diff --git a/src/components/insights/coach-panel/__tests__/coach-input.test.tsx b/src/components/insights/coach-panel/__tests__/coach-input.test.tsx
new file mode 100644
index 000000000..d6d05d8b8
--- /dev/null
+++ b/src/components/insights/coach-panel/__tests__/coach-input.test.tsx
@@ -0,0 +1,138 @@
+import { describe, it, expect, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+import { I18nProvider } from "@/lib/i18n/context";
+import { CoachInput } from "../coach-input";
+
+function render(node: React.ReactNode, locale: "en" | "de" = "en") {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale={locale}>{node}</I18nProvider>,
+  );
+}
+
+describe("<CoachInput>", () => {
+  it("mounts the textarea, mic, send button, and disclaimer slots", () => {
+    const html = render(
+      <CoachInput value="" onChange={() => {}} onSubmit={() => {}} />,
+    );
+    expect(html).toContain('data-slot="coach-input"');
+    expect(html).toContain('data-slot="coach-input-textarea"');
+    expect(html).toContain('data-slot="coach-input-mic"');
+    expect(html).toContain('data-slot="coach-input-send"');
+    expect(html).toContain('data-slot="coach-input-disclaimer"');
+    expect(html).toContain("Coach replies are generated");
+  });
+
+  it("renders the localised placeholder + hint", () => {
+    const html = render(
+      <CoachInput value="" onChange={() => {}} onSubmit={() => {}} />,
+    );
+    expect(html).toContain("Ask anything about your data");
+    expect(html).toContain("Press Enter to send");
+  });
+
+  it("renders the German placeholder + disclaimer when locale is 'de'", () => {
+    const html = render(
+      <CoachInput value="" onChange={() => {}} onSubmit={() => {}} />,
+      "de",
+    );
+    expect(html).toContain("Frag mich etwas zu deinen Daten");
+    expect(html).toContain("Klinische Entscheidungen gehören in die Hand");
+  });
+
+  it("disables the mic button with the v1.5 tooltip text", () => {
+    const html = render(
+      <CoachInput value="" onChange={() => {}} onSubmit={() => {}} />,
+    );
+    // The button carries both the disabled attribute and the
+    // localised v1.5 voice tooltip on aria-label. Attribute order is
+    // not guaranteed across React versions, so we check for both
+    // independently inside the same tag.
+    const micTag = html.match(
+      /<button[^>]*data-slot="coach-input-mic"[^>]*>/,
+    );
+    expect(micTag).not.toBeNull();
+    expect(micTag?.[0]).toContain("disabled");
+    expect(micTag?.[0]).toContain(
+      'aria-label="Voice input arrives with the iOS app in v1.5."',
+    );
+  });
+
+  it("disables the send button when the value is empty", () => {
+    const html = render(
+      <CoachInput value="" onChange={() => {}} onSubmit={() => {}} />,
+    );
+    const sendTag = html.match(
+      /<button[^>]*data-slot="coach-input-send"[^>]*>/,
+    );
+    expect(sendTag?.[0]).toMatch(/\sdisabled(=""|\s|>)/);
+  });
+
+  it("disables the send button when value is whitespace-only", () => {
+    const html = render(
+      <CoachInput value="   " onChange={() => {}} onSubmit={() => {}} />,
+    );
+    const sendTag = html.match(
+      /<button[^>]*data-slot="coach-input-send"[^>]*>/,
+    );
+    expect(sendTag?.[0]).toMatch(/\sdisabled(=""|\s|>)/);
+  });
+
+  it("enables the send button when there is non-empty content", () => {
+    const html = render(
+      <CoachInput
+        value="Why was BP higher on Monday?"
+        onChange={() => {}}
+        onSubmit={() => {}}
+      />,
+    );
+    // Locate the send button tag and assert no boolean `disabled=""`
+    // attribute (Tailwind class names contain the word `disabled` in
+    // utilities like `disabled:opacity-50`, so we match the actual
+    // attribute form `disabled=""` that React emits for boolean
+    // attributes).
