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

The annotations already establish that this is a read-only, non-destructive operation in a closed world. The description adds that the response includes the ad creative, which is useful return-content context, but it does not address not-found behavior, permissions, or other operational details.

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, front-loaded sentence with no filler. Every element ('single', 'by ID', 'including creative') contributes meaning.

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 simple two-parameter read tool with full schema coverage and annotations covering the safety profile, the description is nearly complete. It states the resource, lookup key, and a notable return attribute; only edge-case behavior such as missing IDs is omitted.

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 coverage is 100%: both required parameters (domain_id and ad_id) are documented in the schema. The description reinforces that lookup is by ad ID but adds no format, constraints, or domain-scoping detail beyond what the schema already provides, so baseline 3 is appropriate.

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?

The description gives a specific verb and resource ('Get a single ChatGPT Ads ad by ID') and adds that the creative is included. The word 'single' implicitly contrasts with the sibling list-openai-ads-ads, and 'including creative' suggests it returns more than the insights siblings, but no sibling is named 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?

The 'by ID' phrasing implies this is for fetching an already-known ad rather than listing or analyzing ads, but there is no explicit statement of when to use this versus list-openai-ads-ads or get-openai-ads-ad-insights, and no exclusions are given.

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