<tool_description> Cancel a media buy campaign. This is a terminal state — cannot be reactivated. </tool_description> <when_to_use> When an advertiser wants to permanently stop a campaign. Cannot be undone. Use pause for temporary stops. </when_to_use> <combination_hints> cancel is terminal. For ...
Part of the Discovery server.
Free to start. No card required.
AI agents may call cancel to permanently remove or destroy resources in Discovery. Without a policy, an autonomous agent could delete critical data in a loop with no way to undo the damage. PolicyLayer blocks destructive tools by default and requires explicit human approval before enabling them.
Without a policy, an AI agent could call cancel in a loop, permanently destroying resources in Discovery. There is no undo for destructive operations. PolicyLayer blocks this tool by default and only allows it when a human explicitly approves the action.
Destructive tools permanently remove data. Block by default. Only enable with explicit approval workflows.
{
"version": "1",
"default": "deny",
"hide": [
"cancel"
]
}See the full Discovery policy for all 19 tools.
These attack patterns abuse exactly the kind of access cancel gives an agent. Each links to the full case and the policy that stops it:
Other destructive tools across the catalogue. The same approach applies to each: deny by default, or require human approval.
<tool_description> Cancel a media buy campaign. This is a terminal state — cannot be reactivated. </tool_description> <when_to_use> When an advertiser wants to permanently stop a campaign. Cannot be undone. Use pause for temporary stops. </when_to_use> <combination_hints> cancel is terminal. For temporary suspension use pause instead. Remaining budget is released. </combination_hints> <output_format> Updated media buy with cancelled status. </output_format>. It is categorised as a Destructive tool in the Discovery MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Discovery MCP server in PolicyLayer and add a rule for cancel: 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 Discovery. Nothing to install.
cancel 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 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. 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 is provided by the Discovery MCP server (https://mcp.nexbid.dev/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 19 Discovery tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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