diff --git a/.cursor/rules/single-place-functionality.mdc b/.cursor/rules/single-place-functionality.mdc
new file mode 100644
index 00000000..ad27b414
--- /dev/null
+++ b/.cursor/rules/single-place-functionality.mdc
@@ -0,0 +1,20 @@
+---
+description: No duplicated functionality — implement each behavior in one place only
+alwaysApply: true
+---
+
+# Single-place functionality
+
+Where something can be done in one place and functionality remains absolutely the same, it must be done in that single place.
+
+Duplicated functionality is prohibited unless strictly required for the process.
+
+## Examples
+
+- UI state that belongs on a timeline clip (e.g. "Generated with" stale-prompt hint) lives on the clip only — not repeated on the player overlay, inspector, or toolbar.
+- Shared logic belongs in one module/function; views call it instead of re-implementing.
+- If two call sites need the same behavior, extract once and reuse — do not copy-paste with drift.
+
+## When duplication is allowed
+
+Only when the process genuinely requires it (e.g. server validation mirroring client hints for security, or ComfyUI node vs Movie Editor entry points that cannot share a runtime).
diff --git a/movie_editor/frontend/inspector.js b/movie_editor/frontend/inspector.js
index 5abbf9a0..0b706394 100644
--- a/movie_editor/frontend/inspector.js
+++ b/movie_editor/frontend/inspector.js
@@ -164,13 +164,6 @@
     const ta = el("textarea"); ta.rows = 4; ta.value = root.text || ""; ta.placeholder = "Describe this scene…"; ta.dataset.k = "sc-text";
     ta.oninput = () => S.patchSceneQuiet(scene.id, { text: ta.value });
     body.append(field("Prompt", ta));
-    const promptMismatch = S.renderPromptMismatch ? S.renderPromptMismatch(scene.id) : null;
-    if (promptMismatch) {
-      const warn = el("div", "render-prompt-warn");
-      warn.append(el("div", "render-prompt-warn-title", "Preview was generated with a different prompt"));
-      warn.append(el("div", "render-prompt-text", promptMismatch.rendered || "(empty)"));
-      body.append(warn);
-    }
     const src = el("select");
     SRC.forEach(([v, label]) => { const o = el("option", null, label); o.value = v; if ((root.source?.type) === v) o.selected = true; src.append(o); });
     src.onchange = () => {
diff --git a/movie_editor/frontend/player.js b/movie_editor/frontend/player.js
index f7fe7ce4..4c781646 100644
--- a/movie_editor/frontend/player.js
+++ b/movie_editor/frontend/player.js
@@ -102,7 +102,6 @@
 
   let _slateEl = null;
   let _badgeEl = null;
-  let _promptEl = null;
   function _showSlate(title, sub) {
     if (!_slateEl) return;
     _slateEl.style.display = title ? "" : "none";
@@ -117,18 +116,6 @@
     _badgeEl.textContent = text || "";
     _badgeEl.style.display = text ? "" : "none";
   }
-  function _showRenderPrompt(sceneId) {
-    if (!_promptEl) return;
-    const mismatch = sceneId && S.renderPromptMismatch ? S.renderPromptMismatch(sceneId) : null;
-    if (!mismatch) {
-      _promptEl.style.display = "none";
-      _promptEl.textContent = "";
-      return;
-    }
-    _promptEl.style.display = "";
-    _promptEl.title = "Timeline prompt was edited after generation - rate against this text";
-    _promptEl.textContent = `Generated with: ${mismatch.rendered}`;
-  }
 
   // ── video pool management ─────────────────────────────────────────────────────
   function _ensureVideo(url) {
@@ -210,7 +197,6 @@
       _currentClip = clip;
       _setActive(null);
       _showBadge("");
-      _showRenderPrompt(null);
       _showSlate(clip.slate || "Not generated yet", clip.slateSub);
       if (play) _startTick();
       return;
@@ -221,7 +207,6 @@
     _showSlate("");
     const badge = clip.ghost ? (clip.slate || "Removed — preview only") : _segmentSourceBadge(clip.sceneId);
     _showBadge(badge);
-    _showRenderPrompt(clip.ghost ? null : clip.sceneId);
     if (_badgeEl && badge.startsWith("Mixed")) _badgeEl.classList.add("mixed-mode");
     else if (_badgeEl) _badgeEl.classList.remove("mixed-mode");
     const target = (clip.inSec || 0) + Math.max(0, offset);
@@ -512,14 +497,11 @@
     _slateEl.append(el("div", "pm-slate-sub"));
     _badgeEl = el("div", "pm-segment-badge");
     _badgeEl.style.display = "none";
-    _promptEl = el("div", "pm-render-prompt");
-    _promptEl.style.display = "none";
 