+    const sendTag = html.match(
+      /<button[^>]*data-slot="coach-input-send"[^>]*>/,
+    );
+    expect(sendTag).not.toBeNull();
+    expect(sendTag?.[0]).not.toMatch(/\sdisabled(=""|\s|>)/);
+  });
+
+  it("disables the send button while streaming", () => {
+    const html = render(
+      <CoachInput
+        value="Hello"
+        onChange={() => {}}
+        onSubmit={() => {}}
+        disabled
+        isStreaming
+      />,
+    );
+    const sendTag = html.match(
+      /<button[^>]*data-slot="coach-input-send"[^>]*>/,
+    );
+    expect(sendTag?.[0]).toMatch(/\sdisabled(=""|\s|>)/);
+    // Spinner replaces the send icon in the streaming state.
+    expect(html).toContain("animate-spin");
+  });
+
+  it("invokes onChange when the parent passes a controlled handler", () => {
+    // SSR can't fire DOM events; smoke-check the contract by calling
+    // the supplied handler directly.
+    const handler = vi.fn();
+    render(
+      <CoachInput value="" onChange={handler} onSubmit={() => {}} />,
+    );
+    handler("typed");
+    expect(handler).toHaveBeenCalledWith("typed");
+  });
+
+  it("renders the textarea with rows=2 to match the artboard", () => {
+    const html = render(
+      <CoachInput value="" onChange={() => {}} onSubmit={() => {}} />,
+    );
+    expect(html).toMatch(
+      /data-slot="coach-input-textarea"[^>]*rows="2"/,
+    );
+  });
+});
diff --git a/src/components/insights/coach-panel/__tests__/history-rail.test.tsx b/src/components/insights/coach-panel/__tests__/history-rail.test.tsx
new file mode 100644
index 000000000..3c099534c
--- /dev/null
+++ b/src/components/insights/coach-panel/__tests__/history-rail.test.tsx
@@ -0,0 +1,136 @@
+import { describe, it, expect } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+
+import { I18nProvider } from "@/lib/i18n/context";
+import { HistoryRail } from "../history-rail";
+import type { CoachConversationsPage } from "@/lib/ai/coach/types";
+
+/**
+ * v1.4.20 phase B2b — history-rail render snapshot.
+ *
+ * The rail mounts a TanStack Query subscription so we have to wrap it
+ * in a `<QueryClientProvider>`. We seed the cache with a synthetic
+ * conversations page so the rail renders the populated state in one
+ * pass — server-side rendering doesn't drive a real network call.
+ */
+
+function makeClientWithConversations(page: CoachConversationsPage) {
+  const client = new QueryClient({
+    defaultOptions: { queries: { retry: false } },
+  });
+  client.setQueryData(["coachConversations"], page);
+  return client;
+}
+
+function render(node: React.ReactNode, client: QueryClient, locale: "en" | "de" = "en") {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale={locale}>
+      <QueryClientProvider client={client}>{node}</QueryClientProvider>
+    </I18nProvider>,
+  );
+}
+
+const samplePage: CoachConversationsPage = {
+  conversations: [
+    {
+      id: "c1",
+      title: "Why was BP higher on Monday?",
+      createdAt: "2026-05-10T08:00:00.000Z",
+      updatedAt: "2026-05-10T08:01:00.000Z",
+      messageCount: 2,
+    },
+    {
+      id: "c2",
+      title: "Compare this week to last month",
+      createdAt: "2026-05-09T14:00:00.000Z",
+      updatedAt: "2026-05-09T14:05:00.000Z",
+      messageCount: 4,
+    },
+  ],
+  nextCursor: null,
+};
+
+describe("<HistoryRail>", () => {
+  it("renders the rail wrapper + label", () => {
+    const client = makeClientWithConversations(samplePage);
+    const html = render(
+      <HistoryRail activeId={null} onSelect={() => {}} />,
+      client,
+    );
+    expect(html).toContain('data-slot="coach-history-rail"');
+    expect(html).toContain("Conversations");
+  });
+
+  it("renders one row per conversation", () => {
+    const client = makeClientWithConversations(samplePage);
+    const html = render(
+      <HistoryRail activeId={null} onSelect={() => {}} />,
+      client,
+    );
+    const rows = html.match(/data-slot="coach-history-item"/g) ?? [];
+    expect(rows.length).toBe(2);
+    expect(html).toContain("Why was BP higher on Monday?");
+    expect(html).toContain("Compare this week to last month");
+  });
+
+  it("flags the active row via data-active", () => {
+    const client = makeClientWithConversations(samplePage);
+    const html = render(
+      <HistoryRail activeId="c2" onSelect={() => {}} />,
+      client,
+    );
+    // c2 is active and gets the data-active flag.
