Image Gen

Agent Plugins v1 Claude Code Plugin Codex Plugin Grok Build Plugin Skilz Marketplace License

Cover images and in-article illustrations for technical articles.

Hosts: Claude Code, Codex, Grok Build, Cursor, SKILZ / Agent Plugins 1.0.

Not the diagram renderer. Mermaid and PlantUML go to imagen-diagrams.

Image-engine hint and backend (auto)

To direct a generation through a specific host, pass one of:

--engine-hint imagen
--engine-hint grok
--engine-hint codex

imagen and grok-img are direct CLI adapters. codex is an agent adapter: the plugin asks Codex to save a PNG to the requested output path. grok-img renders into an isolated staging directory and the plugin normalizes its image to the requested path. A missing result fails closed and retains the prompt sidecar. With no hint, auto mode tries the available engines in order and continues after an authentication or runtime failure.

The official interactive Grok Build TUI supports /imagine <prompt>, but it saves a session image rather than accepting a requested output path. Use grok-img for the scriptable adapter:

npm install -g grok-image-cli
grok-img auth login

Backend order (auto)

imagen CLI if on PATH. Brace policy: imagen-cli-vars (double { }).
Then grok-img CLI. Brace policy: grok-imagine (no rewrite).
Else codex CLI. Brace policy: grok-imagine (no rewrite).
Else fail closed. Writes <stem>_imagen.prompt.txt and exits 2.

Nano Banana models

The install script upgrades gemini-imagen and pins Nano Banana 2 (gemini-3.1-flash-image). Cover generation uses Nano Banana Pro (gemini-3-pro-image).

Alias	Model ID	When
`nano-banana-2`	`gemini-3.1-flash-image`	Default article art
`nano-banana-pro`	`gemini-3-pro-image`	Covers, text-in-image
`nano-banana-2-lite`	`gemini-3.1-flash-lite-image`	Drafts
`nano-banana`	`gemini-2.5-flash-image`	Legacy fallback

Install

Claude Code / Grok Build

/plugin marketplace add SpillwaveSolutions/image_gen
/plugin install image-gen@spillwave-image-gen

Also listed in the skills catalog:

/plugin marketplace add SpillwaveSolutions/skills-marketplace
/plugin install image-gen@spillwave-skills

Codex

codex plugin marketplace add SpillwaveSolutions/image_gen

Grok Build

grok plugin install https://github.com/SpillwaveSolutions/image_gen --trust

Skilz

skilz install SpillwaveSolutions/image_gen

imagen CLI + models

python3 skills/image-gen/scripts/install_imagen.py
# needs GOOGLE_API_KEY or: imagen keys set google YOUR_KEY

Native plugin manifests

Host	Manifest	Marketplace
Claude Code	`.claude-plugin/plugin.json`	`.claude-plugin/marketplace.json`
Codex	`.codex-plugin/plugin.json`	`.agents/plugins/marketplace.json`
Grok Build	`.grok-plugin/plugin.json`	`.grok-plugin/marketplace.json`
Cursor	`.cursor-plugin/plugin.json`	`.cursor/rules/image-gen.mdc`
Universal	`plugin.json` (Agent Plugins v1)	Skilz

Quick start

mkdir -p work/images

python3 skills/image-gen/scripts/generate.py \
  --kind cover \
  --output work/images/article_cover.png \
  --prompt "A stunning digital art cover image showing three glowing pathways converging into a central AI cloud platform. Dramatic cinematic lighting. Style: conceptual, 3D render, high-detail, professional."

python3 skills/image-gen/scripts/generate.py \
  --kind article \
  --output work/images/article_diagram.png \
  --prompt "Technical diagram showing three color-coded client libraries connecting to a central platform with clear labels. Style: blueprint, clean."

Slash commands: /image-gen, /image-gen-install.

Commands

python3 tests/test_backend_detect.py
python3 tests/test_brace_policy.py
python3 tests/test_generate.py
python3 tests/test_models.py

License

MIT.