AI agents use mutate_custom_conversion_goals to create or update resources in Google Ads — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Google Ads environment.
This tool modifies conversion goals, which are critical configuration elements in Google Ads campaigns. Misuse could alter how campaign performance is tracked and reported, affecting budget allocation and business analytics. However, changes are reversible (can be updated again), so it is Write rather than Destructive.
From the tool's definition Tool name 'mutate_custom_conversion_goals' indicates modification of conversion goal data. The verb 'mutate' in Google Ads API terminology means create, update, or modify resources.
Documented attack patterns abuse exactly the kind of access mutate_custom_conversion_goals gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Google Ads, and nothing reaches the server without passing your rules. This is the rule we recommend for mutate_custom_conversion_goals:
{
"version": "1",
"default": "deny",
"tools": {
"mutate_custom_conversion_goals": {
"limits": [
{
"counter": "mutate_custom_conversion_goals_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}mutate_custom_conversion_goals stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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mutate_custom_conversion_goals. It is categorised as a Write tool in the Google Ads MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Google Ads MCP server in PolicyLayer and add a rule for mutate_custom_conversion_goals: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Google Ads. Nothing to install.
mutate_custom_conversion_goals is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the mutate_custom_conversion_goals rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for mutate_custom_conversion_goals. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
mutate_custom_conversion_goals is provided by the Google Ads MCP server (promobase/google-ads-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Google Ads, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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59 Google Ads tools catalogued and risk-classified — across an index of 43,000+ MCP servers.