BigSimmo · BigSimmo · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026
@@ -76,7 +76,7 @@ structural change, not a single mixed PR.
 ### X3 · Decompose the monoliths — `IN PROGRESS`
 
 - **Outcome:** shrink the three files the maintainability ratchet caps but never reduces:
-  `src/lib/rag/rag.ts` (5,018), `src/components/ClinicalDashboard.tsx` (4,271),
+  `src/lib/rag/rag.ts` (5,018), `src/components/ClinicalDashboard.tsx` (was 4,271, now 4,157),
   `src/components/DocumentViewer.tsx` (was 3,164, now 1,733).
 - **Progress (#997):** extracted the evidence-gate predicates from `rag.ts` into
   `src/lib/rag/rag-evidence-gates.ts` (rag.ts 5,147 → 5,018), pure moves behind the existing
@@ -87,8 +87,14 @@ structural change, not a single mixed PR.
   behaviour-bearing `manual-tag-editor.tsx` (add/rename/delete manual labels), and
   `document-overview-landing.tsx`. The moves are verbatim (no logic changed); the container is
   now composition-focused — it retains the detail fetch, dynamic PDF loading, and state
-  orchestration (3,164 → 1,733, budget ratcheted to 1,733). `ClinicalDashboard.tsx` (4,271)
-  and `rag.ts` remain the open decomposition targets.
+  orchestration (3,164 → 1,733, budget ratcheted to 1,733).
+- **Progress (`ClinicalDashboard.tsx`):** the dashboard was already heavily decomposed (72
+  `clinical-dashboard/*` modules), so this is an incremental ratchet — extracted the
+  self-contained answer-thread turn leaf (`AnswerTurn` type, `maxVisiblePriorTurns`, and the
+  `PriorAnswerTurnSurface` component) into `clinical-dashboard/answer-thread-turn.tsx` as a
+  verbatim move (4,271 → 4,157, budget ratcheted to 4,157). The residual is a tightly-coupled
+  orchestrator core; further safe extractions are smaller, incremental units. `rag.ts` remains
+  the largest open target.
 - **Approach:** extract cohesive units behind the existing budgets; the components decompose
   into their `*/` sibling directories, and `rag.ts` is the natural seam now that X2 has landed.
 - **Risk:** HIGH (behavioural surface). One file per PR.
@@ -198,18 +204,18 @@ collaborators join — `AGENTS.md` + the PR template already carry that load.
 
 ## Progress summary
 
-| Item                           | Priority | Status                                      |
-| ------------------------------ | -------- | ------------------------------------------- |
-| N1 Dependabot grouping         | Now      | **DONE** (#985)                             |
-| N2 Dependency-report decision  | Now      | **DONE** (#986, enabled)                    |
-| X1 Import-boundary linter      | Next     | **DONE** (#986; service-role rule dropped)  |
-| X2 `src/lib` rag extraction    | Next     | **DONE** (#994)                             |
-| X3 Monolith decomposition      | Next     | IN PROGRESS (rag #997; DocumentViewer done) |
-| X4 SAST-blocking on parser     | Next     | **DONE** (gate + policy check)              |
-| X5 ACL-migration consolidation | Next     | PROVIDER-GATED (DB owner)                   |
-| X6 Coverage floors             | Next     | OPEN                                        |
-| L1 Archive one-shot scripts    | Later    | OPEN (index shipped)                        |
-| L2 Action-SHA uniformity       | Later    | **DONE** (#992)                             |
-| L3 Single gate manifest        | Later    | **DONE** (#1002)                            |
-| L4 Ledger rotation             | Later    | OPEN                                        |
-| L5 AI map / WCAG / RPO-RTO     | Later    | **DONE / SATISFIED** (#985)                 |
+| Item                           | Priority | Status                                                  |
+| ------------------------------ | -------- | ------------------------------------------------------- |
+| N1 Dependabot grouping         | Now      | **DONE** (#985)                                         |
+| N2 Dependency-report decision  | Now      | **DONE** (#986, enabled)                                |
+| X1 Import-boundary linter      | Next     | **DONE** (#986; service-role rule dropped)              |
+| X2 `src/lib` rag extraction    | Next     | **DONE** (#994)                                         |
+| X3 Monolith decomposition      | Next     | IN PROGRESS (rag #997; DocumentViewer + Dashboard done) |
+| X4 SAST-blocking on parser     | Next     | **DONE** (gate + policy check)                          |
+| X5 ACL-migration consolidation | Next     | PROVIDER-GATED (DB owner)                               |
+| X6 Coverage floors             | Next     | OPEN                                                    |
+| L1 Archive one-shot scripts    | Later    | OPEN (index shipped)                                    |
+| L2 Action-SHA uniformity       | Later    | **DONE** (#992)                                         |
+| L3 Single gate manifest        | Later    | **DONE** (#1002)                                        |
+| L4 Ledger rotation             | Later    | OPEN                                                    |
+| L5 AI map / WCAG / RPO-RTO     | Later    | **DONE / SATISFIED** (#985)                             |
@@ -2,7 +2,7 @@
 import { readFileSync } from "node:fs";
 