+    expect(html).toMatch(
+      /data-slot="coach-history-item" data-active="true"/,
+    );
+  });
+
+  it("renders the empty-state copy when no conversations are cached", () => {
+    const client = makeClientWithConversations({
+      conversations: [],
+      nextCursor: null,
+    });
+    const html = render(
+      <HistoryRail activeId={null} onSelect={() => {}} />,
+      client,
+    );
+    expect(html).toContain('data-slot="coach-history-empty"');
+    expect(html).toContain("Your conversations will appear here.");
+  });
+
+  it("mounts the search input with the localised placeholder", () => {
+    const client = makeClientWithConversations(samplePage);
+    const html = render(
+      <HistoryRail activeId={null} onSelect={() => {}} />,
+      client,
+    );
+    expect(html).toMatch(
+      /data-slot="coach-history-search"[^>]*placeholder="Search conversations…"/,
+    );
+  });
+
+  it("uses German strings when locale is 'de'", () => {
+    const client = makeClientWithConversations({
+      conversations: [],
+      nextCursor: null,
+    });
+    const html = render(
+      <HistoryRail activeId={null} onSelect={() => {}} />,
+      client,
+      "de",
+    );
+    expect(html).toContain("Unterhaltungen");
+    expect(html).toContain("Deine Unterhaltungen erscheinen hier");
+  });
+
+  it("renders the delete button for each conversation row", () => {
+    const client = makeClientWithConversations(samplePage);
+    const html = render(
+      <HistoryRail activeId={null} onSelect={() => {}} />,
+      client,
+    );
+    const buttons = html.match(/data-slot="coach-history-delete"/g) ?? [];
+    expect(buttons.length).toBe(2);
+  });
+});
diff --git a/src/components/insights/coach-panel/__tests__/sources-rail.test.tsx b/src/components/insights/coach-panel/__tests__/sources-rail.test.tsx
new file mode 100644
index 000000000..522282074
--- /dev/null
+++ b/src/components/insights/coach-panel/__tests__/sources-rail.test.tsx
@@ -0,0 +1,53 @@
+import { describe, it, expect } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+import { I18nProvider } from "@/lib/i18n/context";
+import { SourcesRail } from "../sources-rail";
+
+function render(node: React.ReactNode, locale: "en" | "de" = "en") {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale={locale}>{node}</I18nProvider>,
+  );
+}
+
+describe("<SourcesRail>", () => {
+  it("renders the rail wrapper + label", () => {
+    const html = render(<SourcesRail />);
+    expect(html).toContain('data-slot="coach-sources-rail"');
+    expect(html).toContain("What I can see");
+  });
+
+  it("lists exactly five rows (BP, weight, pulse, mood, compliance)", () => {
+    const html = render(<SourcesRail />);
+    const rows = html.match(/data-slot="coach-sources-row"/g) ?? [];
+    expect(rows.length).toBe(5);
+    expect(html).toContain('data-source="bp"');
+    expect(html).toContain('data-source="weight"');
+    expect(html).toContain('data-source="pulse"');
+    expect(html).toContain('data-source="mood"');
+    expect(html).toContain('data-source="compliance"');
+  });
+
+  it("renders the localised metric labels in English", () => {
+    const html = render(<SourcesRail />);
+    expect(html).toContain("Blood pressure");
+    expect(html).toContain("Weight");
+    expect(html).toContain("Pulse");
+    expect(html).toContain("Mood");
+    expect(html).toContain("Compliance");
+  });
+
+  it("renders the German labels when locale is 'de'", () => {
+    const html = render(<SourcesRail />, "de");
+    expect(html).toContain("Blutdruck");
+    expect(html).toContain("Gewicht");
+    expect(html).toContain("Einnahmetreue");
+  });
+
+  it("renders the footer disclaimer", () => {
+    const html = render(<SourcesRail />);
+    expect(html).toContain(
+      "The Coach reads only the data you&#x27;ve connected.",
+    );
+  });
+});
diff --git a/src/components/insights/coach-panel/coach-drawer.tsx b/src/components/insights/coach-panel/coach-drawer.tsx
