Update an ad (name, status, creative, destination URL)

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

The description discloses the most important non-obvious behavior: it is a write that runs as a dry run unless confirm: true is passed, which annotations (readOnlyHint=false, openWorldHint=true) do not convey. It does not disclose whether the update is a partial merge, whether null values clear fields like creativeId/destinationUrl, or whether idempotency is otherwise enforced.

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?

Two tight sentences, with the write/dry-run warning front-loaded where it matters most. The parenthetical field list duplicates the title almost verbatim, which is the only wasted space.

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 nested-body mutation tool with no output schema, the safety model is covered, but the semantics of the nested object are thin: platformNative is unexplained and null-handling on creativeId/destinationUrl is unstated, leaving an agent unsure whether passing null clears or ignores a field.

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 50%; confirm and idempotencyKey are already documented in the schema, and the description's 'set confirm: true' largely repeats that. It names four of the five body fields but omits platformNative entirely, and adds no meaning about nullable fields or merge semantics beyond the schema.

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 ('Update an ad') and enumerates the mutable fields (name, status, creative, destination URL), plus the underlying endpoint PATCH /v1/ads/{id}. That is enough to distinguish it from ads_create and ads_list, though the sibling adGroups_update is never acknowledged.

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?

There is no explicit when-to-use guidance, no statement about which existing ads are eligible, and no contrast with ads_create or adGroups_update. The only procedural guidance is invocation mechanics (dry run by default), not tool selection.

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