Extensions/🪿 Browser Prompt Enhancer
ComfyUI Extension

🪿 Browser Prompt Enhancer

Unofficial ComfyUI prompt enhancer using Brave Leo through local browser automation.

By hodgemann·Created 2 days ago·Updated 2 days ago· 0
hodgemann/ComfyUI-Browser-Prompt-Enhancer
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🪿 Browser Prompt Enhancer for ComfyUI

Enhance your image-generation prompts with the free Brave Leo assistant — which has real-time web search — running in a local Brave browser. This is an unofficial integration, unaffiliated with Brave. No API key, no API cost.

Two modes:

  • append — Leo searches the web and adds fresh, concrete visual detail to the end of your prompt, keeping your original intent intact.
  • rewrite — Leo searches the web and rewrites your idea into a fully optimized image-generation prompt.

Built on the ComfyUI V3 node API. Designed to be modular and extensible (new modes are a one-line registration).

How it works (and honest limitations — please read)

This node uses Playwright to drive Leo's full-page view at brave://leo-ai, type your request, wait for the streamed answer, and return it to your workflow.

A few things to understand up front:

  • It automates the full-page Leo, not the sidebar. The Leo sidebar is part of the browser's chrome (its app UI) and cannot be reached by page automation. The full-page view is normal DOM, so that's what we drive.
  • Runs invisibly by default. window_mode defaults to headless (a real browser engine with no window), so nothing pops up. Set it to visible if you want to watch, or hidden to try an off-screen window. (Off-screen hiding is unreliable on Wayland/WSLg, which is why headless is the default.)
  • Visible mode needs a display. The default headless mode does not. On WSL2 + Windows 11, WSLg provides a display for visible mode (see below).
  • This is UI automation of an app not built to be automated, so it is inherently fragile. A Brave update can change Leo's markup. When that happens you'll get a clear error, and the fix is usually a selector update in brave_leo_core.py (SELECTORS). The browser flow was tested on WSL2 in October 2026.
  • Graceful by default. If Leo can't be reached, the node returns your original prompt unchanged plus a status message, so your workflow keeps running.

Prerequisites

  1. Brave Browser — install from https://brave.com/download/. Free Leo requires no account. (On WSL2, install the Linux Brave inside WSL2 — see below.)
  2. Playwright — installed automatically via requirements.txt. The node launches your installed Brave, so Playwright's bundled Chromium download is not needed.

Installation

Option A — ComfyUI Manager (easiest, once published)

  1. Open ComfyUI → Manager → Custom Nodes Manager.
  2. Search for Browser Prompt Enhancer and click Install.
  3. Open a terminal in the same Python environment ComfyUI uses and run: 
    # Linux/WSL2 only, if the self-test reports missing browser libraries:
playwright install-deps chromium
  4. Restart ComfyUI.

Option B — Manual (git clone)

cd ComfyUI/custom_nodes
git clone https://github.com/hodgemann/ComfyUI-Browser-Prompt-Enhancer
cd ComfyUI-Browser-Prompt-Enhancer
pip install -r requirements.txt
# Linux/WSL2 only, if needed:
playwright install-deps chromium

Restart ComfyUI. The node appears under Add Node → Browser Prompt Enhancer → Browser Prompt Enhancer.

WSL2 + Windows 11 setup (important if that's you)

ComfyUI runs inside WSL2 (Linux), but your everyday Brave is a Windows app — and a Linux Playwright process cannot drive a Windows .exe. The reliable approach is to install a Linux Brave inside WSL2 and let WSLg (built into Windows 11) display it on your Windows desktop. The node then launches/closes its own visible Brave window.

# Inside your WSL2 shell:

# 1) Install the Linux Brave
sudo apt update && sudo apt install -y curl
curl -fsS https://dl.brave.com/install.sh | sh
#    (alternative methods: https://brave.com/linux/)

# 2) Make sure ComfyUI's Python env has Playwright + browser deps
pip install -r requirements.txt
playwright install-deps chromium      # pulls the system libraries Chromium needs

# 3) Verify everything end-to-end
python selftest.py --full

Notes:

  • Start ComfyUI from an interactive WSL shell so the WSLg display variables (DISPLAY / WAYLAND_DISPLAY) are present. If you run ComfyUI as a background service without them, the node can't open a window. selftest.py checks this for you.
  • The dedicated Brave profile is created at ~/.comfyui-braveleo/profile. On the very first run, Leo may show a one-time consent screen. The node tries to dismiss it automatically; if it can't, run python selftest.py --window-mode visible once and click through by hand — the profile remembers it afterward.

