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| Author | SHA1 | Date | |
|---|---|---|---|
| 7a21b02081 | |||
| 1340d3098f | |||
| 8cbeb6571b | |||
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+39
-3
@@ -8,7 +8,13 @@
|
||||
"/home/pplate/pi_mcps/"
|
||||
],
|
||||
"alwaysAllow": [
|
||||
"*"
|
||||
"git_status",
|
||||
"git_diff_unstaged",
|
||||
"git_log",
|
||||
"git_add",
|
||||
"git_commit",
|
||||
"git_branch",
|
||||
"git_create_branch"
|
||||
]
|
||||
},
|
||||
"filesystem": {
|
||||
@@ -27,7 +33,9 @@
|
||||
"/home/pplate/pi_mcps/mcp/webscraper",
|
||||
"src/server.py"
|
||||
],
|
||||
"alwaysAllow": []
|
||||
"alwaysAllow": [
|
||||
"webscraper_fetch"
|
||||
]
|
||||
},
|
||||
"gitea": {
|
||||
"command": "/home/pplate/.local/bin/forgejo-mcp",
|
||||
@@ -39,14 +47,42 @@
|
||||
"8bf0c734ebda3e61d9c9068489ce58a2bf8d33db"
|
||||
],
|
||||
"alwaysAllow": [
|
||||
"*"
|
||||
"create_issue",
|
||||
"list_repo_issues",
|
||||
"get_issue",
|
||||
"edit_issue",
|
||||
"create_issue_comment",
|
||||
"create_pull_request",
|
||||
"get_repository",
|
||||
"list_my_repositories"
|
||||
]
|
||||
},
|
||||
"playwright": {
|
||||
"command": "npx",
|
||||
"args": [
|
||||
"@playwright/mcp@latest"
|
||||
],
|
||||
"alwaysAllow": [
|
||||
"browser_navigate",
|
||||
"browser_click",
|
||||
"browser_fill",
|
||||
"browser_screenshot",
|
||||
"browser_close",
|
||||
"browser_new_context"
|
||||
]
|
||||
},
|
||||
"mcp-image-gen": {
|
||||
"command": "uv",
|
||||
"args": [
|
||||
"--directory",
|
||||
"/home/pplate/pi_mcps/mcp/mcp-image-gen",
|
||||
"run",
|
||||
"src/server.py"
|
||||
],
|
||||
"env": {
|
||||
"COMFYUI_URL": "http://localhost:8188",
|
||||
"IMAGE_OUTPUT_DIR": "/home/pplate/Pictures/mcp-generated"
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,588 @@
|
||||
# mcp-image-gen — Usage Guide
|
||||
|
||||
> **Comprehensive reference for using the ComfyUI-backed image generation MCP server**
|
||||
|
||||
---
|
||||
|
||||
## Table of Contents
|
||||
|
||||
1. [Prerequisites — ComfyUI Setup](#1-prerequisites--comfyui-setup)
|
||||
2. [Quick Start — Running the MCP Server](#2-quick-start--running-the-mcp-server)
|
||||
3. [How to Ask Lumen to Generate Images](#3-how-to-ask-lumen-to-generate-images)
|
||||
4. [Available Tools](#4-available-tools)
|
||||
5. [Parameters Reference](#5-parameters-reference)
|
||||
6. [Output Format](#6-output-format)
|
||||
7. [Environment Variables](#7-environment-variables)
|
||||
8. [Test Status](#8-test-status)
|
||||
9. [Prompt Tips for FLUX.1-schnell](#9-prompt-tips-for-flux1-schnell)
|
||||
10. [Known Limitations](#10-known-limitations)
|
||||
|
||||
---
|
||||
|
||||
## 1. Prerequisites — ComfyUI Setup
|
||||
|
||||
### ComfyUI must be running before any image generation tool call succeeds.
|
||||
|
||||
The MCP server connects to ComfyUI's REST API at `http://localhost:8188`. If ComfyUI is not running, `generate_image` and `list_available_models` will return a graceful error message — no crash.
|
||||
|
||||
### Install ComfyUI
|
||||
|
||||
```bash
|
||||
# Option A — pip install (simplest)
|
||||
pip install comfyui
|
||||
|
||||
# Option B — git clone (more control)
|
||||
git clone https://github.com/comfyanonymous/ComfyUI.git
|
||||
cd ComfyUI
|
||||
pip install -r requirements.txt
|
||||
```
|
||||
|
||||
### Install PyTorch with ROCm (AMD RX 7900 XTX)
|
||||
|
||||
Patrick's RX 7900 XTX (gfx1100, 24GB VRAM) uses the ROCm backend. Standard CUDA builds **will not work** on AMD hardware.
|
||||
|
||||
```bash
|
||||
# PyTorch with ROCm 6.1 support
|
||||
pip install torch torchvision --index-url https://download.pytorch.org/whl/rocm6.1
|
||||
```
|
||||
|
||||
> **ROCm version note:** ROCm 7.2.1 is the current production release as of April 2026.
|
||||
> Check `rocm-smi` to confirm your ROCm version before installing torch.
|
||||
|
||||
### Download FLUX.1-schnell (Primary Model)
|
||||
|
||||
FLUX.1-schnell is the recommended model — fast (4 steps), Apache 2.0 licensed, excellent quality.