     if (_clips.length) {
       canvas.append(stage);  // pooled videos live here; only the active one is visible
       canvas.append(_slateEl);
       canvas.append(_badgeEl);
-      canvas.append(_promptEl);
     } else if (previewAsset?.kind === "image") {
       canvas.append(stage);
     } else if (["queuing", "running", "pending"].includes(gen.state)) {
diff --git a/movie_editor/frontend/styles.css b/movie_editor/frontend/styles.css
index 2cd5d8f2..67a0be3d 100644
--- a/movie_editor/frontend/styles.css
+++ b/movie_editor/frontend/styles.css
@@ -343,7 +343,7 @@ input[type=number] { font-family: var(--font-mono); }
 .pm-canvas.media-previewing .pm-stage,
 .pm-canvas.media-previewing .pm-slate,
 .pm-canvas.media-previewing .pm-segment-badge,
-.pm-canvas.media-previewing .pm-render-prompt { visibility: hidden; }
+.pm-canvas.media-previewing .pm-segment-badge { visibility: hidden; }
 .pm-media-preview { position: absolute; inset: 0; z-index: 5; display: flex; align-items: center; justify-content: center; cursor: default; }
 .pm-media-preview-img { max-width: 100%; max-height: 100%; object-fit: contain; position: relative; z-index: 1; cursor: default; }
 .pm-media-preview-label { position: absolute; top: 10px; left: 10px; z-index: 2; font-size: 10.5px; font-family: var(--font-mono); color: var(--teal); background: #000a; border: 1px solid color-mix(in srgb, var(--teal) 35%, var(--line)); border-radius: 12px; padding: 3px 9px; pointer-events: none; }
@@ -380,13 +380,6 @@ input[type=number] { font-family: var(--font-mono); }
 .pm-slate-title { font-size: 14px; color: var(--amber-2); font-family: var(--font-mono); }
 .pm-slate-sub { font-size: 11.5px; color: var(--faint); max-width: 280px; }
 .pm-segment-badge { position: absolute; top: 10px; left: 10px; z-index: 3; font-size: 10.5px; font-family: var(--font-mono); color: var(--amber-2); background: #000a; border: 1px solid color-mix(in srgb, var(--amber) 35%, var(--line)); border-radius: 12px; padding: 3px 9px; pointer-events: none; }
-.pm-render-prompt {
-  position: absolute; left: 10px; right: 10px; bottom: 10px; z-index: 3;
-  font-size: 10.5px; font-family: var(--font-mono); line-height: 1.35; color: #ffd9a0;
-  background: #000c; border: 1px solid color-mix(in srgb, var(--amber) 40%, var(--line));
-  border-radius: 10px; padding: 6px 10px; pointer-events: none;
-  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
-}
 .pm-needle { position: absolute; top: 0; bottom: 0; width: 2px; background: #fff; opacity: .85; transform: translateX(-50%); pointer-events: none; z-index: 2; }
 
 /* transport bar */
@@ -563,21 +556,6 @@ input[type=number] { font-family: var(--font-mono); }
 .me-rating-heart:hover { background: rgba(255,120,180,0.12); border-color: rgba(255,120,180,0.6); color: #ffb3d4; }
 .me-rating-heart.active { background: rgba(255,120,180,0.20); border-color: rgba(255,120,180,0.8); color: #ffb3d4; }
 .me-rating-nuclear { padding: 8px 10px; display: grid; grid-template-columns: 1fr 1fr; gap: 5px; }
-.tl-render-prompt {
-  font-family: var(--font-mono); font-size: 10px; color: var(--amber-2); opacity: .9;
-  max-width: 220px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
-  border: 1px solid color-mix(in srgb, var(--amber) 30%, var(--line)); border-radius: 6px; padding: 3px 7px;
-  background: color-mix(in srgb, var(--amber-soft) 35%, var(--ink-2));
-}
-.render-prompt-warn {
-  border: 1px solid color-mix(in srgb, var(--amber) 35%, var(--line));
-  background: color-mix(in srgb, var(--amber-soft) 25%, var(--ink-1));
-  border-radius: 8px; padding: 8px 10px; margin: -4px 0 12px;
-}
-.render-prompt-warn-title { font-size: 11.5px; color: var(--amber-2); margin-bottom: 6px; }
-.render-prompt-prev { display: flex; flex-direction: column; gap: 3px; margin-bottom: 6px; }
-.render-prompt-label { font-family: var(--font-mono); font-size: 10px; letter-spacing: .5px; text-transform: uppercase; color: var(--faint); }
-.render-prompt-text { font-size: 12px; color: var(--text); line-height: 1.4; white-space: pre-wrap; word-break: break-word; }
 
 .tl-scroll { flex: 1; overflow-x: auto; overflow-y: auto; position: relative; }
 .tl-stage { display: flex; flex-direction: row; height: 100%; min-height: 100%; }