worktree_merge · Lockstep MCP: Risk & Policy

WHAT IT DOES

What worktree_merge does on Lockstep

AI agents invoke worktree_merge to trigger actions in Lockstep. 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 worktree_merge needs a policy

Merging a worktree is an irreversible or hard-to-reverse git operation that modifies the repository's branch/commit history and working files. While not purely destructive (it doesn't delete), it executes an external operation with significant side effects.

From the tool's definition Tool name 'worktree_merge' and description 'Merge an implementer' — triggers a git worktree merge operation, which is an external VCS operation that can cause conflicts, overwrite changes, or alter repository state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

worktree_merge Rate-limited

worktree_merge 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": {
    "worktree_merge": {
      "limits": [
        {
          "counter": "worktree_merge_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 Lockstep, so you can run agents against it safely.

FAQ

Questions about worktree_merge

What does the worktree_merge tool do? +

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

How do I enforce a policy on worktree_merge? +

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

What risk level is worktree_merge? +

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

Can I rate-limit worktree_merge? +

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

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

worktree_merge is provided by the Lockstep MCP server (tmmoore286/lockstep-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.