 const budgets = new Map([
-  ["src/components/ClinicalDashboard.tsx", 4272],
+  ["src/components/ClinicalDashboard.tsx", 4157],
   ["src/lib/rag/rag.ts", 5030],
   ["src/components/DocumentViewer.tsx", 1733],
   ["supabase/functions/indexing-v3-agent/index.ts", 2191],

@@ -5,7 +5,6 @@ import dynamic from "next/dynamic";
 import {
   CircleAlert,
   BookOpen,
-  ChevronDown,
   Clock3,
   ExternalLink,
   FileImage,
@@ -42,7 +41,6 @@ import { readLocalProjectIdentity, unsafeLocalProjectMessage } from "@/lib/local
 import { isDeployedClinicalKb } from "@/lib/deployed-app";
 import {
   appBackdrop,
-  answerSurface,
   cn,
   EmptyState,
   floatingControl,
@@ -77,12 +75,7 @@ import {
 } from "@/components/clinical-dashboard/DocumentManagerPanel";
 import { GuideDialog, GuideTrigger, UtilityDrawer } from "@/components/clinical-dashboard/dashboard-shell";
 import { sanitizeAnswerDisplayText, sanitizeDisplayText } from "@/components/clinical-dashboard/display-text";
-import {
-  isPreformattedGroundedAnswer,
-  NaturalLanguageAnswer,
-  ScopeAndGovernanceNotice,
-  UserQuestionBubble,
-} from "@/components/clinical-dashboard/answer-content";
+import { isPreformattedGroundedAnswer, ScopeAndGovernanceNotice } from "@/components/clinical-dashboard/answer-content";
 import { AnswerEmptyState, AnswerProgressStepper, AnswerSkeleton } from "@/components/clinical-dashboard/answer-status";
 import {
   type AnswerProgressUpdate,
@@ -253,6 +246,11 @@ import type { SearchScopeFilters } from "@/lib/search-scope";
 import { differentialsMobileCompareAddonSlotId, modeHomeDesktopComposerSlotId } from "@/lib/mode-home-composer";
 import { toolCatalogRecords } from "@/lib/tools-catalog";
 import { createQuoteFollowUp, type AnswerViewMode, shouldPollForUpdates } from "@/lib/ward-output";
+import {
+  type AnswerTurn,
+  maxVisiblePriorTurns,
+  PriorAnswerTurnSurface,
+} from "@/components/clinical-dashboard/answer-thread-turn";
 
 const documentPageSize = 150;
 const activeIndexingPollFallbackMs = 5_000;
@@ -335,118 +333,6 @@ type SearchResultModePayload =
 
 type SourceLibrarySearchMode = Extract<AppModeSearchKind, "documents" | "differentials">;
 
