diff --git a/apps/web/src/components/ChatView.logic.ts b/apps/web/src/components/ChatView.logic.ts
index 1821c65ed9..e6984aed8e 100644
--- a/apps/web/src/components/ChatView.logic.ts
+++ b/apps/web/src/components/ChatView.logic.ts
@@ -1,4 +1,10 @@
-import { ProjectId, type ModelSelection, type ThreadId, type TurnId } from "@t3tools/contracts";
+import {
+  ProjectId,
+  type MessageId,
+  type ModelSelection,
+  type ThreadId,
+  type TurnId,
+} from "@t3tools/contracts";
 import { type ChatMessage, type SessionPhase, type Thread, type ThreadSession } from "../types";
 import { randomUUID } from "~/lib/utils";
 import { type ComposerImageAttachment, type DraftThreadState } from "../composerDraftStore";
@@ -11,6 +17,7 @@ import {
 } from "../lib/terminalContext";
 
 export const LAST_INVOKED_SCRIPT_BY_PROJECT_KEY = "t3code:last-invoked-script-by-project";
+export const EDIT_REVERT_SYNC_TIMEOUT_MS = 3000;
 const WORKTREE_BRANCH_PREFIX = "t3code";
 
 export const LastInvokedScriptByProjectSchema = Schema.Record(ProjectId, Schema.String);
@@ -119,6 +126,80 @@ export function cloneComposerImageForRetry(
   }
 }
 
+export function waitForThreadMessageRemoval(
+  threadId: ThreadId,
+  messageId: MessageId,
+  timeoutMs = EDIT_REVERT_SYNC_TIMEOUT_MS,
+): Promise<void> {
+  return new Promise((resolve) => {
+    const hasMessage = () =>
+      useStore
+        .getState()
+        .threads.find((thread) => thread.id === threadId)
+        ?.messages.some((message) => message.id === messageId) ?? false;
+
+    if (!hasMessage()) {
+      resolve();
+      return;
+    }
+
+    let settled = false;
+    const finish = () => {
+      if (settled) {
+        return;
+      }
+      settled = true;
+      unsubscribe();
+      globalThis.clearTimeout(timeoutId);
+      resolve();
+    };
+
+    const unsubscribe = useStore.subscribe((state) => {
+      const stillPresent =
+        state.threads
+          .find((thread) => thread.id === threadId)
+          ?.messages.some((message) => message.id === messageId) ?? false;
+      if (!stillPresent) {
+        finish();
+      }
+    });
+
+    const timeoutId = globalThis.setTimeout(() => {
+      finish();
+    }, timeoutMs);
+  });
+}
+
+export async function materializeMessageImageAttachmentForEdit(
+  attachment: Extract<NonNullable<ChatMessage["attachments"]>[number], { type: "image" }>,
+): Promise<ComposerImageAttachment | null> {
+  if (!attachment.previewUrl) {
+    return null;
+  }
+
+  try {
+    const response = await fetch(attachment.previewUrl);
+    if (!response.ok) {
+      throw new Error(`Failed to load ${attachment.name}.`);
+    }
+    const blob = await response.blob();
+    const file = new File([blob], attachment.name, {
+      type: blob.type || attachment.mimeType,
+    });
+    return {
+      type: "image",
+      id: attachment.id,
+      name: attachment.name,
+      mimeType: file.type || attachment.mimeType,
+      sizeBytes: blob.size || attachment.sizeBytes,
+      previewUrl: attachment.previewUrl,
+      file,
+    };
+  } catch {
+    return null;
+  }
+}
+
 export function deriveComposerSendState(options: {
   prompt: string;
   imageCount: number;
diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
index 76133712d4..3a8a5fcc2a 100644
--- a/apps/web/src/components/ChatView.tsx
+++ b/apps/web/src/components/ChatView.tsx
@@ -137,6 +137,7 @@ import {
 } from "../composerDraftStore";
 import {
   appendTerminalContextsToPrompt,
+  deriveDisplayedUserMessageState,
   formatTerminalContextLabel,
   insertInlineTerminalContextPlaceholder,
   removeInlineTerminalContextPlaceholder,
@@ -153,7 +154,7 @@ import {
 import { selectThreadTerminalState, useTerminalStateStore } from "../terminalStateStore";
 import { ComposerPromptEditor, type ComposerPromptEditorHandle } from "./ComposerPromptEditor";
 import { PullRequestThreadDialog } from "./PullRequestThreadDialog";
-import { MessagesTimeline } from "./chat/MessagesTimeline";
+import { MessagesTimeline, type TimelineUserChatMessage } from "./chat/MessagesTimeline";
 import { ChatHeader } from "./chat/ChatHeader";
 import { ContextWindowMeter } from "./chat/ContextWindowMeter";
 import { buildExpandedImagePreview, ExpandedImagePreview } from "./chat/ExpandedImagePreview";
@@ -188,8 +189,11 @@ import {
   readFileAsDataUrl,
   revokeBlobPreviewUrl,
   revokeUserMessagePreviewUrls,
+  EDIT_REVERT_SYNC_TIMEOUT_MS,
+  materializeMessageImageAttachmentForEdit,
   threadHasStarted,
   waitForStartedServerThread,
+  waitForThreadMessageRemoval,
 } from "./ChatView.logic";
 import { useLocalStorage } from "~/hooks/useLocalStorage";
 import {
@@ -492,6 +496,11 @@ export default function ChatView({ threadId }: ChatViewProps) {
   >({});
   const [isConnecting, _setIsConnecting] = useState(false);
   const [isRevertingCheckpoint, setIsRevertingCheckpoint] = useState(false);
+  const [editingUserMessageId, setEditingUserMessageId] = useState<MessageId | null>(null);
+  const [editingUserMessageText, setEditingUserMessageText] = useState("");
+  const [editingUserMessageImages, setEditingUserMessageImages] = useState<ComposerImageAttachment[]>(
+    [],
+  );
   const [respondingRequestIds, setRespondingRequestIds] = useState<ApprovalRequestId[]>([]);
   const [respondingUserInputRequestIds, setRespondingUserInputRequestIds] = useState<
     ApprovalRequestId[]
@@ -2525,6 +2534,74 @@ export default function ChatView({ threadId }: ChatViewProps) {
     setThreadError(activeThreadId, error);
   };
 