index 0e41e91aa..f79824d8a 100644
--- a/src/components/insights/coach-panel/coach-drawer.tsx
+++ b/src/components/insights/coach-panel/coach-drawer.tsx
@@ -15,7 +15,10 @@ import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from "@/comp
 import { cn } from "@/lib/utils";
 import { useTranslations } from "@/lib/i18n/context";
 
+import { CoachInput } from "./coach-input";
+import { HistoryRail } from "./history-rail";
 import { MessageThread } from "./message-thread";
+import { SourcesRail } from "./sources-rail";
 import {
   useCoachConversation,
   useSendCoachMessage,
@@ -193,7 +196,12 @@ export function CoachDrawer({
             data-slot="coach-drawer-history"
             className="border-border/70 hidden h-full min-h-0 border-r lg:flex lg:flex-col"
           >
-            {historyRail ?? <div className="p-3" />}
+            {historyRail ?? (
+              <HistoryRail
+                activeId={currentConversationId}
+                onSelect={(id) => setCurrentConversationId(id)}
+              />
+            )}
           </aside>
 
           {/* Centre — message thread. */}
@@ -213,11 +221,12 @@ export function CoachDrawer({
               className="border-border/70 border-t p-3 sm:p-4"
             >
               {composer ?? (
-                <FallbackComposer
+                <CoachInput
                   value={inputValue}
                   onChange={setInputValue}
                   onSubmit={() => handleSubmit(inputValue)}
                   disabled={send.isStreaming}
+                  isStreaming={send.isStreaming}
                 />
               )}
             </div>
@@ -228,7 +237,7 @@ export function CoachDrawer({
             data-slot="coach-drawer-sources"
             className="border-border/70 hidden h-full min-h-0 border-l lg:flex lg:flex-col"
           >
-            {sourcesRail ?? <div className="p-3" />}
+            {sourcesRail ?? <SourcesRail />}
           </aside>
         </div>
       </SheetContent>
@@ -236,46 +245,3 @@ export function CoachDrawer({
   );
 }
 
-/**
- * Minimal composer used until commit 3 wires the full `<CoachInput>`.
- * Kept here so the drawer is functional in isolation (storybook /
- * narrow-scope tests) without depending on the richer composer.
- */
-function FallbackComposer({
-  value,
-  onChange,
-  onSubmit,
-  disabled,
-}: {
-  value: string;
-  onChange: (next: string) => void;
-  onSubmit: () => void;
-  disabled?: boolean;
-}) {
-  const { t } = useTranslations();
-  return (
-    <form
-      onSubmit={(e) => {
-        e.preventDefault();
-        onSubmit();
-      }}
-      className="flex gap-2"
-    >
-      <input
-        type="text"
-        value={value}
-        onChange={(e) => onChange(e.target.value)}
-        placeholder={t("insights.coach.composerPlaceholder")}
-        disabled={disabled}
-        className={cn(
-          "border-border/60 bg-muted/40 text-foreground flex-1 rounded-md border",
-          "px-3 py-2 text-sm focus-visible:outline-none focus-visible:ring-2",
-          "focus-visible:ring-dracula-purple/50 disabled:opacity-60",
-        )}
-      />
-      <Button type="submit" disabled={disabled || !value.trim()} size="sm">
-        {t("insights.coach.send")}
-      </Button>
-    </form>
-  );
-}
diff --git a/src/components/insights/coach-panel/coach-input.tsx b/src/components/insights/coach-panel/coach-input.tsx
new file mode 100644
index 000000000..205c116af
--- /dev/null
+++ b/src/components/insights/coach-panel/coach-input.tsx
@@ -0,0 +1,162 @@
+"use client";
+
+import { type FormEvent, type KeyboardEvent, useCallback } from "react";
+import { Loader2, Mic, Send } from "lucide-react";
+
+import { Button } from "@/components/ui/button";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+import { cn } from "@/lib/utils";
+import { useTranslations } from "@/lib/i18n/context";
+
+/**
+ * v1.4.20 phase B2b — Coach composer.
