ComfyUI ImageGen (Flux2)

Generate images via ComfyUI API (localhost:8188) using Flux2 workflow. Supports structured JSON prompts sent directly as positive prompt parameter, seed/steps customization. Async watcher via sub-agent for low-latency, token-efficient polling (every 5s).

Security Scan

The skill's files and runtime instructions are consistent with its stated purpose (submitting Flux2 workflows to a ComfyUI instance and downloading images); nothing in the package requests unrelated credentials or installs surprising binaries.

Purpose & Capability

Name/description match the included script and workflow: the Python script posts a Flux2 workflow JSON to a ComfyUI host, polls history, and downloads the saved JPG. There are no unexpected required env vars, binaries, or installers that would be unrelated to image generation.

Instruction Scope

SKILL.md stays largely within image-generation scope, but the examples include orchestration steps (sessions_spawn) that automatically send images via the agent's message tool (Telegram) and use a hardcoded example workspace path (C:\Users\hal\.openclaw\workspace). Those orchestration instructions reach into the agent's messaging/channel capabilities and the local filesystem; they are plausible but are external to core generation and deserve operator awareness.

Install Mechanism

No install spec is provided (instruction-only with a small included script), so nothing is downloaded or executed at install time. This minimizes supply-chain risk.

Credentials

The skill declares no environment variables or credentials, which matches its behavior (it talks to a ComfyUI HTTP host). However SKILL.md demonstrates auto-sending images to Telegram via the agent's message tool but does not declare Telegram credentials — this relies on the agent/runtime having messaging credentials configured. The example also references a user-specific workspace path; if followed, that grants the skill read/write in that folder.

Persistence & Privilege

The skill does not request permanent/always-on inclusion (always:false) and does not modify other skills or global agent settings. It uses a spawned watcher sub-agent in examples, which is normal for async jobs but not a privileged persistent presence.

Assessment

This skill appears to do what it says: submit a Flux2 workflow to a ComfyUI HTTP server (default localhost:8188), poll for completion, and download the saved image. Before installing/using: 1) ensure you trust the ComfyUI host you point it at (default is localhost; if you change --host to a remote server, your structured prompts and any metadata will be sent to that server), 2) be aware the SKILL.md examples auto-send images via the agent's message tool (Telegram) — confirm the agent's messaging channels/targets are ones you trust, 3) the example uses a user-specific workspace path for spawned jobs; modify that to a safe directory on your system if you run the watcher, and 4) the script writes downloaded images to disk and removes them in the example — check file paths and permissions you grant the agent. If you need stricter guarantees, run ComfyUI locally and avoid using the example sessions_spawn Telegram send until you verify messaging credentials and targets.

ComfyUI ImageGen\n\n## Changelog\n- [2026-02-11 20:42 EST]: v1.5.0 (published) - Standalone --structured-prompt fix (no positional arg required); workflow updated to 1920x1080 16:9; production-ready with live tests (JSON direct-to-positive-prompt, async sub-agent delivery).\n- [2026-02-11 10:10 EST]: v1.4.0 - Refactored prompting: agent converts human prompt to structured JSON string; script sends JSON directly as ComfyUI positive prompt (no prose conversion). Added text-in-image quoting rule.

Changelog

• [2026-02-11 10:10 EST]: v1.4.0 - Refactored prompting: agent converts human prompt to structured JSON string; script sends JSON directly as ComfyUI positive prompt (no prose conversion). Added text-in-image quoting rule.
• [2026-02-11 09:52 EST]: v1.3.0 - Script now accepts --structured-prompt JSON directly (auto-generates prose internally). Removed agent-side prose step. Updated usage/examples.
• [2026-02-11 09:20 EST]: v1.2.0 - Added structured prompt parsing: translate human requests into optional JSON schema fields, auto-generate optimized Flux.2 prose prompts. Updated description.
• [2026-02-11 00:15 EST]: v1.1.0 - Added --submit-only (fast prompt_id return) + --watch prompt_id modes. SKILL.md docs async flow: submit → sessions_spawn watcher sub-agent (polls every 5s, auto-sends image to Telegram, ~10x token savings vs. main-agent block).
• [2026-02-11 04:05 EST]: v1.0.3 - Added Flux.2 [klein] 9B prompting best practices section with guidelines from Black Forest Labs and fal.ai.
• [2026-02-10 23:05]: v1.0.2 - Workflow v3: "Image Save with Prompt/Info (WLSH)" (node 85) for improved metadata embedding. Script updated to poll node 85.
• [2026-02-10 23:00]: Added explicit instruction to always send generated image to user post-generation via message tool.
• [2026-02-10]: Updated to new workflow: JPG output with embedded prompt/metadata via "Image Save with Prompt File (WLSH)". Model changed to darkBeastFeb0826Latest_dbkBlitzV15.safetensors. Script now polls node 84.

