diff --git a/src/modules/workbench-shell/model/composer-commands.test.ts b/src/modules/workbench-shell/model/composer-commands.test.ts
index 5b9a14fe..5ce79982 100644
--- a/src/modules/workbench-shell/model/composer-commands.test.ts
+++ b/src/modules/workbench-shell/model/composer-commands.test.ts
@@ -1,6 +1,5 @@
 import { describe, expect, it } from "vitest";
 import type { PromptInputMessage } from "@/components/ai-elements/prompt-input";
-import type { RunMode } from "@/shared/types/api";
 import {
   buildCommandEffectivePrompt,
   buildComposerCommandRegistry,
@@ -10,8 +9,6 @@ import {
   parseSlashCommandInput,
 } from "@/modules/workbench-shell/model/composer-commands";
 
-const RUN_MODE: RunMode = "default";
-
 function createMessage(text: string): PromptInputMessage {
   return {
     text,
@@ -22,7 +19,7 @@ function createMessage(text: string): PromptInputMessage {
 describe("buildComposerSubmission", () => {
   it("preserves plain multi-line Markdown exactly", () => {
     const text = "  1. First\n2. Second\n\n- Bullet\n```ts\nconst value = 1;\n```\n  ";
-    const submission = buildComposerSubmission(createMessage(text), [], RUN_MODE);
+    const submission = buildComposerSubmission(createMessage(text), []);
 
     expect(submission).not.toBeNull();
     expect(submission?.kind).toBe("plain");
@@ -31,7 +28,7 @@ describe("buildComposerSubmission", () => {
   });
 
   it("rejects whitespace-only messages without attachments", () => {
-    const submission = buildComposerSubmission(createMessage(" \n\t  "), [], RUN_MODE);
+    const submission = buildComposerSubmission(createMessage(" \n\t  "), []);
 
     expect(submission).toBeNull();
   });
@@ -39,7 +36,7 @@ describe("buildComposerSubmission", () => {
   it("parses slash commands from trimmed text while preserving the original display text", () => {
     const registry = buildComposerCommandRegistry([]);
     const text = "  /init  \n";
-    const submission = buildComposerSubmission(createMessage(text), registry, RUN_MODE);
+    const submission = buildComposerSubmission(createMessage(text), registry);
 
     expect(submission).not.toBeNull();
     expect(submission?.kind).toBe("command");
@@ -51,7 +48,7 @@ describe("buildComposerSubmission", () => {
   it("preserves multi-line /goal objectives as command arguments", () => {
     const registry = buildComposerCommandRegistry([]);
     const text = "/goal First goal line\nSecond goal line\n- checklist item";
-    const submission = buildComposerSubmission(createMessage(text), registry, RUN_MODE);
+    const submission = buildComposerSubmission(createMessage(text), registry);
 
     expect(submission).not.toBeNull();
     expect(submission?.kind).toBe("command");
diff --git a/src/modules/workbench-shell/model/composer-commands.ts b/src/modules/workbench-shell/model/composer-commands.ts
index 0c1c7cd8..5e5a26f1 100644
--- a/src/modules/workbench-shell/model/composer-commands.ts
+++ b/src/modules/workbench-shell/model/composer-commands.ts
@@ -1,6 +1,6 @@
 import type { PromptInputMessage } from "@/components/ai-elements/prompt-input";
 import type { CommandEntry } from "@/modules/settings-center/model/types";
-import type { MessageAttachmentDto, RunMode } from "@/shared/types/api";
+import type { MessageAttachmentDto } from "@/shared/types/api";
 
 export type ComposerReferencedFile = {
   name: string;
@@ -139,7 +139,6 @@ export type ComposerSubmission = {
   attachments: MessageAttachmentDto[];
   command?: ComposerCommandInvocation;
   metadata?: Record<string, unknown> | null;
-  runMode?: RunMode;
 };
 
 const BUILTIN_COMMANDS: ReadonlyArray<ComposerCommandDescriptor> = [
@@ -551,7 +550,6 @@ export function buildCommandEffectivePrompt(
 export function buildComposerSubmission(
   message: PromptInputMessage,
   registry: ReadonlyArray<ComposerCommandDescriptor>,
-  runMode?: RunMode,
 ): ComposerSubmission | null {
   const rawText = message.text ?? "";
   const trimmedText = rawText.trim();
@@ -574,7 +572,6 @@ export function buildComposerSubmission(
       rawMessage: message,
       attachments,
       metadata: null,
-      runMode,
     };
   }
 
