# Image Generation

nanobot can generate and edit images through the `generate_image` tool. Enable the tool in WebUI Settings, then ask for an image normally in chat; the agent decides when to call it and can keep iterating on generated images in the same conversation.

The feature is disabled by default. Open **Settings → Image**, choose a configured provider and model, enable image generation, save, and restart when prompted. If that screen is not available in your installed version, use the manual config below.

## Quick Setup

**WebUI**

1. Add the image provider credential under **Settings → Models** if it is not already configured.
2. Open **Settings → Image**.
3. Select the provider and image model, then enable image generation.
4. Save, restart when prompted, and ask for a simple test image.

**Manual config**

This snippet uses the current built-in image-generation default so the JSON has concrete names. It is not a provider recommendation; replace `provider` and `model` with any supported image provider and model you intend to use.

```json
{
  "providers": {
    "openrouter": {
      "apiKey": "${OPENROUTER_API_KEY}"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "openrouter",
      "model": "openai/gpt-5.4-image-2"
    }
  }
}
```

See [Provider Notes](#provider-notes) for Custom, AIHubMix, MiniMax, Gemini, Ollama, StepFun, and Zhipu configuration examples.

> [!TIP]
> Prefer environment variables for API keys. nanobot resolves `${VAR_NAME}` values from the environment at startup.

## WebUI Usage

1. Open Settings and enable **Image Generation** with a configured provider and model.
2. Describe the image or edit you want in chat.
3. Include an aspect ratio or size in the request when the configured defaults are not suitable.
4. Attach reference images when editing an existing image.

Generated images are rendered as assistant media in the chat. Follow-up prompts such as "make it warmer", "change the background", or "try a 16:9 version" can reuse the most recent generated artifact.

The WebUI hides provider storage details from the user. The agent sees the saved artifact path internally and can pass it back to `generate_image` as `reference_images` for iterative edits.

## Configuration Reference

| Option | Type | Default | Description |
|--------|------|---------|-------------|
| `tools.imageGeneration.enabled` | boolean | `false` | Register the `generate_image` tool |
| `tools.imageGeneration.provider` | string | `"openrouter"` | Current built-in image provider default. Supported values: `openrouter`, `openai`, `openai_codex`, `custom`, `aihubmix`, `minimax`, `gemini`, `ollama`, `stepfun`, `zhipu` |
| `tools.imageGeneration.model` | string | `"openai/gpt-5.4-image-2"` | Provider model name |
| `tools.imageGeneration.defaultAspectRatio` | string | `"1:1"` | Default ratio when the prompt/tool call does not specify one |
| `tools.imageGeneration.defaultImageSize` | string | `"1K"` | Default size hint, for example `1K`, `2K`, `4K`, or `1024x1024` |
| `tools.imageGeneration.maxImagesPerTurn` | number | `4` | Maximum `count` accepted by one tool call. Valid range: `1` to `8` |
| `tools.imageGeneration.saveDir` | string | `"generated"` | Relative directory under nanobot's media directory for generated artifacts |

Provider settings reuse normal provider config fields:

| Option | Description |
|--------|-------------|
| `providers.<name>.apiKey` | Provider API key. Prefer `${ENV_VAR}` |
| `providers.<name>.apiBase` | Optional custom base URL |
| `providers.<name>.extraHeaders` | Headers merged into provider requests |
| `providers.<name>.extraBody` | Extra JSON fields merged into provider request bodies |

Both camelCase and snake_case config keys are accepted, but docs use camelCase to match `config.json`.

## Provider Notes

### OpenRouter

OpenRouter uses a chat-completions style image response. Configure:

```json
{
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "openrouter",
      "model": "openai/gpt-5.4-image-2"
    }
  }
}
```

Use a model that supports image generation and image editing if you want reference-image edits.

### Custom (OpenAI-compatible)

The `custom` image provider fits services that implement the synchronous OpenAI Images API:

```text
POST /v1/images/generations
```

The response must include generated images in `data[].b64_json` or `data[].url`. Native prediction APIs, such as Replicate's `/v1/models/{owner}/{model}/predictions`, are not directly compatible unless you put an OpenAI-compatible gateway in front of them.