|
||||
|
||||
```bash
|
||||
# Download (~8GB) — place in ComfyUI/models/checkpoints/
|
||||
wget https://huggingface.co/black-forest-labs/FLUX.1-schnell/resolve/main/flux1-schnell.safetensors \
|
||||
-O ~/ComfyUI/models/checkpoints/flux1-schnell.safetensors
|
||||
|
||||
# Or use huggingface_hub:
|
||||
huggingface-cli download black-forest-labs/FLUX.1-schnell \
|
||||
flux1-schnell.safetensors \
|
||||
--local-dir ~/ComfyUI/models/checkpoints/
|
||||
```
|
||||
|
||||
You'll also need the CLIP and VAE models — see the [ComfyUI FLUX guide](https://github.com/comfyanonymous/ComfyUI/blob/master/README.md) for full model list.
|
||||
|
||||
### Start ComfyUI (AMD ROCm)
|
||||
|
||||
```bash
|
||||
# Standard start — listens on all interfaces at port 8188
|
||||
HSA_OVERRIDE_GFX_VERSION=11.0.0 python main.py --listen
|
||||
|
||||
# Or with explicit port
|
||||
HSA_OVERRIDE_GFX_VERSION=11.0.0 python main.py --listen --port 8188
|
||||
```
|
||||
|
||||
> **`HSA_OVERRIDE_GFX_VERSION=11.0.0`** — Required for RX 7900 XTX (gfx1100).
|
||||
> Without this, ROCm may fail to detect the GPU correctly. This tells the HIP runtime
|
||||
> to treat the GPU as gfx1100 architecture.
|
||||
|
||||
### Verify ComfyUI is Running
|
||||
|
||||
```bash
|
||||
curl -s http://localhost:8188/system_stats | python3 -m json.tool | head -20
|
||||
```
|
||||
|
||||
Expected response includes `system` object with `python_version`, `pytorch_version`, `embedded_python`, and `comfyui_version`.
|
||||
|
||||
---
|
||||
|
||||
## 2. Quick Start — Running the MCP Server
|
||||
|
||||
### Via `run.sh` (recommended)
|
||||
|
||||
```bash
|
||||
cd /home/pplate/pi_mcps/mcp/mcp-image-gen
|
||||
./run.sh
|
||||
```
|
||||
|
||||
[`run.sh`](run.sh) automatically:
|
||||
- Sets `PATH` to include `~/.local/bin` for `uv`
|
||||
- Creates `IMAGE_OUTPUT_DIR` (`~/Pictures/mcp-generated`) if it doesn't exist
|
||||
- Launches the FastMCP server via `uv run src/server.py` (stdio transport)
|
||||
|
||||
### Via uv directly
|
||||
|
||||
```bash
|
||||
cd /home/pplate/pi_mcps/mcp/mcp-image-gen
|
||||
uv run src/server.py
|
||||
```
|
||||
|
||||
### Wired into `.roo/mcp.json`
|
||||
|
||||
The server is already configured in [`.roo/mcp.json`](../../.roo/mcp.json):
|
||||
|
||||
```json
|
||||
"mcp-image-gen": {
|
||||
"command": "uv",
|
||||
"args": [
|
||||
"--directory", "/home/pplate/pi_mcps/mcp/mcp-image-gen",
|
||||
"run", "src/server.py"
|
||||
],
|
||||
"env": {
|
||||
"COMFYUI_URL": "http://localhost:8188",
|
||||
"IMAGE_OUTPUT_DIR": "/home/pplate/Pictures/mcp-generated"
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Roo Code / Claude Desktop will auto-start the server when any image generation tool is invoked. The MCP server itself starts in ~1 second — ComfyUI must already be running separately.
|
||||
|
||||
### Install dependencies (first time)
|
||||
|
||||
```bash
|
||||
cd /home/pplate/pi_mcps/mcp/mcp-image-gen
|
||||
uv sync
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 3. How to Ask Lumen to Generate Images
|
||||
|
||||
Just speak naturally. Lumen will call the appropriate MCP tool automatically.
|
||||
|
||||
### Basic generation
|
||||
|
||||
> *"Generate an image of a futuristic city at sunset"*
|
||||
|
||||
```
|
||||
→ generate_image(prompt="futuristic city at sunset", width=1024, height=1024, steps=4)
|
||||
```
|
||||
|
||||
### Specific style and size
|
||||
|
||||
> *"Create a portrait of a red fox in watercolor style, 1024x1024"*
|
||||
|
||||
```
|
||||
→ generate_image(
|
||||
prompt="portrait of a red fox, watercolor style, detailed fur, soft brushstrokes",
|
||||
width=1024, height=1024
|
||||
)
|
||||
```
|
||||
|
||||
### Reproducible with a fixed seed
|
||||
|
||||
> *"Make an image with seed 42 so I can reproduce it"*
|
||||
|
||||
```
|
||||
→ generate_image(prompt="...", seed=42)
|
||||
```
|
||||
|
||||
The seed is reported in the text output so you can use the same seed again.