@@ -605,6 +602,5 @@ export function buildComposerSubmission(
         command: invocation,
       },
     },
-    runMode,
   };
 }
diff --git a/src/modules/workbench-shell/model/composer-store.test.ts b/src/modules/workbench-shell/model/composer-store.test.ts
index d0b0ca5a..c0b805a4 100644
--- a/src/modules/workbench-shell/model/composer-store.test.ts
+++ b/src/modules/workbench-shell/model/composer-store.test.ts
@@ -2,7 +2,6 @@ import { describe, it, expect, beforeEach } from "vitest";
 import {
   composerStore,
   setNewThreadValue,
-  setNewThreadRunMode,
   setNewThreadReferencedFiles,
   setNewThreadAttachmentData,
   setDraft,
@@ -25,13 +24,6 @@ describe("composerStore", () => {
       expect(composerStore.getState().newThreadValue).toBe("hello world");
     });
 
-    it("should set new thread run mode", () => {
-      setNewThreadRunMode("plan");
-      expect(composerStore.getState().newThreadRunMode).toBe("plan");
-      setNewThreadRunMode("default");
-      expect(composerStore.getState().newThreadRunMode).toBe("default");
-    });
-
     it("should clear new thread composer", () => {
       setNewThreadValue("some value");
       setNewThreadReferencedFiles([{ name: "test.ts", path: "/test.ts", parentPath: "/" }]);
diff --git a/src/modules/workbench-shell/model/composer-store.ts b/src/modules/workbench-shell/model/composer-store.ts
index fea3cbed..c48adcd8 100644
--- a/src/modules/workbench-shell/model/composer-store.ts
+++ b/src/modules/workbench-shell/model/composer-store.ts
@@ -1,5 +1,4 @@
 import { createStore, useStore as useStoreBase, shallowEqual } from "@/shared/lib/create-store";
-import type { RunMode } from "@/shared/types/api";
 import type { ComposerReferencedFile } from "@/modules/workbench-shell/model/composer-commands";
 
 // ---------------------------------------------------------------------------
@@ -28,8 +27,6 @@ export interface ComposerStoreState {
   [key: string]: unknown;
   /** Input value for new-thread mode. */
   newThreadValue: string;
-  /** Run mode for new threads (default / plan). */
-  newThreadRunMode: RunMode;
   /** @file references for new-thread composer. */
   newThreadReferencedFiles: ComposerReferencedFile[];
   /** Serialized attachment data for new-thread composer. */
@@ -46,7 +43,6 @@ export interface ComposerStoreState {
 
 export const composerStore = createStore<ComposerStoreState>({
   newThreadValue: "",
-  newThreadRunMode: "default",
   newThreadReferencedFiles: [],
   newThreadAttachmentData: [],
   drafts: {},
@@ -67,10 +63,6 @@ export function setNewThreadValue(value: string): void {
   composerStore.setState({ newThreadValue: value });
 }
 
-export function setNewThreadRunMode(mode: RunMode): void {
-  composerStore.setState({ newThreadRunMode: mode });
-}
-
 export function setNewThreadReferencedFiles(files: ReadonlyArray<ComposerReferencedFile>): void {
   composerStore.setState({ newThreadReferencedFiles: files as ComposerReferencedFile[] });
 }
diff --git a/src/modules/workbench-shell/model/thread-store.test.ts b/src/modules/workbench-shell/model/thread-store.test.ts
index 7980ec71..24e8f3c3 100644
--- a/src/modules/workbench-shell/model/thread-store.test.ts
+++ b/src/modules/workbench-shell/model/thread-store.test.ts
@@ -42,7 +42,6 @@ function makePendingRun(overrides?: Partial<PendingThreadRun>): PendingThreadRun
     effectivePrompt: "test prompt",
     attachments: [],
     metadata: null,
-    runMode: "default",
     threadId: "thread-1",
     ...overrides,
   };
diff --git a/src/modules/workbench-shell/model/workbench-actions.test.ts b/src/modules/workbench-shell/model/workbench-actions.test.ts
index 5950c7a9..009ce0e8 100644
--- a/src/modules/workbench-shell/model/workbench-actions.test.ts
+++ b/src/modules/workbench-shell/model/workbench-actions.test.ts
@@ -387,7 +387,7 @@ describe("deleteThread", () => {
     threadStore.setState({
       activeThreadId: null,
       workspaces: [makeWorkspace("ws-1", [thread])],
-      pendingRuns: { "thread-1": { id: "run-1", prompt: "test", runMode: "auto" } as any },
+      pendingRuns: { "thread-1": { id: "run-1", prompt: "test" } as any },
     });
 
