[MehranMarxian]

What changed and why

Beta gate G4, finding 1. Live Painting's live tier is SD 1.5 plus the LCM LoRA, loaded through CheckpointLoaderSimple, but it took whatever the Text to Image Model dropdown held. Since v0.39 a starter install opens Text to Image on FLUX.2 Klein, a diffusion model in another folder. So on a fresh install every live cycle failed with "Live cycle failed (1/3 consecutive): The model flux-2-k…", and every new user would hit it.

The fix: chooseLivePaintingCheckpoint, a pure function in src/ui/tools/livePainting.ts with tests, picks the live checkpoint:

1. Text to Image's model, when ComfyUI lists it as a checkpoint and its name reads SD 1.x or gives no family. An SD 1.5 fine-tune with an unhelpful file name is the common case, and it worked before, so it's kept.
2. Otherwise the recommended epicrealism_naturalSinRC1VAE.safetensors, if installed.
3. Otherwise the first checkpoint whose name says SD 1.x.
4. Otherwise it doesn't start. It says: "Live Painting runs on an SD 1.5 checkpoint, and ComfyUI has none in models/checkpoints. Install one, for example epicrealism_naturalSinRC1VAE.safetensors, then start the session again."

When it uses another checkpoint, the status reads, for example: "Live Painting runs on SD 1.5, so it uses epicrealism_naturalSinRC1VAE.safetensors instead of flux-2-klein-4b-fp8.safetensors." Text to Image's own selection is never changed.

Panel text: the Live Painting hint (appMarkup.ts, text only, no CSS) now says this, instead of telling people to pick a model on Text to Image. The G4 row in docs/beta-gate.md notes the fix.

Verified

npm run typecheck   exit 0
npm run lint        exit 0
npm test            Test Files 141 passed (141), Tests 1387 passed (1387)
npm run build       "Copied UXP assets to dist."

tests/ui/livePaintingCheckpoint.test.ts (7 tests) covers:

• Klein falls back to epicRealism, with the message;
• an SD 1.5 model and an unknown-family model are kept;
• SDXL is not run live;
• with epicRealism missing, it uses the first SD 1.x checkpoint;
• with no SD 1.5 at all it refuses, in plain text;
• with no model selected it picks one.

Checked in Photoshop 2025 by Claude, after a reload, with Text to Image left on txt2img-flux2-klein (the exact failing case from the G4 run):

• Start Live Session, then paint a stroke. Cycles 1 to 3 succeeded, and the preview followed the stroke.
• ComfyUI's history shows all three cycles ran epicrealism_naturalSinRC1VAE.safetensors with the SD 1.5 LCM LoRA (lcm\SD1.5\pytorch_lora_weights.safetensors), status success.
• Text to Image was still on Klein afterwards.

Could NOT be verified

• The substitution note was barely visible. It shows only until the first cycle replaces the status line, which took about a second here.
• The "no SD 1.5 checkpoint" message wasn't seen in Photoshop: this machine has four SD 1.x checkpoints. The unit test covers it.

What Mehran should check in Photoshop

Smoke checklist blocks (docs/uxp-smoke-checklist.md):

• Block 0 (the panel starts)
• Block 5 (Live Painting)

Load: UXP Developer Tool › OpenLayer › Reload.

• 1. Text to Image › Workflow txt2img-flux2-klein. Then Home › Live Painting: read the new hint.
• 2. Start Live Session, paint two strokes on an empty layer. See: the preview updates; no "Live cycle failed".
• 3. Stop Live Session, then go back to Text to Image. See: still on Klein.

🤖 Generated with Claude Code