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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds concrete consequences the annotations cannot convey: ENABLED begins spending, PAUSED stops delivery and is reversible, REMOVED is permanent and not undoable via API or the Ads UI. That spend and reversibility detail is genuinely additive.

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 sentences, zero filler, and the operation is front-loaded with the destructive case (REMOVED) clearly distinguished. Every clause earns its place.

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 destructive mutation with no output schema, the description covers the key risks (irreversibility, spend impact) and the schema covers parameters thoroughly. It slightly under-delivers on permission/auth requirements and what the response returns, but nothing critical to a correct call is missing.

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 100%, so the baseline is 3, but the description meaningfully expands the most important enum beyond the schema's terse "REMOVED is irreversible" by spelling out spend behavior for ENABLED and reversibility for PAUSED. The other params (campaignId, customerId, extraFields, validateOnly) are left entirely to the schema, which documents them well.

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?

"Change a campaign's status" is a specific verb+resource, and the title plus enum values make the three operations explicit. It is distinguishable from update_campaign (broader edits) and update_ad_status (different resource) by scope, though it never names those siblings directly.

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 explains what each status means but gives no explicit guidance on when to prefer this over update_campaign or update_ad_status, nor any prerequisites. Usage is implied by the enum semantics rather than stated.

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