|
||||
|
||||
### Landscape format
|
||||
|
||||
> *"Generate a wide cinematic landscape of a Norwegian fjord, 1920x1080"*
|
||||
|
||||
```
|
||||
→ generate_image(prompt="Norwegian fjord, cinematic, golden hour", width=1920, height=1080)
|
||||
```
|
||||
|
||||
### Excluding unwanted elements
|
||||
|
||||
> *"Generate a clean product photo of a coffee mug, no background clutter, no text"*
|
||||
|
||||
```
|
||||
→ generate_image(
|
||||
prompt="product photo of a ceramic coffee mug, studio lighting, white background",
|
||||
negative_prompt="clutter, text, watermark, blurry, shadows"
|
||||
)
|
||||
```
|
||||
|
||||
### More inference steps for higher quality
|
||||
|
||||
> *"Generate a highly detailed oil painting of a medieval castle, use 20 steps"*
|
||||
|
||||
```
|
||||
→ generate_image(
|
||||
prompt="oil painting of a medieval castle, highly detailed, dramatic lighting",
|
||||
steps=20,
|
||||
model="flux1-dev.safetensors" # FLUX.1-dev supports higher step counts better
|
||||
)
|
||||
```
|
||||
|
||||
### Check what models are available
|
||||
|
||||
> *"List what models are available in ComfyUI"*
|
||||
|
||||
```
|
||||
→ list_available_models()
|
||||
```
|
||||
|
||||
### Check status of a long-running job
|
||||
|
||||
> *"What's the status of prompt ID abc-123?"*
|
||||
|
||||
```
|
||||
→ get_generation_status(prompt_id="abc-123")
|
||||
```
|
||||
|
||||
### Find out where images are saved
|
||||
|
||||
> *"Where are my generated images being saved?"*
|
||||
|
||||
```
|
||||
→ get_output_directory()
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 4. Available Tools
|
||||
|
||||
### `generate_image`
|
||||
|
||||
Generate an image from a text prompt using ComfyUI's FLUX.1-schnell workflow.
|
||||
|
||||
**Full signature:**
|
||||
```python
|
||||
async def generate_image(
|
||||
prompt: str,
|
||||
width: int = 1024,
|
||||
height: int = 1024,
|
||||
steps: int = 4,
|
||||
model: str = "flux1-schnell.safetensors",
|
||||
seed: int = -1,
|
||||
negative_prompt: str = "",
|
||||
output_dir: str = "",
|
||||
) -> list[TextContent | ImageContent]
|
||||
```
|
||||
|
||||
**What it does:**
|
||||
1. Loads the bundled `flux_schnell.json` ComfyUI API workflow template
|
||||
2. Injects your prompt, dimensions, seed, model into the correct workflow nodes
|
||||
3. Submits the workflow to ComfyUI via `POST /api/prompt`
|
||||
4. Polls `/api/queue` every 2 seconds until the job leaves the queue
|
||||
5. Fetches history via `/api/history/{prompt_id}` to find the output filename
|
||||
6. Downloads the PNG from `/api/view`
|
||||
7. Saves the PNG to disk as `YYYYMMDD_HHMMSS_{seed}.png`
|
||||
8. Returns `[TextContent(path + metadata), ImageContent(base64 PNG)]`
|
||||
|
||||
---
|
||||
|
||||
### `list_available_models`
|
||||
|
||||
List all checkpoint models currently available in ComfyUI.
|
||||
|
||||
```python
|
||||
async def list_available_models() -> list[str]
|
||||
```
|
||||
|
||||
Calls `/object_info/CheckpointLoaderSimple` and extracts the checkpoint name list. Use this to discover what models are installed before passing a `model` name to `generate_image`.
|
||||
|
||||
**Example return:**
|
||||
```json
|
||||
["flux1-schnell.safetensors", "flux1-dev.safetensors", "sd_xl_base_1.0.safetensors"]
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### `get_generation_status`
|
||||
|
||||
Check the status of a queued or running generation job.
|
||||
|
||||
```python
|
||||
async def get_generation_status(prompt_id: str) -> dict
|
||||
```
|
||||
|
||||
**Return values:**
|
||||
|
||||
| `status` | Meaning |
|
||||
|---|---|
|
||||
| `"pending"` | Job is in the queue, not yet started |
|
||||
| `"running"` | Job is currently being processed |
|
||||
| `"completed"` | Job finished — image is in ComfyUI's history |
|
||||
| `"not_found"` | Unknown prompt_id — may have expired from history |
|
||||
| `"error"` | ComfyUI was unreachable |
|
||||
|
||||
Useful when `generate_image` times out (default 120s) — the job may still be running in ComfyUI.
|
||||
|
||||
---
|
||||
|
||||
### `get_output_directory`
|
||||
|
||||
Return the absolute path where generated images will be saved.
|
||||
|
||||
```python
|
||||
def get_output_directory() -> str
|
||||
```
|
||||
|
||||
Returns the expanded, absolute path derived from `IMAGE_OUTPUT_DIR` env var (or `~/Pictures/mcp-generated` default). The directory may not exist yet — `generate_image` creates it on first use.