+ *
+ * `<textarea>` wrapped in a Dracula-styled card with a send button +
+ * mic placeholder. Submit fires on:
+ *   - Enter (no Shift) → send
+ *   - Cmd/Ctrl + Enter → send (parity with the artboard ⌘↵ chip)
+ *   - Shift + Enter → newline (default browser behaviour)
+ *
+ * The composer is purely controlled — `value` + `onChange` come from
+ * the drawer. `disabled` flips during a streamed reply so we never
+ * fire two requests in parallel.
+ *
+ * Mic is rendered but disabled with a tooltip ("Voice input arrives
+ * with the iOS app in v1.5") because the natural shipper of voice is
+ * the native client, not the PWA.
+ *
+ * The disclaimer below the input is a hard requirement — Coach
+ * replies are not medical advice.
+ */
+export interface CoachInputProps {
+  value: string;
+  onChange: (next: string) => void;
+  onSubmit: () => void;
+  /** Disabled while a previous reply is still streaming. */
+  disabled?: boolean;
+  /** Surfaces the streaming-in-progress affordance on the send button. */
+  isStreaming?: boolean;
+  /** Optional textarea ref so the parent can focus on drawer open. */
+  inputId?: string;
+}
+
+export function CoachInput({
+  value,
+  onChange,
+  onSubmit,
+  disabled = false,
+  isStreaming = false,
+  inputId = "coach-composer-textarea",
+}: CoachInputProps) {
+  const { t } = useTranslations();
+
+  const handleKeyDown = useCallback(
+    (event: KeyboardEvent<HTMLTextAreaElement>) => {
+      if (event.key !== "Enter") return;
+      // Shift+Enter inserts a newline.
+      if (event.shiftKey) return;
+      // Plain Enter and ⌘/Ctrl+Enter both submit.
+      event.preventDefault();
+      if (!disabled && value.trim().length > 0) {
+        onSubmit();
+      }
+    },
+    [disabled, onSubmit, value],
+  );
+
+  const handleFormSubmit = useCallback(
+    (event: FormEvent<HTMLFormElement>) => {
+      event.preventDefault();
+      if (!disabled && value.trim().length > 0) {
+        onSubmit();
+      }
+    },
+    [disabled, onSubmit, value],
+  );
+
+  const canSubmit = !disabled && value.trim().length > 0;
+
+  return (
+    <form
+      data-slot="coach-input"
+      onSubmit={handleFormSubmit}
+      className="flex flex-col gap-2"
+    >
+      <div
+        className={cn(
+          "border-border/60 bg-muted/40 group rounded-md border",
+          "p-2.5 transition-colors",
+          "focus-within:border-dracula-purple/50 focus-within:ring-dracula-purple/15 focus-within:ring-2",
+        )}
+      >
+        <textarea
+          id={inputId}
+          data-slot="coach-input-textarea"
+          value={value}
+          onChange={(e) => onChange(e.target.value)}
+          onKeyDown={handleKeyDown}
+          placeholder={t("insights.coach.composerPlaceholder")}
+          disabled={disabled}
+          rows={2}
+          className={cn(
+            "w-full resize-none bg-transparent text-sm leading-relaxed outline-none",
+            "placeholder:text-muted-foreground disabled:opacity-60",
+          )}
+        />
+        <div className="mt-1.5 flex items-center gap-2">
+          <TooltipProvider delayDuration={200}>
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  type="button"
+                  variant="ghost"
+                  size="icon"
+                  disabled
+                  aria-label={t("insights.coach.voiceComingSoon")}
+                  data-slot="coach-input-mic"
+                  className="size-8"
+                >
+                  <Mic className="size-4" aria-hidden="true" />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>
+                {t("insights.coach.voiceComingSoon")}
+              </TooltipContent>
+            </Tooltip>
+          </TooltipProvider>
+          <span
+            data-slot="coach-input-hint"
+            className="text-muted-foreground text-[11px]"
+          >
