AI agents call cancel_job to permanently remove resources in Workflows — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Cancelling a job is typically an irreversible action: a running or queued job that is cancelled cannot be 'uncancelled' and its in-progress work is lost. The name strongly implies terminating an active job permanently. In the context of a workflow automation server (where jobs may be executing real tasks), cancellation is at minimum Execute-level and likely Destructive due to irreversibility.
From the tool's definition Tool name 'cancel_job' — description is empty and uninformative.
Documented attack patterns abuse exactly the kind of access cancel_job gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Workflows, and nothing reaches the server without passing your rules. This is the rule we recommend for cancel_job:
{
"version": "1",
"default": "deny",
"hide": [
"cancel_job"
]
}cancel_job disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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cancel_job. It is categorised as a Destructive tool in the Workflows MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Workflows MCP server in PolicyLayer and add a rule for cancel_job: 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 Workflows. Nothing to install.
cancel_job is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the cancel_job 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 cancel_job. 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.
cancel_job is provided by the Workflows MCP server (qtsone/workflows-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Workflows, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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13 Workflows tools catalogued and risk-classified — across an index of 43,000+ MCP servers.