Update an ad group (name, status, budget, targeting, bid)

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

Annotations only declare readOnlyHint=false and openWorldHint=true; the description adds the genuinely non-obvious fact that calls are dry-run unless confirm:true is passed, which prevents accidental live mutations. It stops short of saying whether omitted body fields are preserved (PATCH merge) or cleared, and what the dry-run preview returns.

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 short sentences, front-loaded with the action and the write-safety caveat, with no filler. The opening phrase duplicates the tool title verbatim, which is minor waste but not harmful.

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 mutation tool with a deeply nested body (bid strategies, budget types, targeting arrays) and no output schema, the description covers the safety mechanism but not update semantics, validation behavior, or what a dry-run returns. Adequate but leaves real gaps an agent would need to guess at.

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 50%: confirm and idempotencyKey are documented in the schema itself, while id and body are not. The description lists the body fields (name, status, budget, targeting, bid) but only mirrors the schema's property names without adding format, currency/micros semantics, or partial-update behavior. 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?

States a specific verb and resource ("Update an ad group") plus the concrete mutable fields and the underlying PATCH route, so the agent knows exactly what is being modified. It does not distinguish itself from siblings such as adGroups_create or campaigns_update, leaving that to the tool name alone.

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 description gives clear execution guidance (dry run by default; confirm: true to execute), which is the most common failure mode for write tools. However, it offers no guidance on when to choose this over adGroups_create or campaign-level updates, and no prerequisites or exclusions.

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