codemagic_start_build · Codemagic MCP: Risk & Policy

WHAT IT DOES

What codemagic_start_build does on Codemagic

AI agents invoke codemagic_start_build to trigger actions in Codemagic. 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 codemagic_start_build needs a policy

codemagic_start_build triggers real processes with real consequences. An agent gone sideways doesn't fire it once — it starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

codemagic_start_build Rate-limited

codemagic_start_build 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": {
    "codemagic_start_build": {
      "limits": [
        {
          "counter": "codemagic_start_build_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 Codemagic, so you can run agents against it safely.

FAQ

Questions about codemagic_start_build

What does the codemagic_start_build tool do? +

Trigger a new build for a workflow on a given branch or tag. Either branch or tag must be provided. Returns the new build identifier. It is categorised as a Execute tool in the Codemagic MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on codemagic_start_build? +

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

What risk level is codemagic_start_build? +

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

Can I rate-limit codemagic_start_build? +

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

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

codemagic_start_build is provided by the Codemagic MCP server (zfinix/codemagic_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.