AI agents use update_custom_conversion_goal 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.
The tool updates (modifies) custom conversion goal settings, which is a reversible write operation with business impact. It affects how campaign performance is measured but does not delete data or execute arbitrary code. Severity is high because misconfigured conversion goals can skew reporting and decision-making for ad spend optimization.
From the tool's definition Tool name 'update_custom_conversion_goal' indicates modification of conversion tracking configuration. Server context shows it 'wraps the Google Ads API v20, enabling AI agents to manage campaigns, budgets, keywords, conversions' — update operations on…
Documented attack patterns abuse exactly the kind of access update_custom_conversion_goal 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 update_custom_conversion_goal:
{
"version": "1",
"default": "deny",
"tools": {
"update_custom_conversion_goal": {
"limits": [
{
"counter": "update_custom_conversion_goal_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_custom_conversion_goal 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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update_custom_conversion_goal. 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 update_custom_conversion_goal: 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.
update_custom_conversion_goal 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 update_custom_conversion_goal 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 update_custom_conversion_goal. 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.
update_custom_conversion_goal 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.