Apply Patch Tool

Applies a unified diff (output of git diff) to local files. Mutation permission — gateway prompts for approval before execution.

Usage

# Inside an agent conversation:
"Here's the diff to apply:
```diff
--- a/src/server.ts
+++ b/src/server.ts
@@ -10,7 +10,7 @@
 export const PORT = 3000;
-export const HOST = '0.0.0.0';
+export const HOST = '127.0.0.1';
 ...
```

Apply with apply_patch and dry_run first."

Parameters

• patch (string, required) — unified diff content
• workdir (string) — working dir, default process.cwd()
• dry_run (boolean) — preview only, don't write. Default false.

Output

{
  "success": true,
  "data": {
    "dryRun": false,
    "filesAffected": 1,
    "applied": 1,
    "wouldApply": 0,
    "conflicts": 0,
    "results": [
      { "file": "src/server.ts", "status": "APPLIED", "hunks": 1 }
    ]
  }
}

Conflict handling

If a context line doesn't match the current file content, the hunk is rejected with status: "CONFLICT". The file is not modified.

Approval flow

Marked permission: "mutation". By default the gateway prompts via Approvals before writing. Auto-allow rules can opt out per-agent.

Source

Implementation: packages/plugins/apply-patch/