|
||||
|
||||
---
|
||||
|
||||
## 5. Parameters Reference
|
||||
|
||||
Full parameter table for `generate_image`:
|
||||
|
||||
| Parameter | Type | Default | Description |
|
||||
|---|---|---|---|
|
||||
| `prompt` | `str` | *(required)* | Text description of the image. Goes into the positive CLIP text encoder node. |
|
||||
| `width` | `int` | `1024` | Image width in pixels. FLUX.1-schnell: 512–2048 recommended. |
|
||||
| `height` | `int` | `1024` | Image height in pixels. FLUX.1-schnell: 512–2048 recommended. |
|
||||
| `steps` | `int` | `4` | Number of KSampler inference steps. FLUX.1-schnell is designed for 1–8 steps. |
|
||||
| `model` | `str` | `"flux1-schnell.safetensors"` | Checkpoint model filename as listed by `list_available_models`. |
|
||||
| `seed` | `int` | `-1` | RNG seed for reproducibility. `-1` = new random seed each call (0 to 2³²−1). |
|
||||
| `negative_prompt` | `str` | `""` | Text description of things to exclude. Goes into negative CLIP encoder node. |
|
||||
| `output_dir` | `str` | `""` | Override save directory. Empty = uses `IMAGE_OUTPUT_DIR` env var or default. |
|
||||
|
||||
### Recommended dimensions
|
||||
|
||||
| Use case | Width | Height |
|
||||
|---|---|---|
|
||||
| Square (default) | 1024 | 1024 |
|
||||
| Portrait | 768 | 1024 |
|
||||
| Landscape | 1024 | 768 |
|
||||
| Widescreen | 1280 | 720 |
|
||||
| HD widescreen | 1920 | 1080 |
|
||||
| Tall portrait | 512 | 768 |
|
||||
|
||||
> **VRAM note:** Patrick's RX 7900 XTX has 24GB VRAM. FLUX.1-schnell requires ~8GB,
|
||||
> so you can comfortably run 1920×1080 and even larger. FLUX.1-dev requires ~12GB.
|
||||
|
||||
---
|
||||
|
||||
## 6. Output Format
|
||||
|
||||
`generate_image` returns a list with **two items** when successful:
|
||||
|
||||
### Item 1 — `TextContent` (file path + metadata)
|
||||
|
||||
```
|
||||
Generated: /home/pplate/Pictures/mcp-generated/20260404_121500_3847291045.png
|
||||
Seed: 3847291045
|
||||
Elapsed: 8.3s
|
||||
Size: 1024x1024, Steps: 4, Model: flux1-schnell.safetensors
|
||||
```
|
||||
|
||||
The filename format is `YYYYMMDD_HHMMSS_{seed}.png` — the seed is embedded so you can reproduce the exact image by passing it back as the `seed` parameter.
|
||||
|
||||
### Item 2 — `ImageContent` (inline base64 PNG)
|
||||
|
||||
The image displays **directly in Roo Code / Claude Desktop chat** as an inline image — no need to open a file browser. The same PNG is also saved to disk at the path shown in the TextContent.
|
||||
|
||||
```json
|
||||
{
|
||||
"type": "image",
|
||||
"mimeType": "image/png",
|
||||
"data": "<base64-encoded PNG bytes>"
|
||||
}
|
||||
```
|
||||
|
||||
### Error responses
|
||||
|
||||
When ComfyUI is unreachable or an error occurs, only **one** `TextContent` is returned (no ImageContent):
|
||||
|
||||
```
|
||||
ComfyUI not reachable at http://localhost:8188. Start it with: python main.py --listen
|
||||
```
|
||||
|
||||
```
|
||||
Generation timed out after 120s. prompt_id=abc-123 — use get_generation_status to check
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 7. Environment Variables
|
||||
|
||||
Configure via environment variables in [`.roo/mcp.json`](../../.roo/mcp.json) or shell:
|
||||
|
||||
| Variable | Default | Description |
|
||||
|---|---|---|
|
||||
| `COMFYUI_URL` | `http://localhost:8188` | Base URL of the running ComfyUI REST API. Change this if ComfyUI runs on a different host or port. |
|
||||
| `IMAGE_OUTPUT_DIR` | `~/Pictures/mcp-generated` | Directory where generated PNG files are saved. Supports `~` expansion. Created automatically on first generation. |
|
||||
| `COMFYUI_TIMEOUT` | `120` | Maximum seconds to wait for a generation job before returning a timeout error. Increase for very large images or slow hardware. |
|
||||
|
||||
### Setting via shell
|
||||
|
||||
```bash
|
||||
export COMFYUI_URL="http://localhost:8188"
|
||||
export IMAGE_OUTPUT_DIR="/home/pplate/Pictures/ai-art"
|
||||
export COMFYUI_TIMEOUT="300"
|
||||
./run.sh
|
||||
```
|
||||
|
||||
### Setting via mcp.json env block
|
||||
|
||||
```json
|
||||
"mcp-image-gen": {
|
||||
"command": "uv",
|
||||
"args": ["--directory", "/home/pplate/pi_mcps/mcp/mcp-image-gen", "run", "src/server.py"],
|
||||
"env": {
|
||||
"COMFYUI_URL": "http://localhost:8188",
|
||||
"IMAGE_OUTPUT_DIR": "/home/pplate/Pictures/mcp-generated",
|
||||
"COMFYUI_TIMEOUT": "120"
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 8. Test Status
|
||||
|
||||
**19 pytest tests — all passing.** Tests mock all ComfyUI HTTP calls using [respx](https://lundberg.github.io/respx/). No running ComfyUI instance is needed to run the tests.
