direct_update_adgroup_regions

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

With no annotations, the description carries the full burden. It does disclose that this is a write operation, that the region list is absolute, and that allow_write=true is required, but it does not explicitly state that existing regions will be overwritten (though 'absolute' implies it), nor does it mention permission requirements or the dry_run behavior that is present in the schema.

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?

The description is extremely concise: one sentence with an example, leading with the operation type 'WRITE'. Every element earns its place, and the example adds immediate clarity without redundancy.

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?

The description covers the essential purpose and the safety flag, but given no output schema and no annotations, it should more explicitly mention the replacement behavior and note that dry_run returns a plan. The example helps, but the tool is a mutation that would benefit from a bit more context about side effects and return format.

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?

The description maps to core parameters via 'specific ad groups' and 'RegionIds', and the example clarifies that negative integers denote negative regions. However, it does not explain dry_run or project, and with schema description coverage at 50%, the description only partially compensates for the missing parameter documentation. allow_write is mentioned explicitly, but dry_run remains undocumented in the description.

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 clearly states 'WRITE: set absolute RegionIds on specific ad groups (positives + negatives)' with an example [225,-11010]. It identifies the verb (set), resource (ad group regions), and scope (absolute, including positive and negative IDs), which distinguishes it from sibling tools like direct_set_region_excludes and direct_get_group_negatives.

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 implies when to use the tool (to set absolute region IDs on ad groups) and mentions the allow_write=true requirement, but it does not explicitly contrast with alternative tools or state exclusions. There is no 'when not to use' guidance, leaving the usage context only implied.

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