Configure:

```json
{
  "providers": {
    "custom": {
      "apiKey": "${CUSTOM_IMAGE_API_KEY}",
      "apiBase": "https://api.example.com/v1"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "custom",
      "model": "your-model-name"
    }
  }
}
```

The `apiBase` is required. The provider sends requests to `{apiBase}/images/generations` using the OpenAI Images API format with `response_format: "b64_json"`. The `apiKey` is optional for local or unauthenticated endpoints. Reference-image edits are not supported by the generic `custom` provider.

`extraBody` can adapt provider-specific quirks because it is merged last into the request body. Examples:

- Agnes AI documents URL responses, so use `"extraBody": {"response_format": "url"}`.
- Together AI documents `"response_format": "base64"`, so override the default.
- Volcengine Ark Seedream models may require size hints such as `"2K"`, `"3K"`, `"4K"`, or explicit dimensions. Set `tools.imageGeneration.defaultImageSize` or `providers.custom.extraBody.size` to a value supported by the selected model.

For compatibility with the default nanobot setting, custom maps `defaultImageSize: "1K"` to `1024x1024`. Other explicit size hints are passed through unchanged.

### AIHubMix

AIHubMix `gpt-image-2-free` is supported through AIHubMix's unified predictions API. Internally nanobot calls:

```text
/v1/models/openai/gpt-image-2-free/predictions
```

Configure:

```json
{
  "providers": {
    "aihubmix": {
      "apiKey": "${AIHUBMIX_API_KEY}",
      "extraBody": {
        "quality": "low"
      }
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "aihubmix",
      "model": "gpt-image-2-free"
    }
  }
}
```

`quality: low` is optional. It can make free image models faster and less likely to time out, but it is not required for correctness.

### MiniMax

MiniMax `image-01` supports text-to-image and reference-image (subject reference) edits. Supported aspect ratios are `1:1`, `16:9`, `4:3`, `3:2`, `2:3`, `3:4`, `9:16`, and `21:9`.

```json
{
  "providers": {
    "minimax": {
      "apiKey": "${MINIMAX_API_KEY}"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "minimax",
      "model": "image-01",
      "defaultAspectRatio": "1:1"
    }
  }
}
```

### Gemini

nanobot supports two Gemini image generation model families via Google's Generative Language API:

| Model | Endpoint | Reference images |
|-------|----------|-----------------|
| `imagen-4.0-generate-001` | `:predict` | Not supported by this integration |
| `gemini-2.5-flash-image` | `:generateContent` | Supported |

For reference-image edits, use a Gemini Flash image model:

```json
{
  "providers": {
    "gemini": {
      "apiKey": "${GEMINI_API_KEY}"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "gemini",
      "model": "gemini-2.5-flash-image"
    }
  }
}
```

Imagen 4 supports the aspect ratios `1:1`, `9:16`, `16:9`, `3:4`, and `4:3`. Unsupported ratios are ignored and the model uses its default. The `defaultImageSize` setting has no effect on Gemini models; sizing is controlled by `defaultAspectRatio` only. Reference images passed with an Imagen model are ignored (with a warning logged).

### Ollama

Ollama's experimental native image generation API works with local servers and hosted ollama.com models. Local access at `http://localhost:11434/api` does not require an API key; set `providers.ollama.apiKey` only when targeting `https://ollama.com/api`.

```json
{
  "providers": {
    "ollama": {
      "apiBase": "http://localhost:11434/api"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "ollama",
      "model": "x/z-image-turbo",
      "defaultAspectRatio": "16:9",
      "defaultImageSize": "2K"
    }
  }
}
```

Ollama maps `defaultAspectRatio` and `defaultImageSize` to native `width` and `height` values. Reference images are not supported by this integration.

### StepFun

StepFun (阶跃星辰) `step-image-edit-2` supports text-to-image generation.  The `step-1x-medium` variant additionally supports **style-reference** image edits, where a reference image guides the visual style of the output.