Usage

Add Browser Prompt Enhancer, type a prompt, pick a mode, and connect enhanced_prompt to your CLIP Text Encode (or wherever your prompt goes).

The example workflow uses “A puppy dog sniffing a flower.” (the maintainer's preferred public SFW sample prompt) and the model-agnostic default personality. Queue it to preview Leo's result. It contains no checkpoint or LoRA names. To use it for images, connect your existing CLIP output to CLIP Text Encode and route its conditioning into your image workflow.

Inputs

| Input | Required | Description | |---|---|---| | original_prompt | ✅ | Your base prompt (multiline). Returned unchanged if Leo can't be reached. | | mode | ✅ | rewrite (full optimization; default) or append (add one sentence, keep intent). | | search_topic | optional | What Leo should search for. Empty → uses the original prompt. | | leo_personality | optional | A model-agnostic instruction prepended to the request (multiline; edit freely). | | connection_mode | advanced | managed (launch a dedicated Brave window — default) or attach (use a running Brave). | | window_mode | advanced | headless (no window — default, fully invisible), hidden (off-screen; may still show on Wayland/WSLg), or visible (debugging). managed only. | | timeout_seconds | advanced | How long to wait for Leo's full response (default 90). | | brave_path | advanced | Override the Brave executable path. Empty → auto-detect. | | debug_host / debug_port | advanced | attach mode only (see below). |

Outputs

| Output | Description | |---|---| | enhanced_prompt | The cleaned result (or your original prompt on failure). Wire this onward. | | raw_response | Leo's full, unmodified reply — handy for debugging. | | status | Success or a clear error message. |

Examples

append — original_prompt: "A futuristic city street.", search_topic: "2026 solarpunk city design" → "A futuristic city street, lined with solar-panel vertical gardens, holographic transit signage, and rain-slick reflective pavement."

rewrite — original_prompt: "Cat warrior." → "A hyper-detailed portrait of a feline knight in ornate engraved armor, battle-worn fur, glowing amber eyes, dramatic cinematic lighting, intricate metalwork, fantasy concept art, highly detailed, 8k."

Recovering past prompts from Leo's history

Every run is saved as a conversation in Leo's history inside the dedicated profile, so older enhanced prompts aren't lost. Two ways to get them back:

Open the dedicated profile directly to browse Leo's full conversation history:

brave-browser --user-data-dir="$HOME/.comfyui-braveleo/profile" "brave://leo-ai/"

Verifying it works (self-test)

Run this from the node folder, in ComfyUI's Python environment:

python selftest.py            # environment + Playwright + Brave + launch + open Leo
python selftest.py --full     # also send a tiny prompt and print Leo's reply
python selftest.py --full --window-mode visible   # watch the window while it happens
python selftest.py --debug    # on failure, dump live HTML + a screenshot for selector fixes

A green PASS on every line means the node should work in ComfyUI.

Advanced: attach mode (reuse your own Brave session)

Instead of a dedicated profile, you can attach to a Brave you launched yourself:

brave-browser --remote-debugging-port=9222 --remote-allow-origins=*

Then set the node's connection_mode to attach (and debug_port to match). --remote-allow-origins=* is required by modern Chromium for CDP connections.

WSL2 → Windows Brave: this only works if WSL2 can reach Windows' localhost. Enable mirrored networking (Windows 11): put the following in C:\Users\<you>\.wslconfig, then wsl --shutdown:

[wsl2]
networkingMode=mirrored

This path is experimental and finicky; managed mode is recommended.

Troubleshooting

| Symptom | Fix | |---|---| | BraveNotFoundError | Install Brave (https://brave.com/download/); on WSL2 install the Linux Brave inside WSL2. Or set brave_path. | | PlaywrightMissingError | pip install playwright. | | DisplayUnavailableError | Use headless mode or start ComfyUI with a working display. | | Driver fails to start (Linux/WSL2) | playwright install-deps chromium. | | LeoUIError: could not find Leo's input | A consent screen is up, or Brave changed its UI. Run selftest.py --window-mode visible (click through once) or --debug (then update SELECTORS in brave_leo_core.py). | | LeoTimeoutError | Raise timeout_seconds; check your network; run selftest.py --full --window-mode visible to watch. | | Leo asks you to sign in | Free Leo doesn't require an account; just complete any first-run prompt once in the dedicated profile. |

Publishing (maintainer notes)

See BEST_PRACTICES.md for the full developer guide, and the Publishing to the Comfy Registry section there for step-by-step instructions to get this into ComfyUI Manager.

Links

License

MIT — see LICENSE.