Image Generation

Image Generation

The image_generate tool lets the agent create and edit images using your configured providers. Generated images are delivered automatically as media attachments in the agent’s reply.

The tool only appears when at least one image generation provider is available. If you don’t see image_generate in your agent’s tools, configure agents.defaults.imageGenerationModel or set up a provider API key.

Quick start

1. Set an API key for at least one provider (for example OPENAI_API_KEY or GEMINI_API_KEY).
2. Optionally set your preferred model:

{
  agents: {
    defaults: {
      imageGenerationModel: {
        primary: "openai/gpt-image-1",
      },
    },
  },
}

3. Ask the agent: “Generate an image of a friendly lobster mascot.”

The agent calls image_generate automatically. No tool allow-listing needed — it’s enabled by default when a provider is available.

Supported providers

Provider	Default model	Edit support	API key
OpenAI	gpt-image-1	Yes (up to 5 images)	OPENAI_API_KEY
Google	gemini-3.1-flash-image-preview	Yes	GEMINI_API_KEY or GOOGLE_API_KEY
fal	fal-ai/flux/dev	Yes	FAL_KEY
MiniMax	image-01	Yes (subject reference)	MINIMAX_API_KEY or MiniMax OAuth (minimax-portal)
ComfyUI	workflow	Yes (1 image, workflow-configured)	COMFY_API_KEY or COMFY_CLOUD_API_KEY for cloud
Vydra	grok-imagine	No	VYDRA_API_KEY

Use action: "list" to inspect available providers and models at runtime:

/tool image_generate action=list

Tool parameters

Parameter	Type	Description
prompt	string	Image generation prompt (required for action: "generate")
action	string	"generate" (default) or "list" to inspect providers
model	string	Provider/model override, e.g. openai/gpt-image-1
image	string	Single reference image path or URL for edit mode
images	string[]	Multiple reference images for edit mode (up to 5)
size	string	Size hint: 1024x1024, 1536x1024, 1024x1536, 1024x1792, 1792x1024
aspectRatio	string	Aspect ratio: 1:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9
resolution	string	Resolution hint: 1K, 2K, or 4K
count	number	Number of images to generate (1–4)
filename	string	Output filename hint

Not all providers support all parameters. When a fallback provider supports a nearby geometry option instead of the exact requested one, Velaclaw remaps to the closest supported size, aspect ratio, or resolution before submission. Truly unsupported overrides are still reported in the tool result.

Tool results report the applied settings. When Velaclaw remaps geometry during provider fallback, the returned size, aspectRatio, and resolution values reflect what was actually sent, and details.normalization captures the requested-to-applied translation.

Configuration

Model selection

{
  agents: {
    defaults: {
      imageGenerationModel: {
        primary: "openai/gpt-image-1",
        fallbacks: ["google/gemini-3.1-flash-image-preview", "fal/fal-ai/flux/dev"],
      },
    },
  },
}

Provider selection order

When generating an image, Velaclaw tries providers in this order:

1. model parameter from the tool call (if the agent specifies one)
2. imageGenerationModel.primary from config
3. imageGenerationModel.fallbacks in order
4. Auto-detection — uses auth-backed provider defaults only:
   • current default provider first
   • remaining registered image-generation providers in provider-id order

If a provider fails (auth error, rate limit, etc.), the next candidate is tried automatically. If all fail, the error includes details from each attempt.

Notes:

• Auto-detection is auth-aware. A provider default only enters the candidate list when Velaclaw can actually authenticate that provider.
• Auto-detection is enabled by default. Set agents.defaults.mediaGenerationAutoProviderFallback: false if you want image generation to use only the explicit model, primary, and fallbacks entries.
• Use action: "list" to inspect the currently registered providers, their default models, and auth env-var hints.

Image editing

OpenAI, Google, fal, MiniMax, and ComfyUI support editing reference images. Pass a reference image path or URL:

"Generate a watercolor version of this photo" + image: "/path/to/photo.jpg"

OpenAI and Google support up to 5 reference images via the images parameter. fal, MiniMax, and ComfyUI support 1.

MiniMax image generation is available through both bundled MiniMax auth paths:

• minimax/image-01 for API-key setups
• minimax-portal/image-01 for OAuth setups

Provider capabilities

Capability	OpenAI	Google	fal	MiniMax	ComfyUI	Vydra
Generate	Yes (up to 4)	Yes (up to 4)	Yes (up to 4)	Yes (up to 9)	Yes (workflow-defined outputs)	Yes (1)
Edit/reference	Yes (up to 5 images)	Yes (up to 5 images)	Yes (1 image)	Yes (1 image, subject ref)	Yes (1 image, workflow-configured)	No
Size control	Yes	Yes	Yes	No	No	No
Aspect ratio	No	Yes	Yes (generate only)	Yes	No	No
Resolution (1K/2K/4K)	No	Yes	Yes	No	No	No

Related

• Tools Overview — all available agent tools
• fal — fal image and video provider setup
• ComfyUI — local ComfyUI and Comfy Cloud workflow setup
• Google (Gemini) — Gemini image provider setup
• MiniMax — MiniMax image provider setup
• OpenAI — OpenAI Images provider setup
• Vydra — Vydra image, video, and speech setup
• Configuration Reference — imageGenerationModel config
• Models — model configuration and failover