Apply Patch

Not yet available. The Apply Patch server tool is not yet available.

When a model produces a unified diff in response to a code-editing request, Apply Patch takes that diff and applies it to the original code block server-side, returning the patched result as a new message. Your application never has to implement diff parsing or patching logic.

Enabling apply patch#

{
  "model": "anthropic/claude-opus-4.8",
  "messages": [
    {
      "role": "user",
      "content": "Refactor this function to use early returns:\n\n```python\ndef process(x):\n    if x > 0:\n        if x < 100:\n            return x * 2\n    return 0\n```"
    }
  ],
  "tools": [
    { "type": "opendunes.apply_patch" }
  ]
}

The model produces a unified diff. The gateway detects the diff, locates the original code block in the conversation, applies the patch, and appends the patched file content as a subsequent assistant message part.

What the model receives back#

After the patch is applied, the assistant message includes a code block with the patched result:

{
  "role": "assistant",
  "content": [
    { "type": "text", "text": "Here is the refactored version:" },
    { "type": "text", "text": "```python\ndef process(x):\n    if x <= 0 or x >= 100:\n        return 0\n    return x * 2\n```" }
  ]
}

The model can then reason about the patched code in subsequent turns.

Configuration#

When patching fails#

If the diff cannot be applied cleanly (mismatched context lines, the original block changed), the gateway returns the raw diff in the message and sets a patch_failed: true field on the response. When strict: true, the request returns a 400 error instead.

Billing#

Apply Patch has no per-invocation fee. You pay only the token cost of the conversation and the diff content.