Document seed-controlled Krea2 evals

docs/krea2-prompt-guide.md

@@ -26,6 +26,23 @@ Avoid letting two sections describe incompatible camera or framing intents.
 - Analysis, scoring, and generator notes belong in chat or `sxcp_eval_log`.
 - Keep one experiment variable per cycle when possible.
 - Lock seed, character, location, and camera when testing wording changes.
+- Treat the MCP seed as transport metadata. Preserve it for prompt-only A/B tests
+  and do not write it into the visible prompt text.
+
+## Seed-Controlled A/B Tests
+
+Use one fixed seed when deciding whether prompt wording helped Krea2. A single
+image can justify a prompt-only retry when the mismatch is obvious, but a
+generator rule needs either repeated evidence or a generated prompt that is
+structurally wrong before rendering.
+
+When reviewing an eval payload, log:
+
+- emitted seed,
+- original generated prompt,
+- edited prompt,
+- image failure or improvement,
+- whether the change should stay prompt-only or become a generator patch.
 
 ## Camera And Composition
 

docs/sxcp-eval-loop.md

@@ -1,15 +1,17 @@
 # SxCP Eval Loop
 
 This loop is for tuning the SxCP generator toward stronger Krea2 images.
-ComfyUI sends a generated prompt and image to Codex, Codex analyzes the result,
-then sends back exactly one edited prompt for the next A/B test. Confirmed
-findings become either generator changes or durable prompt rules in
+ComfyUI sends a generated prompt, image, and seed to Codex, Codex analyzes the
+result, then sends back exactly one edited prompt for the next A/B test.
+Confirmed findings become either generator changes or durable prompt rules in
 [`krea2-prompt-guide.md`](krea2-prompt-guide.md).
 
 ## Channels
 
-- `sxcp_eval_in`: ComfyUI to Codex. Contains the prompt text and image path.
-- `sxcp_eval_out`: Codex to ComfyUI. Prompt-only. Do not put analysis here.
+- `sxcp_eval_in`: ComfyUI to Codex. Contains the prompt text, image path, and
+  seed.
+- `sxcp_eval_out`: Codex to ComfyUI. Prompt-only text plus the same seed through
+  the MCP signal when supported. Do not put analysis here.
 - `sxcp_eval_log`: optional analysis/log channel.
 
 ## Manual Loop
@@ -23,12 +25,14 @@ tools/sxcp_eval_loop.sh 3
 Every three minutes it prints a structured request asking Codex to:
 
 1. Pull `sxcp_eval_in`.
-2. Inspect the image.
-3. Compare it to the prompt and previous edit.
-4. Push one prompt-only edit to `sxcp_eval_out`.
-5. Classify the finding as prompt-only, prompt-guide rule, or generator fix.
-6. Change generator code/data only when the issue is systemic.
-7. Record the finding and update the Krea2 prompt guide when a rule is confirmed.
+2. Record the emitted seed.
+3. Inspect the image.
+4. Compare it to the prompt and previous edit.
+5. Push one prompt-only edit to `sxcp_eval_out`, preserving the same seed through
+   the MCP signal when available.
+6. Classify the finding as prompt-only, prompt-guide rule, or generator fix.
+7. Change generator code/data only when the issue is systemic.
+8. Record the finding and update the Krea2 prompt guide when a rule is confirmed.
 
 Runtime logs are written under `.sxcp_eval/` and ignored by git.
 
@@ -60,8 +64,17 @@ The request is sent on stdin. The command also receives:
 - Crop/framing
 - Prompt noise/repetition
 - Model confusion tokens
+- Seed control/reproducibility
 - Overall Krea2 image usefulness
 
+## Seed Contract
+
+The seed is transport metadata, not prompt text. When the graph emits a seed, an
+A/B wording test should reuse that exact seed so the image difference mostly
+comes from wording, not sampling randomness. If a payload has no seed, mark that
+cycle as uncontrolled and avoid turning the result into a durable generator rule
+without another controlled run.
+
 ## Generator Fix Rule
 
 Only edit the generator when the image shows a repeatable, systemic prompt