zig_build · Zig MCP: Risk & Policy

WHAT IT DOES

What zig_build does on Zig

AI agents invoke zig_build to trigger actions in Zig. 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 zig_build needs a policy

This tool executes Zig build commands, which can compile code, run arbitrary build scripts, invoke external processes, and potentially modify the filesystem. The effects depend entirely on what the build configuration specifies, making it an Execute category risk rather than Write (which is reversible).

From the tool's definition Tool name 'zig_build' with description 'Run' indicates execution of a build process. The server description confirms it exposes a 'building' tool among language intelligence features.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

zig_build Rate-limited

zig_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": {
    "zig_build": {
      "limits": [
        {
          "counter": "zig_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 Zig, so you can run agents against it safely.

FAQ

Questions about zig_build

What does the zig_build tool do? +

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

How do I enforce a policy on zig_build? +

Register the Zig MCP server in PolicyLayer and add a rule for zig_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 Zig. Nothing to install.

What risk level is zig_build? +

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

Can I rate-limit zig_build? +

Yes. Add a rate_limit block to the zig_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 zig_build completely? +

Set action: deny in the PolicyLayer policy for zig_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 zig_build? +

zig_build is provided by the Zig MCP server (sadopc/mcp-server-zig). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.