+            {t("insights.coach.composerHint")}
+          </span>
+          <Button
+            type="submit"
+            size="sm"
+            disabled={!canSubmit}
+            data-slot="coach-input-send"
+            className="ml-auto gap-1.5"
+          >
+            {isStreaming ? (
+              <Loader2 className="size-3.5 animate-spin" aria-hidden="true" />
+            ) : (
+              <Send className="size-3.5" aria-hidden="true" />
+            )}
+            <span>{t("insights.coach.send")}</span>
+          </Button>
+        </div>
+      </div>
+      <p
+        data-slot="coach-input-disclaimer"
+        className="text-muted-foreground text-[11px]"
+      >
+        {t("insights.coach.composerDisclaimer")}
+      </p>
+    </form>
+  );
+}
diff --git a/src/components/insights/coach-panel/history-rail.tsx b/src/components/insights/coach-panel/history-rail.tsx
new file mode 100644
index 000000000..9148ec1fe
--- /dev/null
+++ b/src/components/insights/coach-panel/history-rail.tsx
@@ -0,0 +1,188 @@
+"use client";
+
+import { useMemo, useState } from "react";
+import { MessagesSquare, Search, Trash2 } from "lucide-react";
+
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { cn } from "@/lib/utils";
+import { useTranslations } from "@/lib/i18n/context";
+
+import {
+  useCoachConversations,
+  useDeleteCoachConversation,
+} from "./use-coach";
+
+/**
+ * v1.4.20 phase B2b — conversation history rail.
+ *
+ * Lives in the left column of the Coach drawer on `lg+`. Renders the
+ * paginated list returned by `GET /api/insights/chat`, lets the user
+ * filter by title (substring match), select one to resume, and delete
+ * with a confirm-then-go flow.
+ *
+ * Selection / activeId is a controlled prop so the drawer owns the
+ * authoritative state across the message thread + composer.
+ *
+ * Empty + loading + error states are all rendered inline — the rail
+ * never collapses to "0 px" so the layout stays predictable.
+ */
+export interface HistoryRailProps {
+  activeId: string | null;
+  onSelect: (id: string) => void;
+  /**
+   * Optional className passthrough so the parent can override the
+   * default layout (currently the drawer wraps it in an `<aside>`).
+   */
+  className?: string;
+}
+
+function formatRelativeTime(
+  iso: string,
+  t: (key: string, params?: Record<string, string | number>) => string,
+): string {
+  const target = new Date(iso).getTime();
+  if (Number.isNaN(target)) return "";
+  const diffMs = Date.now() - target;
+  if (diffMs < 60_000) return t("insights.relativeJustNow");
+  const minutes = Math.floor(diffMs / 60_000);
+  if (minutes < 60) return t("insights.relativeMinutesAgo", { count: minutes });
+  const hours = Math.floor(minutes / 60);
+  if (hours < 24) return t("insights.relativeHoursAgo", { count: hours });
+  const days = Math.floor(hours / 24);
+  return t("insights.relativeDaysAgo", { count: days });
+}
+
+export function HistoryRail({
+  activeId,
+  onSelect,
+  className,
+}: HistoryRailProps) {
+  const { t } = useTranslations();
+  const { conversations, isLoading } = useCoachConversations();
+  const deleteMutation = useDeleteCoachConversation();
+  const [filter, setFilter] = useState<string>("");
+  const [confirmId, setConfirmId] = useState<string | null>(null);
+
+  const filtered = useMemo(() => {
+    const q = filter.trim().toLowerCase();
+    if (!q) return conversations;
+    return conversations.filter((c) => c.title.toLowerCase().includes(q));
+  }, [conversations, filter]);
+
+  function handleDeleteRequest(id: string) {
+    if (confirmId === id) {
+      deleteMutation.mutate(id);
+      setConfirmId(null);
+      // If the user just deleted the active thread, the drawer is
+      // listening to `onSelect` for navigation; we leave it to the
+      // parent to clear `activeId` when the conversation disappears.