     await deleteThread("thread-1", { skipIpc: true });
@@ -461,7 +461,7 @@ describe("removeWorkspace", () => {
     threadStore.setState({
       activeThreadId: null,
       workspaces: [ws1],
-      pendingRuns: { "thread-1": { id: "run-1", prompt: "test", runMode: "auto" } as any },
+      pendingRuns: { "thread-1": { id: "run-1", prompt: "test" } as any },
     });
 
     await removeWorkspace(ws1 as any);
@@ -583,7 +583,6 @@ describe("submitNewThread", () => {
   ): NewThreadSubmission {
     return {
       value: "test prompt",
-      runMode: "default",
       effectivePrompt: "test prompt",
       ...overrides,
     };
@@ -594,7 +593,6 @@ describe("submitNewThread", () => {
       workspaces: [],
       isNewThreadMode: true,
     });
-    composerStore.setState({ newThreadRunMode: "default" });
     settingsStore.setState({ activeAgentProfileId: "default-profile" });
 
     await submitNewThread(makeSubmission({ value: "hello" }));
@@ -626,7 +624,6 @@ describe("submitNewThread", () => {
       workspaces: [workspace],
       isNewThreadMode: true,
     });
-    composerStore.setState({ newThreadRunMode: "default" });
     settingsStore.setState({ activeAgentProfileId: "default-profile" });
 
     await submitNewThread(makeSubmission({ value: "hello" }));
@@ -659,7 +656,6 @@ describe("submitNewThread", () => {
       isNewThreadMode: true,
     });
     projectStore.setState({ selectedProject: project, recentProjects: [project] });
-    composerStore.setState({ newThreadRunMode: "default" });
     settingsStore.setState({ activeAgentProfileId: "default-profile" });
 
     await submitNewThread(makeSubmission({
@@ -703,7 +699,6 @@ describe("submitNewThread", () => {
       workspaces: [workspace],
       isNewThreadMode: true,
     });
-    composerStore.setState({ newThreadRunMode: "default" });
     settingsStore.setState({ activeAgentProfileId: "default-profile" });
 
     await submitNewThread(makeSubmission({ value: "new thread" }));
diff --git a/src/modules/workbench-shell/model/workbench-actions.ts b/src/modules/workbench-shell/model/workbench-actions.ts
index da71fc2c..02f3803e 100644
--- a/src/modules/workbench-shell/model/workbench-actions.ts
+++ b/src/modules/workbench-shell/model/workbench-actions.ts
@@ -51,7 +51,7 @@ import {
   findWorkspaceByPath,
 } from "@/modules/workbench-shell/model/workspace-path-bindings";
 import type { ProjectOption, WorkspaceItem } from "@/modules/workbench-shell/model/types";
-import type { MessageAttachmentDto, RunMode, ThreadSummaryDto, WorkspaceDto } from "@/shared/types/api";
+import type { MessageAttachmentDto, ThreadSummaryDto, WorkspaceDto } from "@/shared/types/api";
 import type { LanguagePreference } from "@/app/providers/language-provider";
 import type { ComposerCommandInvocation } from "@/modules/workbench-shell/model/composer-commands";
 
@@ -61,7 +61,6 @@ import type { ComposerCommandInvocation } from "@/modules/workbench-shell/model/
 
 export interface NewThreadSubmission {
   value: string;
-  runMode: RunMode;
   displayText?: string;
   effectivePrompt: string;
   attachments?: MessageAttachmentDto[];
@@ -574,7 +573,6 @@ export async function submitNewThread(submission: NewThreadSubmission): Promise<
 
   // Re-read workspaces after async IPC to avoid stale state
   const { workspaces } = threadStore.getState();
-  const { newThreadRunMode } = composerStore.getState();
 
