A small harness for iterating on recipe settings against the real Krea 2 model fast, using a mixture of agent tiers: cheap agents do the mechanical rendering; a stronger model judges whether the result achieves the recipe's intent. It turns "change a number, guess if it's better" into "change a number, render it, and get a scored verdict from images."

Pieces

File	Role	Who runs it
tweak_test.py	Render engine: given a recipe (built-in label or a full tweak bundle) + reference + prompt + strength + seed, renders on the ComfyUI box and prints `{name, image, metrics}` as JSON. Pure mechanical work, no judgment.	a cheap agent (Haiku), or you directly
style_transfer_stack_test.py	Multi-card V10 style-transfer harness: content anchor + style reference + optional away-layout guard. Used to test the repeatable style-transfer method in v10-style-transfer-method.md.	maintainer
style_transfer_reliability_suite.py	Fixed V10 style-transfer regression matrix: six content/style stress cases across the default and leak-control methods, with JSONL metrics and a contact sheet.	maintainer
style_transfer_seed_sweep.py	Seed-stability check for the recommended V10 style-transfer methods: three stress cases, two methods, three seeds each, with JSONL metrics and a contact sheet.	maintainer
the `recipe-tweak-test` workflow	Orchestrates: for each recipe, Haiku agents render the current settings + candidate tweaks in parallel, then a Fable agent reads the images and scores each against the recipe's stated intent, names the best, and recommends a change.	the Workflow tool
generate_guide_demos.py	Renders the V10 user-guide demo set (every recipe + the journeys) with the matching drag-in V10 workflow embedded in each PNG, and rebuilds the guide manifest + recipe-gallery contact sheet in `docs/assets/krea-v10/demos/`. `--only <slugs>` re-renders a subset; `--skip-render` rebuilds manifest/sheet only.	maintainer
refs/	Local copies of reference images so the judge agent can see them.	-
runs/	Local copies of every rendered variant (also saved on the box under `output/claude-generations/recipe-lab/`).	-

Gotcha: dropping a brand-new custom recipe label onto the box races ComfyUI's node-definition cache - the first /prompt after the drop can 400. Retry once (or hit /object_info/KGKrea2ImageGuideCardV10 first to force a refresh).

The loop

Define the job: the recipe label, its intent in one sentence (what it should do and what it must NOT overstep), a reference image, a content prompt, and a list of variants to compare (the current recipe plus any tweaks - a tweak is a full recipe bundle, e.g. a different layers array or global).
Render (cheap): one Haiku agent per variant runs tweak_test.py. Renders serialize on the single GPU but the agent orchestration is free.
Judge (capable): one Fable agent Reads all the variant images + the reference and scores them 0-10 against the intent, picks the best, and recommends a concrete settings change if the current recipe underperforms.
Act: apply the winning/recommended settings, re-run to confirm, commit.

Run it

Directly (one render):

python docs/recipe-lab/tweak_test.py --builtin "suggest the visual style" \
  --ref layerprobe2/base.png --prompt "a plain white bowl on a wooden table" \
  --strength 0.6 --seed 424242 --name style-current

As the judged workflow: invoke the recipe-tweak-test workflow (it embeds a demo job set; pass args.jobs to test your own recipes/tweaks). Cheap agents render, Fable judges, and the run returns per-recipe verdicts.

Requirements

A running ComfyUI server (default http://127.0.0.1:8188) with the V10 nodes installed and the reference images in its input/ folder.
Renders and reference copies go to the dedicated claude-generations/ output folder; the harness only reads back what it generated.

You can point all recipe-lab scripts at another server without editing files:

KREA_COMFYUI_SERVER=http://192.0.2.10:8188 python docs/recipe-lab/tweak_test.py ...

Optional path overrides:

KREA_REFERENCE_REPO: repo root for the recipe-tweak-test workflow.
KREA_REFERENCE_SCRATCH: scratch folder for temporary recipe JSON from that workflow. Defaults to docs/recipe-lab/runs/scratchpad.
KREA_REFERENCE_CUSTOM_RECIPES: where lab recipe JSON files are written for ComfyUI to discover. Defaults to the repo's custom_recipes/ folder, which is correct when this repo is installed as a ComfyUI custom node.
KREA_REFERENCE_STYLE_REFS: local folder for the style-transfer reliability reference images. Defaults to docs/recipe-lab/refs/. The reliability suite will print the exact missing filenames if those larger public-domain stress references are not present in your checkout.
KREA_MODEL, KREA_CLIP, and KREA_VAE: ComfyUI model filenames if your local names differ from the defaults.

Maintainer tooling - lives under docs/ (excluded from registry packs).