diff --git a/frontend/components/message.tsx b/frontend/components/message.tsx
index 761c58c..15618fd 100644
--- a/frontend/components/message.tsx
+++ b/frontend/components/message.tsx
@@ -5,6 +5,7 @@ import { getToolName, isToolUIPart } from "ai";
 import equal from "fast-deep-equal";
 import Image from "next/image";
 import { memo } from "react";
+import { TOOL_PANELS } from "@/features/tool-panel-registry";
 import type { ChatMessage } from "@/lib/types";
 import { cn, sanitizeText } from "@/lib/utils";
 import { BouncingDots } from "./elements/bouncing-dots";
@@ -12,37 +13,6 @@ import { MessageContent } from "./elements/message";
 import { Response } from "./elements/response";
 import { ToolCall } from "./elements/tool-call";
 import { MessageActions } from "./message-actions";
-import { RetrievedTracksPanel } from "./retrieved-tracks-panel";
-import { SessionListPanel } from "./session-list-panel";
-import { SessionVisualization } from "./session-visualization";
-
-function extractSessionId(input: unknown): string | null {
-  if (input && typeof input === "object" && "session_id" in input) {
-    const value = (input as { session_id: unknown }).session_id;
-    if (typeof value === "string" && value.length > 0) {
-      return value;
-    }
-  }
-  return null;
-}
-
-// The list_sessions tool embeds each session's UUID in an HTML comment
-// (`<!-- id=... -->`) on its line so the agent can resolve "Session 07" → UUID
-// without leaking the UUID to the user. We extract the same comments here so
-// the rendered panel mirrors exactly what the agent decided to show — order
-// and all — instead of duplicating the tool's filter logic on the frontend.
-const SESSION_ID_COMMENT = /<!--\s*id=([0-9a-f-]+)\s*-->/gi;
-
-function extractSessionIdsFromOutput(output: unknown): string[] | null {
-  if (typeof output !== "string") {
-    return null;
-  }
-  const ids: string[] = [];
-  for (const match of output.matchAll(SESSION_ID_COMMENT)) {
-    ids.push(match[1]);
-  }
-  return ids.length > 0 ? ids : null;
-}
 
 const AssistantAvatar = ({ isLoading }: { isLoading?: boolean }) => (
   <div
@@ -129,36 +99,18 @@ const PurePreviewMessage = ({
             }
             if (isToolUIPart(part)) {
               const toolName = getToolName(part);
-              const isOutputAvailable = part.state === "output-available";
-              const analyzeSessionId =
-                toolName === "analyze_session" && isOutputAvailable
-                  ? extractSessionId(part.input)
-                  : null;
-              const retrievalSessionId =
-                toolName === "retrieve_tracks_from_brain_state" &&
-                isOutputAvailable
-                  ? extractSessionId(part.input)
-                  : null;
-              const showSessionList =
-                toolName === "list_sessions" && isOutputAvailable;
-              const sessionListIds = showSessionList
-                ? extractSessionIdsFromOutput(part.output)
-                : null;
+              const entry = TOOL_PANELS[toolName];
+              const showPanel =
+                entry != null && part.state === "output-available";
               return (
                 <div className="flex flex-col gap-2" key={key}>
                   <ToolCall
-                    hideOutput={showSessionList}
+                    hideOutput={showPanel && entry.hideRawOutput === true}
                     isStreaming={isLoading && !hasTextParts}
                     part={part}
                   />
-                  {analyzeSessionId && (
-                    <SessionVisualization sessionId={analyzeSessionId} />
-                  )}
-                  {retrievalSessionId && (
-                    <RetrievedTracksPanel sessionId={retrievalSessionId} />
-                  )}
-                  {showSessionList && (
-                    <SessionListPanel sessionIds={sessionListIds} />
+                  {showPanel && (
+                    <entry.Panel input={part.input} output={part.output} />
                   )}
                 </div>
               );
diff --git a/frontend/components/retrieved-tracks-panel.tsx b/frontend/features/retrieval/retrieved-tracks-panel.tsx
similarity index 99%
rename from frontend/components/retrieved-tracks-panel.tsx
rename to frontend/features/retrieval/retrieved-tracks-panel.tsx
index c536561..95c0be0 100644
--- a/frontend/components/retrieved-tracks-panel.tsx