+    } else {
+      setConfirmId(id);
+    }
+  }
+
+  return (
+    <div
+      data-slot="coach-history-rail"
+      className={cn("flex h-full min-h-0 flex-col gap-2 p-3", className)}
+    >
+      <div className="flex items-center gap-1.5 px-1">
+        <MessagesSquare
+          className="text-muted-foreground size-3.5"
+          aria-hidden="true"
+        />
+        <span className="text-muted-foreground text-[11px] font-medium tracking-wide uppercase">
+          {t("insights.coach.historyTitle")}
+        </span>
+      </div>
+      <div className="relative">
+        <Search
+          aria-hidden="true"
+          className="text-muted-foreground pointer-events-none absolute top-1/2 left-2.5 size-3.5 -translate-y-1/2"
+        />
+        <Input
+          type="search"
+          value={filter}
+          onChange={(e) => setFilter(e.target.value)}
+          placeholder={t("insights.coach.historySearchPlaceholder")}
+          data-slot="coach-history-search"
+          className="h-8 pl-7 text-xs"
+        />
+      </div>
+      <div
+        data-slot="coach-history-list"
+        className="-mx-1 flex min-h-0 flex-1 flex-col gap-0.5 overflow-y-auto px-1"
+      >
+        {isLoading && conversations.length === 0 ? (
+          <p
+            data-slot="coach-history-loading"
+            className="text-muted-foreground px-2 py-3 text-xs"
+          >
+            {t("common.loading")}
+          </p>
+        ) : filtered.length === 0 ? (
+          <p
+            data-slot="coach-history-empty"
+            className="text-muted-foreground px-2 py-3 text-xs leading-relaxed"
+          >
+            {t("insights.coach.historyEmpty")}
+          </p>
+        ) : (
+          filtered.map((c) => {
+            const isActive = c.id === activeId;
+            const isConfirming = confirmId === c.id;
+            return (
+              <div
+                key={c.id}
+                data-slot="coach-history-item"
+                data-active={isActive ? "true" : undefined}
+                className={cn(
+                  "group flex items-center gap-1.5 rounded-md px-2 py-1.5",
+                  "text-xs transition-colors",
+                  isActive
+                    ? "bg-dracula-purple/15 text-foreground"
+                    : "text-muted-foreground hover:bg-muted/40 hover:text-foreground",
+                )}
+              >
+                <button
+                  type="button"
+                  onClick={() => onSelect(c.id)}
+                  className="min-w-0 flex-1 truncate text-left"
+                  data-slot="coach-history-select"
+                >
+                  <span className="block truncate font-medium">
+                    {c.title}
+                  </span>
+                  <span className="text-muted-foreground block text-[10px]">
+                    {formatRelativeTime(c.updatedAt, t)}
+                  </span>
+                </button>
+                <Button
+                  type="button"
+                  variant="ghost"
+                  size="icon"
+                  onClick={() => handleDeleteRequest(c.id)}
+                  aria-label={
+                    isConfirming
+                      ? t("insights.coach.historyDeleteConfirm")
+                      : t("insights.coach.historyDeleteAria")
+                  }
+                  data-slot="coach-history-delete"
+                  data-confirming={isConfirming ? "true" : undefined}
+                  className={cn(
+                    "size-6 shrink-0 opacity-0 transition-opacity group-hover:opacity-100",
+                    isConfirming &&
+                      "text-dracula-red hover:text-dracula-red opacity-100",
+                  )}
+                >
+                  <Trash2 className="size-3.5" aria-hidden="true" />
+                </Button>
+              </div>
+            );
+          })
+        )}
+      </div>
+    </div>
+  );
+}
diff --git a/src/components/insights/coach-panel/sources-rail.tsx b/src/components/insights/coach-panel/sources-rail.tsx
new file mode 100644
index 000000000..20bbaa090
--- /dev/null
+++ b/src/components/insights/coach-panel/sources-rail.tsx
@@ -0,0 +1,121 @@
+"use client";
+
+import { Activity, Eye, Heart, HeartPulse, Pill, Scale, Smile } from "lucide-react";
+
+import { cn } from "@/lib/utils";
+import { useTranslations } from "@/lib/i18n/context";
+
+/**
+ * v1.4.20 phase B2b — "What I can see" rail.
