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

Annotations already declare destructiveHint=true, idempotentHint=true and openWorldHint=true, so the extra value here is the business semantics: PAUSED halts serving, ENABLED resumes serving and can immediately spend budget, and REMOVED is refused. That spend-impact warning is genuine context beyond the annotations. It stops short of describing error behavior or permission requirements.

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 definition is front-loaded with the operation, then the safety constraint, then argument detail — a sensible order with no filler. The clause "at once: it serves again and can spend" is slightly dramatic but carries useful warning content, so it 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?

All four required parameters are addressed, the status domain is bounded, and the destructive scope is clarified, which is enough for an agent to invoke this correctly. Because an output schema exists, the brief Returns note is sufficient; only error/permission behavior is left unstated.

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 0% (only bare titles), so the Args block is carrying the burden and does add real meaning: customer_id must be digits only without hyphens, and status is constrained to ENABLED or PAUSED — an enum the schema does not encode. However, ad_group_id and ad_id get only restatements of their names, so coverage is uneven across the four required parameters.

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 opening sentence gives a specific verb pair and resource ("Pauses or enables an ad"), and the paragraph clarifies that the mutation is limited to serving status, never deletion. It distinguishes implicitly from campaign- or asset-level siblings (set_campaign_status, set_ad_group_asset_status) by naming the ad as the target, but never calls out those alternatives explicitly.

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?

Usage is implied by the verb and by the explicit exclusion of status REMOVED, which tells the agent one case where this tool must not be used. There is no statement of prerequisites (permissions, ad type restrictions) and no routing to sibling tools such as update_ad_group, set_campaign_status, or set_ad_group_asset_status for adjacent tasks.

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