-/**
- * A completed Q&A exchange kept on screen after a newer answer arrives, so
- * Answer mode reads as a conversation thread instead of replacing each result.
- */
-type AnswerTurn = {
-  id: string;
-  query: string;
-  answer: RagAnswer;
-  sources: SearchResult[];
-};
-
-const maxVisiblePriorTurns = 10;
-
-/**
- * Renders a collapsible, read-only view of a previous answer-thread turn with its question, answer, sources, and source-review notice.
- *
- * @param turn - The previous question and answer turn to display
- * @param copied - Whether the turn's answer has been copied
- * @param collapsed - Whether the answer content is collapsed
- * @param onToggleCollapsed - Called when the answer visibility is toggled
- * @param onCopy - Called with the answer text when copying is requested
- */
-function PriorAnswerTurnSurface({
-  turn,
-  copied,
-  collapsed,
-  onToggleCollapsed,
-  onCopy,
-}: {
-  turn: AnswerTurn;
-  copied: boolean;
-  collapsed: boolean;
-  onToggleCollapsed: () => void;
-  onCopy: (text: string) => void;
-}) {
-  const renderModel = useMemo(
-    () => buildAnswerRenderModel(turn.answer, { sources: turn.sources }),
-    [turn.answer, turn.sources],
-  );
-  const turnPreformatted = isPreformattedGroundedAnswer(turn.answer);
-  const safeText = useMemo(
-    () => sanitizeAnswerDisplayText(turn.answer.answer, { preformatted: turnPreformatted }),
-    [turn.answer.answer, turnPreformatted],
-  );
-  const sourceCount =
-    renderModel.primarySources.length ||
-    turn.sources.length ||
-    turn.answer.sources?.length ||
-    turn.answer.citations.length;
-  const previewText = safeText || turn.answer.answer;
-  const needsSourceReview =
-    turn.answer.answerQualityTier === "source_only" ||
-    turn.answer.grounded === false ||
-    renderModel.trust === "low" ||
-    renderModel.trust === "unsupported";
-
-  return (
-    <div
-      // Historical conversation turns grow unbounded and most are collapsed and
-      // scrolled off-screen; content-auto skips their layout/paint until near the
-      // viewport. Safe here — the surface has no overflowing popovers, and the
-      // expand toggle is only reachable once the turn is scrolled into view.
-      className="content-auto min-w-0 space-y-4 sm:space-y-5"
-      data-dashboard-stage="answer-thread-turn"
-      data-collapsed={collapsed ? "true" : "false"}
-    >
-      <div className={cn(answerSurface, "space-y-3 p-2.5 sm:p-3")}>
-        <UserQuestionBubble query={turn.query} />
-        <button
-          type="button"
-          onClick={onToggleCollapsed}
-          aria-expanded={!collapsed}
-          className="inline-flex min-h-tap items-center gap-1.5 rounded-md px-1 text-xs font-semibold text-[color:var(--text-muted)] transition hover:text-[color:var(--text-heading)] focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-[color:var(--focus)]"
-        >
-          <ChevronDown className={cn("h-4 w-4 transition-transform", !collapsed && "rotate-180")} aria-hidden="true" />
-          {collapsed ? "Show previous answer" : "Hide previous answer"}
-        </button>
-        {collapsed ? (
-          <p className={cn("line-clamp-2 text-sm leading-6", textMuted)}>{previewText}</p>
-        ) : (
-          <>
-            <NaturalLanguageAnswer
-              text={turn.answer.answer}
-              preformatted={turnPreformatted}
-              sourceCount={sourceCount}
-              sourceOnly={turn.answer.answerQualityTier === "source_only"}
-              bestSource={renderModel.bestSource}
-              sources={renderModel.reviewSources}
-              sourceLinks={renderModel.primarySources}
-              copied={copied}
-              onCopy={() => onCopy(renderModel.copyText || previewText)}
-            />
-            {needsSourceReview ? (
-              <div
-                role="note"
-                data-testid="prior-answer-source-review"
-                className="mt-2 flex items-start gap-2 rounded-lg border border-[color:var(--warning-border)] bg-[color:var(--warning-soft)] px-3 py-2 text-xs text-[color:var(--text-muted)]"
-              >
-                <CircleAlert className="mt-0.5 h-4 w-4 shrink-0 text-[color:var(--warning)]" aria-hidden />
-                <span>
-                  <strong className="text-[color:var(--text-heading)]">Review source match.</strong> Verify cited
-                  passages before relying on this previous answer.
-                </span>
-              </div>
-            ) : null}
-          </>
-        )}
-      </div>
-    </div>
-  );
-}
-
 type LibraryHealthTarget = "documents" | "setup" | "indexing" | "failures";
 type IndexingMonitorFilter = "all" | "active" | "failed";
 type UploadIndexingTab = "setup" | "upload" | "jobs" | "quality";

