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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds genuinely non-structured behavior: the call is a dry-run unless 'confirm' is true, which is the key fact an agent needs to avoid unintended changes.

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?

Three short sentences, front-loaded with the action, followed by the ID sourcing prerequisite and the preview condition. Every clause carries information; nothing is padding.

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 no output schema, the description covers the action, the identifier provenance, and the preview/confirm gate, which is most of what an agent needs. It stops short of describing what the preview returns or any permission requirements.

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 only 20% (only 'confirm' is documented in the schema), so the description must compensate, and it partially does by explaining where ad_group_id and criterion_id come from. However, customer_id is never explained and the description does not state the allowed status values, leaving gaps relative to the 5-parameter surface.

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?

Opens with a specific verb set and resource: 'Pause, enable or remove one keyword.' This clearly separates it from the sibling status tools ads_set_ad_status and ads_set_campaign_status, which operate on different resources, so an agent can select it without opening the schema.

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 tells the agent where to obtain the two required identifiers ('Get ad_group_id and criterion_id from an ads_report query on the keyword_view resource') and states the preview-by-default condition. It does not name an explicit alternative or when-not-to-use this tool, which keeps it short of a 5.

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