AI agents use assign_label_to_criterion 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 performs a reversible write operation on Google Ads resources by attaching labels to criteria. While the description is empty, the name and server context clearly indicate a metadata update action. This is classified as Write rather than Execute because it modifies data attributes rather than triggering campaigns or executing queries.
From the tool's definition Tool name 'assign_label_to_criterion' indicates modification of campaign/ad resource metadata. Server description mentions 'manage campaigns, budgets, keywords, conversions' via Google Ads API.
Documented attack patterns abuse exactly the kind of access assign_label_to_criterion 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 assign_label_to_criterion:
{
"version": "1",
"default": "deny",
"tools": {
"assign_label_to_criterion": {
"limits": [
{
"counter": "assign_label_to_criterion_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}assign_label_to_criterion 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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assign_label_to_criterion. 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 assign_label_to_criterion: 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.
assign_label_to_criterion 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 assign_label_to_criterion 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 assign_label_to_criterion. 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.
assign_label_to_criterion 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.