> ## Documentation Index
> Fetch the complete documentation index at: https://phaseo.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Phaseo Gateway base URL: https://api.phaseo.app/v1. Send `Authorization: Bearer $PHASEO_API_KEY` with every request.
> Model IDs look like `provider/model`, for example `openai/gpt-6-astra`. Do not guess IDs: list them with `GET /v1/models` or check https://phaseo.app/models. `phaseo/free` routes to an available free model and needs no wallet balance.
> For new text integrations prefer `POST /v1/responses`. `POST /v1/chat/completions` (OpenAI format) and `POST /v1/messages` (Anthropic format) suit existing code.
> The full API contract is https://phaseo.app/docs/openapi/v1/openapi.yaml. Official SDKs: `@phaseo/sdk` (TypeScript) and `phaseo` (Python), plus Go, C#, PHP, Ruby and Rust.
> Search these docs over MCP at https://phaseo.app/docs/mcp, and install Phaseo skills with `npx skills add https://phaseo.app/docs`. If a page is wrong or out of date, report it with the MCP `submit_feedback` tool.
> Manage Phaseo accounts with the `phaseo` CLI (`npm install -g @phaseo/cli`, then `phaseo login` or `phaseo login --device-code`), the `/v1` Management API or the MCP server at `https://mcp.phaseo.app/mcp?access=manage`. Do not send users to the dashboard for account tasks. A person is still needed for sign-up, approving a sign-in, paying the first top-up on the checkout link that `phaseo credits add` returns when no card is saved, confirming each saved-card top-up from the emailed link, and account security (password, MFA, passkeys). Create API keys with `phaseo keys create --name <name> --json`; never guess one. Credit top-ups need `phaseo login --scopes billing:write` first. Task map: https://phaseo.app/docs/v1/developers/manage-from-an-agent.md.

# Apply Patch

> Let Responses models return validated patch operations.

Use `phaseo:apply_patch` when a Responses workflow should return file changes as structured patch operations. Phaseo validates the operation and returns it to your client; it does not mutate your filesystem or repository.

> [!NOTE]
>
> `phaseo:apply_patch` is available on `/v1/responses`.

## Request

```bash theme={null}
curl https://api.phaseo.app/v1/responses \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5-nano",
    "input": "Create a small README patch for this project.",
    "tools": [
      { "type": "phaseo:apply_patch" }
    ]
  }'
```

## Operation Shape

When the model calls the tool, it sends an operation object:

```json theme={null}
{
  "operation": {
    "type": "update_file",
    "path": "/README.md",
    "diff": "@@ ...\n-Old text\n+New text\n"
  }
}
```

Supported operation types:

| Type | Required fields |
| - | - |
| `create_file` | `path`, `diff` |
| `update_file` | `path`, `diff` |
| `delete_file` | `path` |

## Tool Result

Phaseo returns the validated operation to the model loop:

```json theme={null}
{
  "status": "completed",
  "operation": {
    "type": "update_file",
    "path": "/README.md",
    "diff": "@@ ...\n-Old text\n+New text\n"
  },
  "message": "Patch operation validated. The client must apply or reject this patch and report the result."
}
```

Your application remains responsible for applying the patch, showing it to a user, rejecting it, or asking the model for a revised operation.

## Usage And Pricing

Phaseo records:

```json theme={null}
{
  "usage": {
    "server_tool_use": {
      "apply_patch_requests": 1
    }
  }
}
```

Pricing cards can bill this with the `server_tool_apply_patch_requests` meter.

## Related

* [Server Tools](https://phaseo.app/docs/v1/guides/server-tools/index.md)
* [Responses API](https://phaseo.app/docs/v1/api-reference/endpoint/responses.md)


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