+ *
+ * Right-column companion in the Coach drawer. Lists the data sources
+ * the assistant draws on so the user can build trust in the
+ * provenance. v1.4.20 ships with a hard-coded list keyed off the
+ * five contracts the snapshot helper currently surfaces (BP, weight,
+ * pulse, mood, medication compliance). v1.4.21 will plug in fresh /
+ * stale dot indicators by reusing `<IntegrationStatusPill>`.
+ *
+ * Hardcoding the list here is deliberate: every line is i18n-driven
+ * so locale switching works out of the box, and the underlying user
+ * data is already gated behind the page-level `requireAuth()` so a
+ * user without a connected source still sees the legend.
+ */
+export interface SourcesRailProps {
+  className?: string;
+}
+
+interface SourceRow {
+  key: string;
+  metricKey: string;
+  Icon: React.ComponentType<{ className?: string }>;
+  accentClass: string;
+}
+
+const ROWS: SourceRow[] = [
+  {
+    key: "bp",
+    metricKey: "insights.coach.metric.bp",
+    Icon: HeartPulse,
+    accentClass: "text-dracula-purple",
+  },
+  {
+    key: "weight",
+    metricKey: "insights.coach.metric.weight",
+    Icon: Scale,
+    accentClass: "text-dracula-cyan",
+  },
+  {
+    key: "pulse",
+    metricKey: "insights.coach.metric.pulse",
+    Icon: Heart,
+    accentClass: "text-dracula-pink",
+  },
+  {
+    key: "mood",
+    metricKey: "insights.coach.metric.mood",
+    Icon: Smile,
+    accentClass: "text-dracula-green",
+  },
+  {
+    key: "compliance",
+    metricKey: "insights.coach.metric.compliance",
+    Icon: Pill,
+    accentClass: "text-dracula-orange",
+  },
+];
+
+export function SourcesRail({ className }: SourcesRailProps) {
+  const { t } = useTranslations();
+  return (
+    <div
+      data-slot="coach-sources-rail"
+      className={cn("flex h-full min-h-0 flex-col gap-3 p-3", className)}
+    >
+      <div className="flex items-center gap-1.5 px-1">
+        <Eye
+          className="text-muted-foreground size-3.5"
+          aria-hidden="true"
+        />
+        <span className="text-muted-foreground text-[11px] font-medium tracking-wide uppercase">
+          {t("insights.coach.sourcesTitle")}
+        </span>
+      </div>
+      <ul
+        data-slot="coach-sources-list"
+        className="flex flex-1 flex-col gap-1.5"
+      >
+        {ROWS.map((row) => (
+          <li
+            key={row.key}
+            data-slot="coach-sources-row"
+            data-source={row.key}
+            className={cn(
+              "border-border/60 bg-muted/30 flex items-center gap-2",
+              "rounded-md border px-2.5 py-2",
+            )}
+          >
+            <row.Icon className={cn("size-3.5", row.accentClass)} aria-hidden="true" />
+            <span className="text-foreground flex-1 text-xs font-medium">
+              {t(row.metricKey)}
+            </span>
+            {/* Fresh / stale indicator — v1.4.20 is a static dot.
+                v1.4.21 will reuse <IntegrationStatusPill>. */}
+            <span
+              aria-label={t("insights.coach.sourcesFresh")}
+              className="bg-dracula-green size-1.5 rounded-full"
+            />
+          </li>
+        ))}
+      </ul>
+      <div className="border-border/50 mt-auto flex items-start gap-2 border-t pt-3">
+        <Activity
+          aria-hidden="true"
+          className="text-muted-foreground mt-0.5 size-3.5 shrink-0"
+        />
+        <p className="text-muted-foreground text-[11px] leading-relaxed">
+          {t("insights.coach.sourcesFooter")}
+        </p>
+      </div>
+    </div>
+  );
+}