acquire_build_slot · MCP Agent Mail MCP: Risk & Policy

WHAT IT DOES

What acquire_build_slot does on MCP Agent Mail

AI agents invoke acquire_build_slot to trigger actions in MCP Agent Mail. 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 acquire_build_slot needs a policy

The tool name indicates it acquires a build slot, which likely triggers or allocates computational resources for build execution. This is an Execute-category action (triggering external operations). However, confidence is moderate (0.6) because the description is empty, preventing full certainty.

From the tool's definition Tool name 'acquire_build_slot' suggests acquiring or reserving a build execution slot, implying some form of resource allocation or triggering of build processes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

acquire_build_slot Rate-limited

acquire_build_slot 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": {
    "acquire_build_slot": {
      "limits": [
        {
          "counter": "acquire_build_slot_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 MCP Agent Mail, so you can run agents against it safely.

FAQ

Questions about acquire_build_slot

What does the acquire_build_slot tool do? +

acquire_build_slot. It is categorised as a Execute tool in the MCP Agent Mail MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on acquire_build_slot? +

Register the MCP Agent Mail MCP server in PolicyLayer and add a rule for acquire_build_slot: 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 MCP Agent Mail. Nothing to install.

What risk level is acquire_build_slot? +

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

Can I rate-limit acquire_build_slot? +

Yes. Add a rate_limit block to the acquire_build_slot 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 acquire_build_slot completely? +

Set action: deny in the PolicyLayer policy for acquire_build_slot. 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 acquire_build_slot? +

acquire_build_slot is provided by the MCP Agent Mail MCP server (omelchmichael/mcp_agent_mail). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.