imgen-cli 0.1.6

Planner + CLI for managing durable image slots and variants

Image Slots Toolkit

This repository provides a complete workflow for managing durable image slots with generated variants. It includes:

• A remote FastMCP planner (server.py) that helps agents gather missing context and build CLI commands without touching local paths.
• A local CLI executor (imgen) that generates variants via the OpenRouter HTTP API (defaulting to Google Gemini 2.5 Flash Image Preview), writes session manifests, promotes variants atomically, and surfaces structured JSON for agents.
• A lightweight gallery server (imgen gallery serve) for browsing sessions and switching variants from the browser.

Getting started

1. Create a virtual environment and install dependencies from the lockfile:

   python -m venv .venv
   source .venv/bin/activate
   uv pip install -r requirements.txt
   

2. Install the package in editable mode if you want the imgen console script locally:

   uv pip install -e .
   

   (Once published to PyPI you can install globally via pipx install imgen-cli.)

3. Confirm the CLI is available:

imgen --help

Project setup

Initialize a project once to create .imagemcp/config.json and register the target asset directory:

imgen init \
  --project-root /path/to/your/project \
  --target-root public/img

After this step, all CLI commands auto-detect the project root (even when called from subdirectories) and write assets under the configured target folder.

CLI usage

Generate variants for a slot and receive structured JSON:

imgen gen \
  --slot hero \
  --target-root public/img \
  --prompt "Launch hero concept" \
  --n 3 \
  --json

• Variants are written under .imagemcp/.sessions/<slot>_<sessionId>/ with a manifest (session.json).
• The first variant is auto-promoted to <targetRoot>/<slot>.png using atomic writes.
• CLI output includes the selected index, target path, session directory, warnings, and a localhost gallery URL.

Switch to a different variant later:

imgen select \
  --target-root public/img \
  --slot hero \
  --session hero-20250101_abcdef \
  --index 2 \
  --json

Inspect slots and sessions:

imgen slots list --target-root public/img
imgen sessions list --target-root public/img --slot hero
imgen sessions info --target-root public/img --slot hero --session hero-20250101_abcdef

AI SDK bridge

The CLI calls OpenRouter directly over HTTPS and defaults to the google/gemini-2.5-flash-image-preview model. Configure OPENROUTER_API_KEY in .env before running imgen gen. Optional headers (like IMAGEMCP_OPENROUTER_HTTP_REFERER and IMAGEMCP_OPENROUTER_APP_TITLE) and concurrency (IMAGEMCP_OPENROUTER_MAX_WORKERS) can also be set via environment variables. If you prefer calling Google directly, set --provider google (or IMAGEMCP_DEFAULT_PROVIDER=google)—note that the pure-Python generator currently supports OpenRouter only.

Gallery server

Run the local gallery to browse variants from the browser:

imgen gallery serve --target-root public/img --port 8765 --open-browser

The gallery binds to localhost and allows selecting variants from any session. The CLI always prints the expected gallery URL so agents can surface it to users.

FastMCP planner

server.py exposes two planning tools for agents:

• collect_context_questions: identifies missing slot context, provides sensible defaults, and highlights provider constraints (size vs aspect ratio, seeds, etc.).
• plan_image_job: returns an AI generation plan along with a CLI command template and stdin payload ready for execution by the local CLI.

Run the planner locally during development:

python server.py

Testing

Install the test extras and run pytest:

uv pip install -e .[dev]
pytest

The tests cover end-to-end CLI behaviour (generation + selection) and planning logic.

Notes

• The default generator uses OpenRouter's HTTP API with the google/gemini-2.5-flash-image-preview model. Provide OPENROUTER_API_KEY in .env. To call Google directly, switch the --provider flag or set IMAGEMCP_DEFAULT_PROVIDER=google (direct Google support is not yet implemented in the pure-Python generator).
• You can still opt into the local mock generator for offline testing via --generator mock.
• All file operations enforce project-root scoping and use atomic promotion to keep dev servers stable.
• Update .env.example if new environment variables are introduced. Secrets must never be committed.