Usage

1. Agent converts human request to mandatory structured JSON schema → compact string.

2. Verify ComfyUI runs on localhost:8188.

3. Async Mode (Recommended):

   1. exec python skills/comfyui-imagegen/scripts/generate.py --structured-prompt '{"subjects":[{"description":"fluffy tabby cat","position":"center","action":"sitting relaxed"}],"scene":"cozy room interior","lighting":"warm golden sunset rays","mood":"serene and peaceful","camera":{"angle":"low angle"}}' --submit-only → parse prompt_id
   2. sessions_spawn task="Set-Location 'C:\\Users\\hal\\.openclaw\\workspace'; python skills/comfyui-imagegen/scripts/generate.py --watch '{prompt_id}' --output ./gen-{prompt_id}.jpg; message action=send channel=telegram target=595846104 media=./gen-{prompt_id}.jpg; Remove-Item ./gen-{prompt_id}.jpg" label="img-{prompt_id}" cleanup=delete runTimeoutSeconds=180
   

   • Watcher polls /history/{prompt_id} every 5s (optimal: <5s latency, ~12 polls max @60s job, isolated tokens).
   • Auto-sends JPG to this chat on completion (sub-agent pings back).
   • Timeout implicitly via spawn runTimeoutSeconds=120.

4. Sync Mode (blocks agent):

   exec python skills/comfyui-imagegen/scripts/generate.py --structured-prompt '{"scene":"your scene"}' [--seed N] [--steps 10] [--output ./my.jpg] [--host localhost:8188]
   message action=send channel=telegram media=./my.jpg
   

5. Customize:

   Arg	Default	Notes
   --seed	random	Repro
   --steps	5	20-50 quality
   --host	localhost:8188	Remote
   --output	gen-{seed/pid}.jpg	Full path

Structured Prompt Schema (Mandatory Format)

Agent step 1: Convert human natural language request into this exact JSON structure (all fields optional; populate only relevant; subjects array supports multiples).

Rule: For text in images (signs, logos), surround in double quotes within description/action fields, e.g., "sign reading \"STOP\"" or "logo with text \"OpenClaw\""

{
  "scene": "overall scene description",
  "subjects": [
    {
      "description": "detailed subject description",
      "position": "where in frame",
      "action": "what they're doing"
    }
  ],
  "style": "artistic style",
  "color_palette": ["#FF0000", "#00AACC"],
  "lighting": "lighting description",
  "mood": "emotional tone",
  "background": "background details",
  "composition": "framing and layout",
  "camera": {
    "angle": "camera angle",
    "lens": "lens type",
    "depth_of_field": "focus behavior"
  }
}

Agent step 2: Stringify JSON (compact, single-line for shell escaping), pass to script --structured-prompt (sent directly as ComfyUI positive prompt).

Example:

User: "A cat sitting on a windowsill at sunset"

Structured JSON string (for --structured-prompt):

'{"subjects":[{"description":"fluffy tabby cat","position":"center","action":"sitting relaxed"}],"scene":"cozy room interior","lighting":"warm golden sunset rays","mood":"serene and peaceful","camera":{"angle":"low angle"}}'

Workflow Details

• Polls node 85 ("Image Save with Prompt/Info (WLSH)").
• Model: darkBeastFeb0826Latest_dbkBlitzV15.safetensors
• Template: workflows/flux2.json

Prompting Best Practices (Flux.2 [klein] 9B)

• Prose, not keywords. Subject → Scene → Lighting → Mood.
• E.g., "A serene mountain lake at dawn, mist rising, golden light piercing peaks, photorealistic."
• Sources: BFL, fal.ai

Examples

# Async test (structured JSON string → direct positive prompt)
python .../generate.py --structured-prompt '{"subjects":[{"description":"fluffy tabby cat","position":"center","action":"sitting relaxed"}],"scene":"cozy room interior","lighting":"warm golden sunset rays","mood":"serene and peaceful","camera":{"angle":"low angle"}}' --submit-only --steps 10
# → prompt_id=abc123; spawn watcher sub-agent

For cron alternative (less optimal): cron add one-shot at=now+10s payload.systemEvent="Check img job {prompt_id}" but spawn > cron for this.