   // Find or match the workspace in the sidebar
   const existingWorkspace =
@@ -674,7 +672,6 @@ export async function submitNewThread(submission: NewThreadSubmission): Promise<
       attachments: (submission.attachments ?? []) as unknown as PendingThreadRun["attachments"],
       metadata: submission.metadata ?? null,
       command: submission.command,
-      runMode: submission.runMode ?? newThreadRunMode,
       threadId,
     };
     return {
@@ -717,7 +714,6 @@ export async function submitNewThread(submission: NewThreadSubmission): Promise<
   // Reset composer
   composerStore.setState({
     newThreadValue: "",
-    newThreadRunMode: "default",
     newThreadReferencedFiles: [],
     newThreadAttachmentData: [],
     error: null,
diff --git a/src/modules/workbench-shell/ui/dashboard-workbench-logic.ts b/src/modules/workbench-shell/ui/dashboard-workbench-logic.ts
index 55658cbe..9dfc20f1 100644
--- a/src/modules/workbench-shell/ui/dashboard-workbench-logic.ts
+++ b/src/modules/workbench-shell/ui/dashboard-workbench-logic.ts
@@ -1,5 +1,5 @@
 import type { LanguagePreference } from "@/app/providers/language-provider";
-import type { MessageAttachmentDto, RunMode, WorkspaceDto } from "@/shared/types/api";
+import type { MessageAttachmentDto, WorkspaceDto } from "@/shared/types/api";
 import { buildProjectOptionFromPath } from "@/modules/workbench-shell/model/helpers";
 import type {
   ProjectOption,
@@ -188,6 +188,5 @@ export type PendingThreadRun = {
   attachments: MessageAttachmentDto[];
   metadata: Record<string, unknown> | null;
   command?: import("@/modules/workbench-shell/model/composer-commands").ComposerCommandInvocation;
-  runMode: RunMode;
   threadId: string;
 };
diff --git a/src/modules/workbench-shell/ui/dashboard-workbench.tsx b/src/modules/workbench-shell/ui/dashboard-workbench.tsx
index b8129cac..f2dd227c 100644
--- a/src/modules/workbench-shell/ui/dashboard-workbench.tsx
+++ b/src/modules/workbench-shell/ui/dashboard-workbench.tsx
@@ -262,7 +262,6 @@ const drawerWidth = useStore(uiLayoutStore, (s) => s.drawerWidth);
 
   const composerValue = useStore(composerStore, (s) => s.newThreadValue);
   const composerError = useStore(composerStore, (s) => s.error);
-  const newThreadRunMode = useStore(composerStore, (s) => s.newThreadRunMode);
   const newThreadReferencedFiles = useStore(composerStore, (s) => s.newThreadReferencedFiles);
   const newThreadAttachmentData = useStore(composerStore, (s) => s.newThreadAttachmentData);
 
@@ -714,7 +713,6 @@ const drawerWidth = useStore(uiLayoutStore, (s) => s.drawerWidth);
 
     void submitNewThread({
       value: trimmedValue,
-      runMode: newThreadRunMode,
       displayText: submission.displayText,
       effectivePrompt,
       attachments: submission.attachments,
diff --git a/src/modules/workbench-shell/ui/runtime-thread-surface-state.ts b/src/modules/workbench-shell/ui/runtime-thread-surface-state.ts
index 1b862dbe..dab0e8be 100644
--- a/src/modules/workbench-shell/ui/runtime-thread-surface-state.ts
+++ b/src/modules/workbench-shell/ui/runtime-thread-surface-state.ts
@@ -7,7 +7,6 @@ import type {
   MessageAttachmentDto,
   MessageDto,
   MessagePartDto,
-  RunMode,
   RunSummaryDto,
   ThreadSnapshotDto,
   ToolCallDto,
@@ -279,7 +278,6 @@ export type InitialPromptRequest = {
   effectivePrompt: string;
   attachments: MessageAttachmentDto[];
   metadata: Record<string, unknown> | null;
-  runMode?: RunMode;
 };
 
 export type ThinkingPlaceholder = {
@@ -392,22 +390,6 @@ export function mapRecordedUserMessage(event: RecordedUserMessageEvent): Surface
 
 
 
