cairntir_crucible · Cairntir MCP: Risk & Policy

WHAT IT DOES

What cairntir_crucible does on Cairntir

AI agents invoke cairntir_crucible to trigger actions in Cairntir. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why cairntir_crucible needs a policy

The tool appears to execute a reasoning or evaluation process ('stress-test') against a provided claim. This is not a simple read or write, but rather an execution of an analytical skill. The description is vague, lowering confidence. It doesn't appear to be destructive, financial, or a plain read/write operation.

From the tool's definition 'Stress-test a claim with the Crucible skill' — implies running an analytical/evaluation process against a claim

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cairntir_crucible Rate-limited

cairntir_crucible stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "cairntir_crucible": {
      "limits": [
        {
          "counter": "cairntir_crucible_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Cairntir, so you can run agents against it safely.

FAQ

Questions about cairntir_crucible

What does the cairntir_crucible tool do? +

Stress-test a claim with the Crucible skill. It is categorised as a Execute tool in the Cairntir MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on cairntir_crucible? +

Register the Cairntir MCP server in PolicyLayer and add a rule for cairntir_crucible: 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 Cairntir. Nothing to install.

What risk level is cairntir_crucible? +

cairntir_crucible is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit cairntir_crucible? +

Yes. Add a rate_limit block to the cairntir_crucible 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.

How do I block cairntir_crucible completely? +

Set action: deny in the PolicyLayer policy for cairntir_crucible. 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.

What MCP server provides cairntir_crucible? +

cairntir_crucible is provided by the Cairntir MCP server (pnmcguire480/cairntir). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.