Check whether an IOC has been revoked. O(1) in-process lookup. Use this before acting on any cached threat intelligence to ensure the IOC has not been retracted since it was loaded. Args: value_hash: SHA256 of {ioc_type}:{value.lower()}. Returns: revoked: bool event: Revocation event details if r...
Part of the Nullcone Threat Intelligence server.
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AI agents call is_ioc_revoked to retrieve information from Nullcone Threat Intelligence without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though is_ioc_revoked only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"is_ioc_revoked": {}
}
}See the full Nullcone Threat Intelligence policy for all 30 tools.
These attack patterns abuse exactly the kind of access is_ioc_revoked gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Check whether an IOC has been revoked. O(1) in-process lookup. Use this before acting on any cached threat intelligence to ensure the IOC has not been retracted since it was loaded. Args: value_hash: SHA256 of {ioc_type}:{value.lower()}. Returns: revoked: bool event: Revocation event details if revoked, null otherwise.. It is categorised as a Read tool in the Nullcone Threat Intelligence MCP Server, which means it retrieves data without modifying state.
Register the Nullcone Threat Intelligence MCP server in PolicyLayer and add a rule for is_ioc_revoked: 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 Nullcone Threat Intelligence. Nothing to install.
is_ioc_revoked is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the is_ioc_revoked 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 is_ioc_revoked. 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.
is_ioc_revoked is provided by the Nullcone Threat Intelligence MCP server (https://nullcone.ai/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 30 Nullcone Threat Intelligence tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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