-export function deriveSelectedRunMode(snapshot: ThreadSnapshotDto, currentMode: RunMode) {
-  if (
-    snapshot.thread.status === "waiting_approval"
-    && !snapshot.activeRun
-    && snapshot.latestRun?.runMode === "plan"
-  ) {
-    return "plan";
-  }
-
-  if (snapshot.activeRun?.runMode === "default" || snapshot.activeRun?.runMode === "plan") {
-    return snapshot.activeRun.runMode;
-  }
-
-  return currentMode;
-}
-
 export function formatApprovalPromptState(state: string, approvedAction: PlanApprovalAction | null, t: (key: TranslationKey) => string) {
   switch (state) {
     case "approved":
diff --git a/src/modules/workbench-shell/ui/runtime-thread-surface.tsx b/src/modules/workbench-shell/ui/runtime-thread-surface.tsx
index 6fbfb3e3..ef06efe8 100644
--- a/src/modules/workbench-shell/ui/runtime-thread-surface.tsx
+++ b/src/modules/workbench-shell/ui/runtime-thread-surface.tsx
@@ -38,7 +38,6 @@ import {
 } from "@/services/thread-stream";
 import type {
   MessageAttachmentDto,
-  RunMode,
   RuntimeQueueMessageKind,
   RuntimeQueueMessageDto,
   RuntimeQueueSnapshotDto,
@@ -118,7 +117,6 @@ import { TaskHistoryTimeline } from "@/modules/workbench-shell/ui/task-stage-his
 import {
   appendOrReplaceMessage,
   compareTimelineEntries,
-  deriveSelectedRunMode,
   formatApprovalPromptState,
   formatToolStatusLabel,
   getApprovalReason,
@@ -356,7 +354,6 @@ export function RuntimeThreadSurface({
     threadStore,
     (s) => (threadId ? s.threadStatuses[threadId]?.runId ?? null : null),
   );
-  const [selectedRunMode, setSelectedRunMode] = useState<RunMode>("default");
   const [snapshotReady, setSnapshotReady] = useState(false);
   const [snapshotThreadId, setSnapshotThreadId] = useState<string | null>(null);
 
@@ -376,7 +373,6 @@ export function RuntimeThreadSurface({
   useEffect(() => {
     if (prevThreadIdRef.current !== threadId) {
       prevThreadIdRef.current = threadId;
-      setSelectedRunMode("default");
       setRuntimeQueueSubmitMode(defaultAppendMessageKind);
       setRequestRetryEntries([]);
       setRequestRetryOpen({});
@@ -694,7 +690,6 @@ export function RuntimeThreadSurface({
         }
         eventBufferRef.current = [];
       }
-      setSelectedRunMode((current) => deriveSelectedRunMode(snapshot, current));
       if (!shouldPreserveContextUsage) {
         threadStore.setState({ runtimeContextUsage: nextContextUsage });
       }
@@ -836,7 +831,6 @@ export function RuntimeThreadSurface({
         errorMessage: null,
         retryCount: 0,
       });
-      setSelectedRunMode((current) => deriveSelectedRunMode(snapshot, current));
 
       const latestVisibleRun = getLatestVisibleRun(snapshot);
       if (latestVisibleRun?.id === runId) {
@@ -1017,9 +1011,6 @@ export function RuntimeThreadSurface({
 
       if (event.type === "run_started") {
         setApprovingPlanMessageId(null);
-        if (event.runMode === "default" || event.runMode === "plan") {
-          setSelectedRunMode(event.runMode);
-        }
       }
 
       if (event.type === "stream_resync_required") {
@@ -1505,7 +1496,6 @@ export function RuntimeThreadSurface({
 
   const submitPrompt = useCallback(async (
     submissionOrPrompt: ComposerSubmission | string,
-    runModeOverride?: RunMode,
   ): Promise<boolean> => {
     if (!threadId) {
       setComposerError("This thread is still preparing. Try again in a moment.");
@@ -1520,7 +1510,6 @@ export function RuntimeThreadSurface({
           rawMessage: { text: submissionOrPrompt, files: [] },
           attachments: [],
           metadata: null,
-          runMode: runModeOverride,
         }
       : submissionOrPrompt;
     const prompt = submission.effectivePrompt ?? "";
@@ -1726,7 +1715,7 @@ export function RuntimeThreadSurface({
           promptMetadata: submission.metadata ?? null,
           attachments: submission.attachments,
         },
-        runModeOverride ?? submission.runMode ?? selectedRunMode,
+        "default",
         modelPlan,
       );
     } catch (error) {
@@ -1736,7 +1725,7 @@ export function RuntimeThreadSurface({
       submittingRef.current = false;
     }
     return true;
-  }, [activeAgentProfileId, activeProfile, agentProfiles, appendOptimisticUserMessage, loadSnapshot, providers, runState, runtimeQueueSubmitMode, selectedRunMode, t, threadId]);
+  }, [activeAgentProfileId, activeProfile, agentProfiles, appendOptimisticUserMessage, loadSnapshot, providers, runState, runtimeQueueSubmitMode, t, threadId]);
 
