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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered by structured data. The description's 'Changes nothing' line is largely redundant with readOnlyHint, and it discloses nothing about return format, pagination, rate limits, or auth needs, so it adds only the get_tool_schema routing hint.

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?

One compact paragraph, front-loaded with the read-only framing and ending with the actionable get_tool_schema hint. The long operation list duplicates the schema enum, which is mild redundancy, but nothing is wasted or buried.

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 13-operation dispatcher with a nested, undocumented params object and no output schema, the description is thin: it does not indicate what any operation returns or how to pick one. It mitigates this by pointing to get_tool_schema, but an agent still needs an extra call to use the tool competently.

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 0%, so the description must carry parameter meaning. The operation enum values are self-documenting in the schema, but the free-form 'params' object is opaque; the description's note that operation parameters come from get_tool_schema is a genuinely useful pointer, though it stops short of describing expected param shapes.

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 names a specific resource (ChatGPT Ads) and scope (read-only operations), enumerating all 13 supported operations. Combined with the 'read' title, an agent can distinguish it from the write-side sibling openai_ads_changes, though the description never explicitly names that alternative.

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 states 'Changes nothing in the ad account,' which signals a read context, and routes parameter lookup to get_tool_schema. However, it gives no explicit criteria for choosing among the 13 operations or between this tool and alternatives like get_performance or google_ads.

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