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

Annotations already declare destructiveHint=true and openWorldHint=true, so the safety profile is partly covered; the description adds genuinely new context by documenting a validate_only dry-run and clarifying that Google Search is never disabled by this call. It still does not explain what 'destructive' means here (immediate live traffic loss, reversibility).

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?

Six short lines, the action front-loaded, then the operational rationale, then the parameter notes. Every sentence adds information and nothing is padded.

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 5-parameter destructive mutation with an output schema, the description covers side effects, dry-run capability, and optional-parameter defaults — enough to call it safely. Gaps remain around campaign-type prerequisites and what the response confirms.

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 0%, so the description must carry all parameter meaning. It does explain target_content_network (None = unchanged), validate_only (dry run), and workspace (optional with a single workspace), but leaves the required target_search_network and campaign_id undefined — and the relationship between target_search_network and 'real Google Search stays active' is only implied.

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 first line names a specific verb and resource: toggling the Search Partner / Display network of a campaign. It is clear what changes, but among the many ads_update_* siblings (notably ads_update_campaign_settings) it never states which one owns this setting, so the agent must infer the split.

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 gives useful context that this is the primary lever against search-partner traffic (hsa_src=s) and that real Google Search stays active, which implies when to reach for it. However, it never says when to use this versus ads_update_campaign_settings, nor whether prerequisites (campaign type, e.g. not PMax) apply.

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