|
||||
|
||||
```bash
|
||||
cd /home/pplate/pi_mcps/mcp/mcp-image-gen
|
||||
uv run pytest tests/ -v
|
||||
```
|
||||
|
||||
### Test coverage breakdown
|
||||
|
||||
| Test file | Tests | Coverage area |
|
||||
|---|---|---|
|
||||
| [`tests/test_server.py`](tests/test_server.py) | 19 | All 4 tools + workflow builder |
|
||||
|
||||
| Test name | What it verifies |
|
||||
|---|---|
|
||||
| `test_build_flux_workflow_structure` | Workflow has correct node class_types |
|
||||
| `test_build_flux_workflow_params_injected` | All params injected into correct nodes |
|
||||
| `test_negative_prompt_included` | Negative prompt goes to node 33 |
|
||||
| `test_random_seed_generated` | `seed=-1` produces a valid integer in `_meta` |
|
||||
| `test_list_available_models` | Returns model list from mocked `/object_info` |
|
||||
| `test_list_available_models_comfyui_offline` | ConnectError → graceful error string |
|
||||
| `test_get_generation_status_pending` | `prompt_id` in queue_pending → `"pending"` |
|
||||
| `test_get_generation_status_running` | `prompt_id` in queue_running → `"running"` |
|
||||
| `test_get_generation_status_complete` | Not in queue + in history → `"completed"` |
|
||||
| `test_get_output_directory_default` | No env var → `~/Pictures/mcp-generated` expanded |
|
||||
| `test_get_output_directory_custom` | Custom env var → that path returned |
|
||||
| `test_generate_image_success` | Full lifecycle: queue→poll→history→view→save |
|
||||
| `test_generate_image_comfyui_unavailable` | ConnectError → single TextContent error |
|
||||
| `test_generate_image_timeout` | COMFYUI_TIMEOUT=0 → timeout TextContent |
|
||||
| `test_generate_image_empty_prompt` | Empty string prompt → still succeeds |
|
||||
| `test_generate_image_long_prompt` | 500-char prompt → not truncated, succeeds |
|
||||
| `test_generate_image_invalid_model` | 404 from /prompt → error TextContent, no file saved |
|
||||
| `test_generate_image_custom_output_dir` | Custom `output_dir` param → saved there, dir created |
|
||||
| `test_generate_image_random_seed_variance` | `seed=-1` × 2 → different seeds, different filenames |
|
||||
|
||||
### Test mock stack
|
||||
|
||||
- **[respx](https://lundberg.github.io/respx/)** — HTTP-level mocking for all ComfyUI API endpoints
|
||||
- **[Pillow](https://pillow.readthedocs.io/)** (in conftest) — generates real PNG bytes for image response fixtures
|
||||
- **monkeypatch** — env vars (`IMAGE_OUTPUT_DIR`, `COMFYUI_URL`, `COMFYUI_TIMEOUT`) and server module attributes
|
||||
|
||||
Real image generation requires ComfyUI to be running. Tests prove the tool logic is correct at the protocol level.
|
||||
|
||||
---
|
||||
|
||||
## 9. Prompt Tips for FLUX.1-schnell
|
||||
|
||||
FLUX.1-schnell is a guidance-distilled model designed for speed at 1–8 steps. It responds differently from SDXL or SD1.5.
|
||||
|
||||
### Prompt structure that works well
|
||||
|
||||
```
|
||||
[subject], [style/medium], [lighting], [camera/composition], [mood/atmosphere], [quality modifiers]
|
||||
```
|
||||
|
||||
**Example:**
|
||||
```
|
||||
ancient library at night, oil painting, warm candlelight, wide angle, mysterious atmosphere, highly detailed, sharp focus
|
||||
```
|
||||
|
||||
### Style keywords
|
||||
|
||||
| Style | Prompt keywords |
|
||||
|---|---|
|
||||
| Photography | `cinematic photograph, DSLR, 85mm lens, shallow depth of field, bokeh` |
|
||||
| Oil painting | `oil painting, thick brushstrokes, textured canvas, impressionist` |
|
||||
| Watercolor | `watercolor painting, soft washes, paper texture, flowing colors` |
|
||||
| Digital art | `digital art, concept art, artstation, octane render` |
|
||||
| Anime/illustration | `anime style, cel shading, vibrant colors, clean linework` |
|
||||
| Sketch | `pencil sketch, hand drawn, crosshatching, charcoal` |
|
||||
|
||||
### Lighting keywords
|
||||
|
||||
- `golden hour`, `blue hour`, `dramatic lighting`, `rim lighting`
|
||||
- `studio lighting`, `soft diffused light`, `volumetric light`
|
||||
- `neon glow`, `bioluminescent`, `moonlit`, `candlelight`
|
||||
|
||||
### What works well with FLUX.1-schnell
|
||||
|
||||
- **Clear subject + style** — "red panda in a cozy library, watercolor style"
|
||||
- **Landscape scenes** — fjords, forests, cities, abstract environments
|
||||
- **Portrait shots** — animals and characters with descriptive appearance
|
||||
- **Concept art** — futuristic cities, sci-fi environments, fantasy scenes
|
||||
- **Low step counts** — 4 steps is designed to be near-optimal for this model
|
||||
|
||||
### What to avoid
|
||||
|
||||
- **Booru-style tag dumps** (FLUX handles natural language better than SD1.5)
|
||||
- **Contradictory instructions** — "dark AND bright", "realistic AND cartoon"
|
||||
- **Overly complex scenes** at very small resolutions
|
||||
|
||||
### Using the negative prompt
|
||||
|
||||
FLUX.1-schnell has reduced CFG guidance so negative prompts have less impact than in SDXL.