+++ b/frontend/features/retrieval/retrieved-tracks-panel.tsx
@@ -10,9 +10,9 @@ import {
   TooltipProvider,
   TooltipTrigger,
 } from "@/components/ui/tooltip";
-import { WaveformViz } from "@/components/waveform-viz";
 import { BACKEND_URL } from "@/lib/constants";
 import { cn } from "@/lib/utils";
+import { WaveformViz } from "./waveform-viz";
 
 // Backend serves the cached m4a under its own CORS policy so wavesurfer can
 // fetch + decodeAudioData; Apple's preview CDN does not reliably set CORS
diff --git a/frontend/features/retrieval/tool-panels.tsx b/frontend/features/retrieval/tool-panels.tsx
new file mode 100644
index 0000000..438e494
--- /dev/null
+++ b/frontend/features/retrieval/tool-panels.tsx
@@ -0,0 +1,20 @@
+"use client";
+
+import type {
+  ToolPanelEntry,
+  ToolPanelProps,
+} from "@/features/tool-panel-registry";
+import { extractSessionId } from "@/lib/extract-session-id";
+import { RetrievedTracksPanel } from "./retrieved-tracks-panel";
+
+function RetrieveTracksPanel({ input }: ToolPanelProps) {
+  const sessionId = extractSessionId(input);
+  if (!sessionId) {
+    return null;
+  }
+  return <RetrievedTracksPanel sessionId={sessionId} />;
+}
+
+export const RETRIEVAL_TOOL_PANELS: Record<string, ToolPanelEntry> = {
+  retrieve_tracks_from_brain_state: { Panel: RetrieveTracksPanel },
+};
diff --git a/frontend/components/waveform-viz.tsx b/frontend/features/retrieval/waveform-viz.tsx
similarity index 100%
rename from frontend/components/waveform-viz.tsx
rename to frontend/features/retrieval/waveform-viz.tsx
diff --git a/frontend/components/emotion-trajectory.tsx b/frontend/features/sessions/emotion-trajectory.tsx
similarity index 100%
rename from frontend/components/emotion-trajectory.tsx
rename to frontend/features/sessions/emotion-trajectory.tsx
diff --git a/frontend/components/session-list-panel.tsx b/frontend/features/sessions/session-list-panel.tsx
similarity index 98%
rename from frontend/components/session-list-panel.tsx
rename to frontend/features/sessions/session-list-panel.tsx
index 2437e95..5831cb2 100644
--- a/frontend/components/session-list-panel.tsx
+++ b/frontend/features/sessions/session-list-panel.tsx
@@ -3,6 +3,7 @@
 import { memo } from "react";
 import type { SessionSummarySchema } from "@/api/generated/types.gen";
 import { useEnrichedSessions } from "@/api/hooks/sessions";
+import { useChatActions } from "@/components/chat-actions-provider";
 import {
   Tooltip,
   TooltipContent,
@@ -10,7 +11,6 @@ import {
   TooltipTrigger,
 } from "@/components/ui/tooltip";
 import { cn } from "@/lib/utils";
-import { useChatActions } from "./chat-actions-provider";
 
 const QUADRANT_ORDER = ["relaxed", "calm", "excited", "stressed"] as const;
 type Quadrant = (typeof QUADRANT_ORDER)[number];
diff --git a/frontend/components/session-visualization.tsx b/frontend/features/sessions/session-visualization.tsx
similarity index 99%
rename from frontend/components/session-visualization.tsx
rename to frontend/features/sessions/session-visualization.tsx
index f01a3a7..0ecc7fe 100644
--- a/frontend/components/session-visualization.tsx
+++ b/frontend/features/sessions/session-visualization.tsx
@@ -17,8 +17,8 @@ import type {
   TrajectorySummary,
 } from "@/api/generated/types.gen";
 import { useSessionSegments } from "@/api/hooks/sessions";
-import { EmotionTrajectory } from "@/components/emotion-trajectory";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
+import { EmotionTrajectory } from "./emotion-trajectory";
 
 type Props = {
   sessionId: string;
diff --git a/frontend/features/sessions/tool-panels.tsx b/frontend/features/sessions/tool-panels.tsx
new file mode 100644
index 0000000..13e8286
--- /dev/null
+++ b/frontend/features/sessions/tool-panels.tsx
@@ -0,0 +1,44 @@
+"use client";
+
+import type {
+  ToolPanelEntry,
+  ToolPanelProps,
+} from "@/features/tool-panel-registry";
+import { extractSessionId } from "@/lib/extract-session-id";
+import { SessionListPanel } from "./session-list-panel";
+import { SessionVisualization } from "./session-visualization";
+
+// The list_sessions tool embeds each session's UUID in an HTML comment
+// (`<!-- id=... -->`) on its line so the agent can resolve "Session 07" → UUID
+// without leaking the UUID to the user. We extract the same comments here so
+// the rendered panel mirrors exactly what the agent decided to show — order
+// and all — instead of duplicating the tool's filter logic on the frontend.