@@ -0,0 +1,126 @@
+// A completed Q&A exchange kept on screen after a newer answer arrives (the
+// answer-thread turn) and its collapsible read-only surface. Extracted from
+// ClinicalDashboard.tsx (maturity X3) as a pure move.
+import { useMemo } from "react";
+import { ChevronDown, CircleAlert } from "lucide-react";
+import { buildAnswerRenderModel } from "@/lib/answer-render-policy";
+import {
+  isPreformattedGroundedAnswer,
+  NaturalLanguageAnswer,
+  UserQuestionBubble,
+} from "@/components/clinical-dashboard/answer-content";
+import { sanitizeAnswerDisplayText } from "@/components/clinical-dashboard/display-text";
+import { answerSurface, cn, textMuted } from "@/components/ui-primitives";
+import type { RagAnswer, SearchResult } from "@/lib/types";
+
+/**
+ * A completed Q&A exchange kept on screen after a newer answer arrives, so
+ * Answer mode reads as a conversation thread instead of replacing each result.
+ */
+export type AnswerTurn = {
+  id: string;
+  query: string;
+  answer: RagAnswer;
+  sources: SearchResult[];
+};
+
+export const maxVisiblePriorTurns = 10;
+
+/**
+ * Renders a collapsible, read-only view of a previous answer-thread turn with its question, answer, sources, and source-review notice.
+ *
+ * @param turn - The previous question and answer turn to display
+ * @param copied - Whether the turn's answer has been copied
+ * @param collapsed - Whether the answer content is collapsed
+ * @param onToggleCollapsed - Called when the answer visibility is toggled
+ * @param onCopy - Called with the answer text when copying is requested
+ */
+export function PriorAnswerTurnSurface({
+  turn,
+  copied,
+  collapsed,
+  onToggleCollapsed,
+  onCopy,
+}: {
+  turn: AnswerTurn;
+  copied: boolean;
+  collapsed: boolean;
+  onToggleCollapsed: () => void;
+  onCopy: (text: string) => void;
+}) {
+  const renderModel = useMemo(
+    () => buildAnswerRenderModel(turn.answer, { sources: turn.sources }),
+    [turn.answer, turn.sources],
+  );
+  const turnPreformatted = isPreformattedGroundedAnswer(turn.answer);
+  const safeText = useMemo(
+    () => sanitizeAnswerDisplayText(turn.answer.answer, { preformatted: turnPreformatted }),
+    [turn.answer.answer, turnPreformatted],
+  );
+  const sourceCount =
+    renderModel.primarySources.length ||
+    turn.sources.length ||
+    turn.answer.sources?.length ||
+    turn.answer.citations.length;
+  const previewText = safeText || turn.answer.answer;
+  const needsSourceReview =
+    turn.answer.answerQualityTier === "source_only" ||
+    turn.answer.grounded === false ||
+    renderModel.trust === "low" ||
+    renderModel.trust === "unsupported";
+
+  return (
+    <div
+      // Historical conversation turns grow unbounded and most are collapsed and
+      // scrolled off-screen; content-auto skips their layout/paint until near the
+      // viewport. Safe here — the surface has no overflowing popovers, and the
+      // expand toggle is only reachable once the turn is scrolled into view.
+      className="content-auto min-w-0 space-y-4 sm:space-y-5"
+      data-dashboard-stage="answer-thread-turn"
+      data-collapsed={collapsed ? "true" : "false"}
+    >
+      <div className={cn(answerSurface, "space-y-3 p-2.5 sm:p-3")}>
+        <UserQuestionBubble query={turn.query} />
+        <button
+          type="button"
+          onClick={onToggleCollapsed}
+          aria-expanded={!collapsed}
+          className="inline-flex min-h-tap items-center gap-1.5 rounded-md px-1 text-xs font-semibold text-[color:var(--text-muted)] transition hover:text-[color:var(--text-heading)] focus-visible:outline focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-[color:var(--focus)]"
+        >
+          <ChevronDown className={cn("h-4 w-4 transition-transform", !collapsed && "rotate-180")} aria-hidden="true" />
+          {collapsed ? "Show previous answer" : "Hide previous answer"}
+        </button>
+        {collapsed ? (
+          <p className={cn("line-clamp-2 text-sm leading-6", textMuted)}>{previewText}</p>
+        ) : (
+          <>
+            <NaturalLanguageAnswer
+              text={turn.answer.answer}
+              preformatted={turnPreformatted}
+              sourceCount={sourceCount}
+              sourceOnly={turn.answer.answerQualityTier === "source_only"}
+              bestSource={renderModel.bestSource}
+              sources={renderModel.reviewSources}
+              sourceLinks={renderModel.primarySources}
+              copied={copied}
+              onCopy={() => onCopy(renderModel.copyText || previewText)}
+            />
+            {needsSourceReview ? (
+              <div
+                role="note"
+                data-testid="prior-answer-source-review"
+                className="mt-2 flex items-start gap-2 rounded-lg border border-[color:var(--warning-border)] bg-[color:var(--warning-soft)] px-3 py-2 text-xs text-[color:var(--text-muted)]"
+              >
+                <CircleAlert className="mt-0.5 h-4 w-4 shrink-0 text-[color:var(--warning)]" aria-hidden />
+                <span>
+                  <strong className="text-[color:var(--text-heading)]">Review source match.</strong> Verify cited
+                  passages before relying on this previous answer.
+                </span>
+              </div>
+            ) : null}
+          </>
+        )}
+      </div>
+    </div>
+  );
+}