|
||||
Use them for broad exclusions:
|
||||
|
||||
```
|
||||
negative_prompt="blurry, out of focus, watermark, text, signature, low quality, artifacts"
|
||||
```
|
||||
|
||||
### Reproducibility
|
||||
|
||||
Always save the seed from the TextContent output if you want to reproduce a result:
|
||||
|
||||
```
|
||||
Seed: 3847291045
|
||||
```
|
||||
|
||||
Then pass it back: `seed=3847291045`
|
||||
|
||||
---
|
||||
|
||||
## 10. Known Limitations
|
||||
|
||||
### ComfyUI must run locally
|
||||
|
||||
The MCP server connects to `COMFYUI_URL` (default: `http://localhost:8188`). ComfyUI is a local application — it does not have a cloud API. You must start it before requesting image generation. The server returns a clear error message if ComfyUI is not reachable.
|
||||
|
||||
### Model must be pre-loaded
|
||||
|
||||
ComfyUI loads checkpoint models into VRAM on first use. The first generation with a model takes longer as VRAM is allocated (FLUX.1-schnell: ~8GB). Subsequent generations with the same model are faster.
|
||||
|
||||
```bash
|
||||
# Verify model is installed before generation
|
||||
# → ask Lumen: "list available models in ComfyUI"
|
||||
```
|
||||
|
||||
### AMD ROCm setup complexity
|
||||
|
||||
AMD GPU support requires:
|
||||
1. ROCm drivers installed (`rocm-smi` working)
|
||||
2. PyTorch built with ROCm support (not the default CUDA build)
|
||||
3. `HSA_OVERRIDE_GFX_VERSION=11.0.0` for RX 7900 XTX (gfx1100)
|
||||
|
||||
Without these, ComfyUI will fall back to CPU — very slow (minutes per image vs. ~8 seconds on RX 7900 XTX).
|
||||
|
||||
Check GPU is being used:
|
||||
```bash
|
||||
# In another terminal while generating:
|
||||
watch -n 1 rocm-smi
|
||||
# VRAM usage should spike to ~8GB during generation
|
||||
```
|
||||
|
||||
### Timeout on large images
|
||||
|
||||
The default `COMFYUI_TIMEOUT=120` (2 minutes) may not be enough for:
|
||||
- Very large resolutions (2048×2048+)
|
||||
- High step counts (20+)
|
||||
- First generation loading a new model
|
||||
|
||||
Increase via env var:
|
||||
```bash
|
||||
export COMFYUI_TIMEOUT=300 # 5 minutes
|
||||
```
|
||||
|
||||
If `generate_image` returns a timeout error, the job may still be running in ComfyUI. Use `get_generation_status(prompt_id)` to check.
|
||||
|
||||
### Ollama image gen is macOS-only (April 2026)
|
||||
|
||||
Ollama launched experimental image generation in January 2026, but it is **macOS-only** as of April 2026. Linux support is announced as "coming soon." When Linux support arrives, the server can switch backends via `IMAGE_BACKEND=ollama` without changing any tool signatures.
|
||||
|
||||
### ComfyUI history is ephemeral
|
||||
|
||||
ComfyUI keeps generation history in memory — it is lost on restart. The `get_generation_status` tool will return `"not_found"` for old prompt IDs after a ComfyUI restart. The saved PNG file on disk persists regardless.
|
||||
@@ -28,7 +28,6 @@ COMFYUI_BASE = "http://test-comfyui:8188"
|
||||
# build_flux_workflow — pure function, no mocking needed
|
||||
# ---------------------------------------------------------------------------
|
||||
|
||||
|
||||
def test_build_flux_workflow_structure():
|
||||
"""Verify build_flux_workflow returns a dict with correct node types."""
|
||||
wf = build_flux_workflow(
|
||||
@@ -103,7 +102,6 @@ def test_random_seed_generated():
|
||||
# list_available_models
|
||||
# ---------------------------------------------------------------------------
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_list_available_models():
|
||||
@@ -146,7 +144,6 @@ async def test_list_available_models_comfyui_offline():
|
||||
# get_generation_status
|
||||
# ---------------------------------------------------------------------------
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_get_generation_status_pending(queue_with_pending):
|
||||
@@ -191,7 +188,6 @@ async def test_get_generation_status_complete(queue_empty, mock_history_response
|
||||
# get_output_directory
|
||||
# ---------------------------------------------------------------------------
|
||||
|
||||
|
||||
def test_get_output_directory_default(monkeypatch):
|
||||
"""No IMAGE_OUTPUT_DIR env var → returns expanded ~/Pictures/mcp-generated."""