+const SESSION_ID_COMMENT = /<!--\s*id=([0-9a-f-]+)\s*-->/gi;
+
+function extractSessionIdsFromOutput(output: unknown): string[] | null {
+  if (typeof output !== "string") {
+    return null;
+  }
+  const ids: string[] = [];
+  for (const match of output.matchAll(SESSION_ID_COMMENT)) {
+    ids.push(match[1]);
+  }
+  return ids.length > 0 ? ids : null;
+}
+
+function AnalyzeSessionPanel({ input }: ToolPanelProps) {
+  const sessionId = extractSessionId(input);
+  if (!sessionId) {
+    return null;
+  }
+  return <SessionVisualization sessionId={sessionId} />;
+}
+
+function ListSessionsPanel({ output }: ToolPanelProps) {
+  return <SessionListPanel sessionIds={extractSessionIdsFromOutput(output)} />;
+}
+
+export const SESSIONS_TOOL_PANELS: Record<string, ToolPanelEntry> = {
+  analyze_session: { Panel: AnalyzeSessionPanel },
+  list_sessions: { Panel: ListSessionsPanel, hideRawOutput: true },
+};
diff --git a/frontend/features/tool-panel-registry.ts b/frontend/features/tool-panel-registry.ts
new file mode 100644
index 0000000..9c21a4f
--- /dev/null
+++ b/frontend/features/tool-panel-registry.ts
@@ -0,0 +1,19 @@
+import type { ComponentType } from "react";
+import { RETRIEVAL_TOOL_PANELS } from "./retrieval/tool-panels";
+import { SESSIONS_TOOL_PANELS } from "./sessions/tool-panels";
+
+export type ToolPanelProps = { input: unknown; output: unknown };
+
+export type ToolPanelEntry = {
+  Panel: ComponentType<ToolPanelProps>;
+  /** Suppress <ToolCall>'s raw output block when the panel replaces it. */
+  hideRawOutput?: boolean;
+};
+
+// Composition root: the only file that imports across feature slices.
+// Each slice exports its own tool-name -> panel map; adding a feature is
+// one spread here. message.tsx does a lookup — never per-tool branching.
+export const TOOL_PANELS: Record<string, ToolPanelEntry> = {
+  ...SESSIONS_TOOL_PANELS,
+  ...RETRIEVAL_TOOL_PANELS,
+};
diff --git a/frontend/lib/extract-session-id.ts b/frontend/lib/extract-session-id.ts
new file mode 100644
index 0000000..650e560
--- /dev/null
+++ b/frontend/lib/extract-session-id.ts
@@ -0,0 +1,9 @@
+export function extractSessionId(input: unknown): string | null {
+  if (input && typeof input === "object" && "session_id" in input) {
+    const value = (input as { session_id: unknown }).session_id;
+    if (typeof value === "string" && value.length > 0) {
+      return value;
+    }
+  }
+  return null;
+}