   const cancelRuntimeQueueMessage = useCallback(async (messageId: string) => {
     if (!threadId || !streamRef.current) {
@@ -1884,9 +1873,6 @@ export function RuntimeThreadSurface({
 
     // Mark as handled at the store level — survives component unmount/remount.
     markPendingRunHandled(initialPromptRequestId!);
-    if (initialPromptRequest.runMode) {
-      setSelectedRunMode(initialPromptRequest.runMode);
-    }
     const pendingRunSubmission: ComposerSubmission = {
       kind: initialPromptRequest.command ? "command" : "plain",
       displayText: initialPromptRequest.displayText,
@@ -1895,9 +1881,8 @@ export function RuntimeThreadSurface({
       attachments: initialPromptRequest.attachments,
       command: initialPromptRequest.command,
       metadata: initialPromptRequest.metadata,
-      runMode: initialPromptRequest.runMode,
     };
-    void submitPrompt(pendingRunSubmission, initialPromptRequest.runMode)
+    void submitPrompt(pendingRunSubmission)
       .finally(() => {
         threadStore.setState((prev) => {
           const next = Object.fromEntries(
diff --git a/src/modules/workbench-shell/ui/workbench-prompt-composer.tsx b/src/modules/workbench-shell/ui/workbench-prompt-composer.tsx
index 6acd577a..25df8b42 100644
--- a/src/modules/workbench-shell/ui/workbench-prompt-composer.tsx
+++ b/src/modules/workbench-shell/ui/workbench-prompt-composer.tsx
@@ -72,7 +72,7 @@ import type { updateAgentProfile as updateAgentProfileAction } from "@/modules/s
 import { sortAgentProfilesByName } from "@/modules/settings-center/model/profile-utils";
 import { profileSubagentAccessGet } from "@/services/bridge/subagent-commands";
 import type { SkillRecord } from "@/shared/types/extensions";
-import type { RunMode, RuntimeQueueMessageKind } from "@/shared/types/api";
+import type { RuntimeQueueMessageKind } from "@/shared/types/api";
 import { indexFilterFiles, type FileFilterMatch } from "@/services/bridge";
 import type { SerializableAttachment } from "@/modules/workbench-shell/model/composer-store";
 import { useT } from "@/i18n";
@@ -182,7 +182,6 @@ function isSlashCommandActive(value: string) {
 function buildSubmissionFromPromptInput(
   message: PromptInputMessage,
   registry: ReadonlyArray<ComposerCommandDescriptor>,
-  runMode: RunMode,
   referencedFiles: ReadonlyArray<ComposerReferencedFile>,
 ): ComposerSubmission {
   const rawText = message.text ?? "";
@@ -215,7 +214,6 @@ function buildSubmissionFromPromptInput(
             },
           }
         : null,
-      runMode,
     };
   }
 
@@ -227,7 +225,6 @@ function buildSubmissionFromPromptInput(
     effectivePrompt,
     rawMessage: message,
     attachments,
-    runMode,
     command: {
       source: parsedCommand.command.source,
       name: parsedCommand.command.name,
@@ -2143,7 +2140,7 @@ export function WorkbenchPromptComposer({
   // must be called inside a PromptInput descendant.
 
   const handlePromptSubmit = async (message: PromptInputMessage) => {
-    const submission = buildSubmissionFromPromptInput(message, commandRegistry, "default", referencedFiles);
+    const submission = buildSubmissionFromPromptInput(message, commandRegistry, referencedFiles);
     await onSubmit(submission);
     // Only clear referenced files and sources after a successful submit.
     // If onSubmit throws (e.g. thread has an active run), the composer