Supported aspect ratios: `1:1`, `16:9`, `9:16`, `3:4`, `4:3`.  Sizes are specified as `WIDTHxHEIGHT` (e.g. `1024x1024`, `1280x800`, `800x1280`).

```json
{
  "providers": {
    "stepfun": {
      "apiKey": "${STEPFUN_API_KEY}"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "stepfun",
      "model": "step-image-edit-2"
    }
  }
}
```

> [!NOTE]
> The StepFun provider reuses the existing `providers.stepfun` config block (the same one used for StepFun's LLM API).  Set `providers.stepfun.apiKey` once and it is shared between text and image generation.
>
> When `step-image-edit-2` is used, `reference_images` are ignored (the model does not support style reference).  Switch to `step-1x-medium` to use reference-image-guided generation.

#### StepPlan (Subscription)

StepPlan is StepFun's subscription tier and uses a different API base URL. The image generation endpoint path is the same — just override `apiBase`:

```json
{
  "providers": {
    "stepfun": {
      "apiKey": "${STEPFUN_API_KEY}",
      "apiBase": "https://api.stepfun.ai/step_plan/v1"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "stepfun",
      "model": "step-image-edit-2"
    }
  }
}
```

`apiBase` takes precedence over the registry default, so with the StepPlan base URL configured, image requests are sent to `https://api.stepfun.ai/step_plan/v1/images/generations` — the same path prefix used for LLM calls. The API key is shared with the standard StepFun provider.

### Zhipu

Zhipu (智谱) `glm-image` model supports text-to-image generation. The API returns temporary image URLs (valid for 30 days); nanobot downloads and re-encodes them as base64 data URLs.

Supported aspect ratios: `1:1`, `16:9`, `9:16`, `3:4`, `4:3`. Sizes can be specified as `WIDTHxHEIGHT` (e.g. `1280x1280`, `1728x960`) or using aspect ratio presets.

```json
{
  "providers": {
    "zhipu": {
      "apiKey": "${ZAI_API_KEY}"
    }
  },
  "tools": {
    "imageGeneration": {
      "enabled": true,
      "provider": "zhipu",
      "model": "glm-image"
    }
  }
}
```

Other supported models: `cogview-4`, `cogview-4-250304`, `cogview-3-flash`. Reference images are not supported by this integration.

## Artifacts

Generated images are stored under the active nanobot instance's media directory:

```text
~/.nanobot/media/generated/YYYY-MM-DD/img_<id>.<ext>
~/.nanobot/media/generated/YYYY-MM-DD/img_<id>.json
```

For non-default config locations, the media directory is relative to the active config file's directory.

The JSON sidecar stores:

| Field | Meaning |
|-------|---------|
| `id` | Short generated image id, such as `img_ab12cd34ef56` |
| `path` | Local image path used internally for follow-up edits |
| `mime` | Detected image MIME type |
| `prompt` | Prompt used for the generation |
| `model` | Provider model |
| `provider` | Provider name |
| `source_images` | Reference image paths used for edits |
| `created_at` | Creation timestamp |

Do not paste base64 image payloads into chat. The agent should keep local artifact paths internal unless the user explicitly asks for debugging details.

## Prompting

Good image prompts include:

- Subject and scene.
- Composition, camera, or layout.
- Style, mood, lighting, and color palette.
- Exact text that must appear in the image, quoted.
- Constraints such as "keep the same character" or "preserve the logo".

Example:

```text
A minimal app icon for nanobot: friendly robot head, rounded square, soft blue and white palette, clean vector style, no text
```

For edits, describe what should change and what must stay fixed:

```text
Use the reference image. Keep the same robot and composition, change the palette to warm orange, and add a subtle sunrise background.
```

## Troubleshooting

| Symptom | Check |
|---------|-------|
| `generate_image` is not available | Set `tools.imageGeneration.enabled` to `true` and restart the gateway |
| Missing API key error | Configure `providers.<provider>.apiKey`; if using `${VAR_NAME}`, confirm the environment variable is visible to the gateway process |
| `unsupported image generation provider` | Use `openrouter`, `openai`, `openai_codex`, `custom`, `aihubmix`, `minimax`, `gemini`, `ollama`, `stepfun`, or `zhipu` |
| AIHubMix says `Incorrect model ID` | Use `model: "gpt-image-2-free"`; nanobot expands it to the required `openai/gpt-image-2-free` model path internally |
| Generation times out | Try a smaller/default image size, set AIHubMix `extraBody.quality` to `"low"`, or retry later |
| Reference image rejected | Reference image paths must be inside the workspace or nanobot media directory and must be valid image files |
