing is redundant.

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?

With no output schema, the description usefully supplies the return shape (run, lineage with rootRunId, bestCompletedRunId, overallReadout, runs, activeBoostRunId), which an agent needs. Annotations cover the safety profile. The remaining gap is unaddressed parameter meaning, preventing a 5.

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% and all three params (ideaId, runId, response_format) are undocumented in schema. The description says 'one Ad Run' and 'the original run,' weakly implying runId, but never explains ideaId's role, the relationship between ideaId and runId, or the markdown/json response_format enum. It fails to compensate for the coverage gap.

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 (Get) and resource (one Ad Run) and scopes it precisely to 'full lineage — the original run, any boosts derived from it, and the combined readout.' This clearly differentiates it from siblings like idealaunch_list_ad_runs (plural listing) and idealaunch_get_run_events (events).

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?

Explicitly states when to use it: 'when the user wants the detail behind a single experiment, including how boosts compare to the original.' The 'one Ad Run / single experiment' framing implicitly distinguishes it from the list tool, but no alternative is named as an exclusion, so it falls short of a 5.

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