Validate that IOC threat intelligence is fresh enough for the named action. Call this before any high-risk agent action to ensure the TI snapshot is not stale. The check itself completes in <1ms (no network I/O). Action → staleness tier mapping: critical (≤30s): credential_access, keychain_access...
Part of the Nullcone Threat Intelligence server.
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AI agents call check_freshness 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 check_freshness 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": {
"check_freshness": {}
}
}See the full Nullcone Threat Intelligence policy for all 30 tools.
These attack patterns abuse exactly the kind of access check_freshness 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.
Validate that IOC threat intelligence is fresh enough for the named action. Call this before any high-risk agent action to ensure the TI snapshot is not stale. The check itself completes in <1ms (no network I/O). Action → staleness tier mapping: critical (≤30s): credential_access, keychain_access, execute_shell, sudo high (≤120s): load_skill, install_package, network_call, http_request medium (≤300s): file_write, file_delete, registry_write, env_write low (≤900s): file_read, list_directory, query_db, read_env Args: action: The action about to be executed. Unknown actions default to HIGH tier (120s limit). block_on_stale: If True and TI is stale, return an error dict that your agent should treat as a hard block. Default False (warn only). Returns: action: "allow" | "warn" | "block" tier: Staleness tier for this action staleness_s: Seconds since last successful sync max_staleness_s: Limit for this tier hwm: Current high-water mark latency_ms: Check latency (always <100ms) reason: Human-readable explanation. 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 check_freshness: 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.
check_freshness 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 check_freshness 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 check_freshness. 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.
check_freshness 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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