|
||||
monkeypatch.delenv("IMAGE_OUTPUT_DIR", raising=False)
|
||||
@@ -216,7 +212,6 @@ def test_get_output_directory_custom(monkeypatch, tmp_path):
|
||||
# generate_image
|
||||
# ---------------------------------------------------------------------------
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_generate_image_success(
|
||||
@@ -300,3 +295,253 @@ async def test_generate_image_timeout(monkeypatch, queue_with_pending):
|
||||
assert len(result) == 1
|
||||
assert "timed out" in result[0].text.lower()
|
||||
assert "test-uuid-1234" in result[0].text
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_generate_image_empty_prompt(tmp_path, sample_image_bytes, mock_history_response, queue_empty, monkeypatch):
|
||||
"""Empty prompt → workflow has empty text in positive node, but generation succeeds."""
|
||||
monkeypatch.setattr(server, "IMAGE_OUTPUT_DIR", str(tmp_path))
|
||||
|
||||
respx.post(f"{COMFYUI_BASE}/api/prompt").mock(
|
||||
return_value=httpx.Response(200, json={"prompt_id": "test-empty-uuid"})
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/queue").mock(
|
||||
return_value=httpx.Response(200, json=queue_empty)
|
||||
)
|
||||
mock_history_empty = {
|
||||
"test-empty-uuid": {
|
||||
"outputs": {
|
||||
"9": {
|
||||
"images": [
|
||||
{
|
||||
"filename": "mcp-image-gen_00001_.png",
|
||||
"subfolder": "",
|
||||
"type": "output",
|
||||
}
|
||||
]
|
||||
}
|
||||
},
|
||||
"status": {"completed": True},
|
||||
}
|
||||
}
|
||||
respx.get(f"{COMFYUI_BASE}/api/history/test-empty-uuid").mock(
|
||||
return_value=httpx.Response(200, json=mock_history_empty)
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/view").mock(
|
||||
return_value=httpx.Response(200, content=sample_image_bytes)
|
||||
)
|
||||
|
||||
result = await generate_image(prompt="", output_dir=str(tmp_path))
|
||||
|
||||
assert len(result) == 2
|
||||
text_content = result[0]
|
||||
image_content = result[1]
|
||||
assert "Generated:" in text_content.text
|
||||
assert str(tmp_path) in text_content.text
|
||||
# Verify workflow was built with empty prompt (indirectly via success)
|
||||
assert image_content.mimeType == "image/png"
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_generate_image_long_prompt(tmp_path, sample_image_bytes, mock_history_response, queue_empty, monkeypatch):
|
||||
"""Very long prompt → passed as-is to workflow without truncation."""
|
||||
monkeypatch.setattr(server, "IMAGE_OUTPUT_DIR", str(tmp_path))
|
||||
|
||||
long_prompt = "a " + "very long descriptive prompt " * 50 # ~500 chars
|
||||
|
||||
respx.post(f"{COMFYUI_BASE}/api/prompt").mock(
|
||||
return_value=httpx.Response(200, json={"prompt_id": "test-long-uuid"})
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/queue").mock(
|
||||
return_value=httpx.Response(200, json=queue_empty)
|
||||
)
|
||||
mock_history_long = {
|
||||
"test-long-uuid": {
|
||||
"outputs": {
|
||||
"9": {
|
||||
"images": [
|
||||
{
|
||||
"filename": "mcp-image-gen_00001_.png",
|
||||
"subfolder": "",
|
||||
"type": "output",
|
||||
}
|
||||
]
|
||||
}
|
||||
},
|
||||
"status": {"completed": True},
|
||||
}
|
||||
}
|
||||
respx.get(f"{COMFYUI_BASE}/api/history/test-long-uuid").mock(
|
||||
return_value=httpx.Response(200, json=mock_history_long)
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/view").mock(
|
||||
return_value=httpx.Response(200, content=sample_image_bytes)
|
||||
)
|
||||
|
||||
result = await generate_image(prompt=long_prompt, output_dir=str(tmp_path))
|
||||
|
||||
assert len(result) == 2
|
||||
# Success implies long prompt was accepted (ComfyUI handles it)
|
||||
saved_files = list(tmp_path.glob("*.png"))
|
||||
assert len(saved_files) == 1
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_generate_image_invalid_model(tmp_path, monkeypatch):
|
||||
"""Invalid model → ComfyUI /prompt returns 500 or 404, tool returns error TextContent."""
|
||||
monkeypatch.setattr(server, "IMAGE_OUTPUT_DIR", str(tmp_path))
|
||||
|
||||
respx.post(f"{COMFYUI_BASE}/api/prompt").mock(
|
||||
return_value=httpx.Response(404, json={"error": "Model not found"})
|
||||
)
|
||||
|
||||
result = await generate_image(
|
||||
prompt="a cat",
|
||||
model="nonexistent-model.safetensors",
|
||||
output_dir=str(tmp_path)
|
||||
)
|
||||
|
||||
assert len(result) == 1
|
||||
assert "404" in result[0].text
|
||||
assert "Model not found" in result[0].text
|
||||
# No file saved
|
||||
saved_files = list(tmp_path.glob("*.png"))
|
||||
assert len(saved_files) == 0
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_generate_image_custom_output_dir(tmp_path, sample_image_bytes, mock_history_response, queue_empty, monkeypatch):
|
||||
"""Custom output_dir → image saved there, path reflects it."""
