Gpt Imagegen

Bring ChatGPT Images 2.0 (gpt-image-2) to OpenCode. It uses your ChatGPT/Codex OAuth path first and can fall back to OmniRoute when Codex auth is unavailable.

Auth path	Status	Billing
ChatGPT subscription (Codex OAuth)	Default when available	Comes out of your existing Plus / Pro / Business plan
OmniRoute API	Fallback when Codex OAuth is absent	Depends on your OmniRoute backend/provider
OpenAI API key	Planned	Pay-per-image against your API credits, with generate + edit support

Highlights

• Subscription-friendly by default. Generations ride on the same Codex backend channel OpenCode already uses for ChatGPT subscription chat when Codex OAuth exists.
• OmniRoute fallback. If Codex OAuth is unavailable, the plugin can reuse OpenCode's omniroute API credential and OpenCode OmniRoute base URL config.
• Reference images. Pass input images alongside the prompt for style guidance, edit targets, or compositing inputs. Codex uses hosted input_image; OmniRoute sends data URLs through image_url / image_urls for compatible image models.

Installation

Add this plugin to your OpenCode config. For example, in opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["@makcimbx/opencode-gpt-imagegen"]
}

OpenCode auto-installs the package via Bun on next launch — no separate npm install step is needed. The plugin works best when OpenCode is authenticated with ChatGPT/Codex OAuth, and can also use OmniRoute credentials already stored in OpenCode auth.

Auth Selection

Default behavior is auto:

1. Use Codex OAuth from OpenCode's openai auth entry when available.
2. Otherwise fall back to OmniRoute API auth from OpenCode's omniroute auth entry or provider.omniroute.options.apiKey.

Force a provider for debugging:

GPT_IMAGEGEN_AUTH_PROVIDER=codex
GPT_IMAGEGEN_AUTH_PROVIDER=omniroute

OmniRoute configuration:

Variable / config	Purpose
`GPT_IMAGEGEN_AUTH_PROVIDER=auto	codex
GPT_IMAGEGEN_CODEX_MODEL	Overrides the Codex subscription model; default is gpt-5.6-sol
GPT_IMAGEGEN_OMNIROUTE_BASE_URL	Overrides the OmniRoute OpenAI-compatible base URL
GPT_IMAGEGEN_OMNIROUTE_MODEL	Overrides the OmniRoute image model; default is codex/gpt-5.6-sol
OpenCode omniroute auth	Preferred source for the OmniRoute API key
provider.omniroute.options.baseURL	Standard OpenCode provider base URL source
OmniRoute wrapper plugin options.baseURL	Supported fallback for wrapper configs such as ./plugins/omniroute-wrapper.ts

Base URLs are normalized so both https://host and https://host/v1 call POST /v1/images/generations without producing /v1/v1.

gpt-5.6-sol drives the hosted tool call; the rendered image still comes from gpt-image-2. If an account or OmniRoute deployment does not expose GPT-5.6 yet, use the corresponding model override to select gpt-5.5.

Exact size and quality are currently best-effort on Codex-backed paths. Codex OAuth forwards both values; OmniRoute forwards size but currently omits unverified quality. The upstream Codex image backend may still select automatic settings and return different PNG dimensions, and the plugin does not rescale the result. This affects both paths and is tracked in openai/codex#28723.

Usage

Just ask your agent in natural language and gpt_imagegen will be picked up.

The three examples below are the actual outputs of this repo's e2e test suite — see tests/e2e/subscription.test.ts for the exact prompts and assertions.

Example A — generate

Draw a man in a navy samue with a red hachimaki, standing in a garden full of cherry blossoms. 90s anime style. Save it as character.png, portrait 1024x1536.

Example B — auto-versioning

gpt_imagegen never overwrites an existing file: when the out path is already taken, it picks -v2, -v3, … instead.

Now do the same path but make it a woman in a yellow yukata holding a red wagasa, in a moonlit garden with fireflies. Landscape 1536x1024.

The previous character.png is left untouched; the new image lands at character-v2.png.

Example C — feed existing image files as input

Pass any number of image paths via the images argument and the model uses them as references for the next generation — for style guidance, characters to keep, scenes to extend, and so on.

Take character.png and character-v2.png and put both characters together on the engawa of an old Japanese house, smiling at the viewer. 2048x1152, same 90s anime style.

Roadmap

Version	Auth path	Scope	Status
v0.1.x	ChatGPT subscription + OmniRoute API	gpt_imagegen with provider selection, safe output, and optional reference images	Released
v0.2.0	OpenAI API key	Adds the API-key billing path: both generate (/v1/images/generations) and edit (/v1/images/edits) with reference images	Planned
Later	OpenAI API key	Adds pixel-precise mask inpainting via /v1/images/edits (binary PNG alpha mask)	Planned

How it works

OpenCode already talks to the OpenAI Codex backend to power ChatGPT subscription chat. This plugin reuses that same endpoint first, attaching the hosted image_generation tool to a single-turn request, then writes the returned PNG to disk.

When Codex OAuth is unavailable, the plugin can call OmniRoute's OpenAI-compatible POST /v1/images/generations endpoint. OmniRoute mode returns the same safe PNG output path and forwards reference images as data URLs for providers/models that accept image input.

Disclaimer

This is an unofficial, third-party plugin, not affiliated with or endorsed by OpenAI or OpenCode.

It uses the same Codex backend endpoint OpenCode itself calls for ChatGPT subscription chat — this plugin just adds the hosted image_generation tool to that conversation. Use must comply with OpenAI's Terms of Use and Usage Policies.