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

With no annotations, the description carries the full behavioral burden and does well: it discloses that a null return means the execution is outside the project, that retained=false means no nonempty public answer or ad evidence was captured, and that nulls do not prove no ads were shown. It stops short of stating auth requirements, rate limits, or pagination behavior.

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, then dense but purposeful edge-case semantics. Every clause (null scope, retained=false, nulls-not-proof-of-no-ads) carries information, though the middle section reads as a run-on sequence of caveats.

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?

No output schema and no annotations, so the description must stand alone; it covers the action, the input source, the return shape (sponsored ads labelled separately from organic answer), and the important null/retained semantics. Only the exact response fields and permission requirements are left implicit.

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% for the single executionId parameter, so the description must compensate. It adds real value by stating the provenance of the id (from the response history or recent responses list), which the schema's bare uuid format does not convey.

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 ('Read one AI execution') and clarifies the scope ('using an executionId from the response history or recent responses list'). It also names the sibling it is not ('Use visibility summary for rollup-backed advertising rates'), so an agent can distinguish it from the rollup and list tools without opening any schema.

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?

Tells the agent where the required input comes from (response history / recent responses list) and routes rollup use cases to a named alternative (visibility summary). Both the selection condition and the alternative are explicit, leaving little to inference.

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