|
||||
custom_dir = tmp_path / "custom"
|
||||
monkeypatch.setattr(server, "IMAGE_OUTPUT_DIR", str(tmp_path)) # Base for default
|
||||
|
||||
respx.post(f"{COMFYUI_BASE}/api/prompt").mock(
|
||||
return_value=httpx.Response(200, json={"prompt_id": "test-custom-uuid"})
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/queue").mock(
|
||||
return_value=httpx.Response(200, json=queue_empty)
|
||||
)
|
||||
mock_history_custom = {
|
||||
"test-custom-uuid": {
|
||||
"outputs": {
|
||||
"9": {
|
||||
"images": [
|
||||
{
|
||||
"filename": "mcp-image-gen_00001_.png",
|
||||
"subfolder": "",
|
||||
"type": "output",
|
||||
}
|
||||
]
|
||||
}
|
||||
},
|
||||
"status": {"completed": True},
|
||||
}
|
||||
}
|
||||
respx.get(f"{COMFYUI_BASE}/api/history/test-custom-uuid").mock(
|
||||
return_value=httpx.Response(200, json=mock_history_custom)
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/view").mock(
|
||||
return_value=httpx.Response(200, content=sample_image_bytes)
|
||||
)
|
||||
|
||||
result = await generate_image(
|
||||
prompt="a dog",
|
||||
output_dir=str(custom_dir),
|
||||
)
|
||||
|
||||
assert len(result) == 2
|
||||
text_content = result[0]
|
||||
assert str(custom_dir) in text_content.text
|
||||
# Directory was created
|
||||
assert custom_dir.exists()
|
||||
saved_files = list(custom_dir.glob("*.png"))
|
||||
assert len(saved_files) == 1
|
||||
|
||||
|
||||
@respx.mock
|
||||
@pytest.mark.asyncio
|
||||
async def test_generate_image_random_seed_variance(tmp_path, sample_image_bytes, mock_history_response, queue_empty, monkeypatch):
|
||||
"""seed=-1 → different actual_seed each call, reflected in filename."""
|
||||
monkeypatch.setattr(server, "IMAGE_OUTPUT_DIR", str(tmp_path))
|
||||
|
||||
# First generation
|
||||
respx.post(f"{COMFYUI_BASE}/api/prompt").mock(
|
||||
return_value=httpx.Response(200, json={"prompt_id": "seed1-uuid"})
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/queue").mock(
|
||||
return_value=httpx.Response(200, json=queue_empty)
|
||||
)
|
||||
mock_history_seed1 = {
|
||||
"seed1-uuid": {
|
||||
"outputs": {
|
||||
"9": {
|
||||
"images": [
|
||||
{
|
||||
"filename": "mcp-image-gen_00001_.png",
|
||||
"subfolder": "",
|
||||
"type": "output",
|
||||
}
|
||||
]
|
||||
}
|
||||
},
|
||||
"status": {"completed": True},
|
||||
}
|
||||
}
|
||||
respx.get(f"{COMFYUI_BASE}/api/history/seed1-uuid").mock(
|
||||
return_value=httpx.Response(200, json=mock_history_seed1)
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/view").mock(
|
||||
return_value=httpx.Response(200, content=sample_image_bytes)
|
||||
)
|
||||
|
||||
result1 = await generate_image(prompt="cat", seed=-1, output_dir=str(tmp_path))
|
||||
seed1 = [line for line in result1[0].text.split("\n") if "Seed:" in line][0].split(": ")[1]
|
||||
filename1 = Path(result1[0].text.split("Generated: ")[1].split("\n")[0]).name
|
||||
assert "Seed:" in result1[0].text
|
||||
assert int(seed1) != 0 # Not default
|
||||
|
||||
# Reset mocks for second call
|
||||
respx.reset()
|
||||
respx.post(f"{COMFYUI_BASE}/api/prompt").mock(
|
||||
return_value=httpx.Response(200, json={"prompt_id": "seed2-uuid"})
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/queue").mock(
|
||||
return_value=httpx.Response(200, json=queue_empty)
|
||||
)
|
||||
mock_history_seed2 = {
|
||||
"seed2-uuid": {
|
||||
"outputs": {
|
||||
"9": {
|
||||
"images": [
|
||||
{
|
||||
"filename": "mcp-image-gen_00002_.png",
|
||||
"subfolder": "",
|
||||
"type": "output",
|
||||
}
|
||||
]
|
||||
}
|
||||
},
|
||||
"status": {"completed": True},
|
||||
}
|
||||
}
|
||||
respx.get(f"{COMFYUI_BASE}/api/history/seed2-uuid").mock(
|
||||
return_value=httpx.Response(200, json=mock_history_seed2)
|
||||
)
|
||||
respx.get(f"{COMFYUI_BASE}/api/view").mock(
|
||||
return_value=httpx.Response(200, content=sample_image_bytes)
|
||||
)
|
||||
|
||||
result2 = await generate_image(prompt="cat", seed=-1, output_dir=str(tmp_path))
|
||||
seed2 = [line for line in result2[0].text.split("\n") if "Seed:" in line][0].split(": ")[1]
|
||||
filename2 = Path(result2[0].text.split("Generated: ")[1].split("\n")[0]).name
|
||||
|
||||
# Different seeds and filenames
|
||||
assert seed1 != seed2
|
||||
assert filename1 != filename2
|
||||
# Both saved
|
||||
saved_files = list(tmp_path.glob("*.png"))
|
||||
assert len(saved_files) == 2
|
||||
|
||||
Reference in New Issue
Block a user