yaml__parse · Code Mode Bridge MCP: Risk & Policy

WHAT IT DOES

What yaml__parse does on Code Mode Bridge

AI agents invoke yaml__parse to trigger actions in Code Mode Bridge. 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 yaml__parse needs a policy

While YAML parsing itself is a Read/transform operation, this tool exists within a code execution sandbox bridge where inputs may be evaluated as JavaScript values. The broader execution context elevates the risk, as parsed YAML values could feed into downstream code execution. However, if taken in isolation, pure YAML parsing is low-risk; the sandbox context warrants medium severity and Execute classification.

From the tool's definition The server description states it 'enables agents to run generated code in an isolated sandbox' and aggregates tools for 'unified orchestration and execution'.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

yaml__parse Rate-limited

yaml__parse 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": {
    "yaml__parse": {
      "limits": [
        {
          "counter": "yaml__parse_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 Code Mode Bridge, so you can run agents against it safely.

FAQ

Questions about yaml__parse

What does the yaml__parse tool do? +

Parse a YAML string into a JavaScript value. It is categorised as a Execute tool in the Code Mode Bridge MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on yaml__parse? +

Register the Code Mode Bridge MCP server in PolicyLayer and add a rule for yaml__parse: 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 Code Mode Bridge. Nothing to install.

What risk level is yaml__parse? +

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

Can I rate-limit yaml__parse? +

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

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

yaml__parse is provided by the Code Mode Bridge MCP server (ruifung/mcp-cm-bridge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.