+  const addEditingUserMessageImages = useCallback(
+    (files: File[]) => {
+      if (!activeThreadId || files.length === 0) return;
+
+      const nextImages: ComposerImageAttachment[] = [];
+      let nextImageCount = editingUserMessageImages.length;
+      let error: string | null = null;
+      for (const file of files) {
+        if (!file.type.startsWith("image/")) {
+          error = `Unsupported file type for '${file.name}'. Please attach image files only.`;
+          continue;
+        }
+        if (file.size > PROVIDER_SEND_TURN_MAX_IMAGE_BYTES) {
+          error = `'${file.name}' exceeds the ${IMAGE_SIZE_LIMIT_LABEL} attachment limit.`;
+          continue;
+        }
+        if (nextImageCount >= PROVIDER_SEND_TURN_MAX_ATTACHMENTS) {
+          error = `You can attach up to ${PROVIDER_SEND_TURN_MAX_ATTACHMENTS} images per message.`;
+          break;
+        }
+
+        const previewUrl = URL.createObjectURL(file);
+        nextImages.push({
+          type: "image",
+          id: randomUUID(),
+          name: file.name || "image",
+          mimeType: file.type,
+          sizeBytes: file.size,
+          previewUrl,
+          file,
+        });
+        nextImageCount += 1;
+      }
+
+      if (nextImages.length > 0) {
+        setEditingUserMessageImages((existing) => [...existing, ...nextImages]);
+      }
+      setThreadError(activeThreadId, error);
+    },
+    [activeThreadId, editingUserMessageImages.length, setThreadError],
+  );
+
+  const removeEditingUserMessageImage = useCallback((imageId: string) => {
+    setEditingUserMessageImages((existing) => {
+      const image = existing.find((entry) => entry.id === imageId);
+      if (image) {
+        revokeBlobPreviewUrl(image.previewUrl);
+      }
+      return existing.filter((entry) => entry.id !== imageId);
+    });
+  }, []);
+
+  const onEditUserMessagePaste = useCallback(
+    (event: React.ClipboardEvent<HTMLTextAreaElement>) => {
+      const files = Array.from(event.clipboardData.files);
+      if (files.length === 0) {
+        return;
+      }
+      const imageFiles = files.filter((file) => file.type.startsWith("image/"));
+      if (imageFiles.length === 0) {
+        return;
+      }
+      event.preventDefault();
+      addEditingUserMessageImages(imageFiles);
+    },
+    [addEditingUserMessageImages],
+  );
+
   const removeComposerImage = (imageId: string) => {
     removeComposerImageFromDraft(imageId);
   };
@@ -2588,23 +2665,32 @@ export default function ChatView({ threadId }: ChatViewProps) {
   };
 
   const onRevertToTurnCount = useCallback(
-    async (turnCount: number) => {
+    async (
+      turnCount: number,
+      options?: {
+        confirm?: boolean;
+      },
+    ): Promise<boolean> => {
       const api = readNativeApi();
-      if (!api || !activeThread || isRevertingCheckpoint) return;
+      if (!api || !activeThread || isRevertingCheckpoint) {
+        return false;
+      }
 
       if (phase === "running" || isSendBusy || isConnecting) {
         setThreadError(activeThread.id, "Interrupt the current turn before reverting checkpoints.");
-        return;
+        return false;
       }
-      const confirmed = await api.dialogs.confirm(
-        [
-          `Revert this thread to checkpoint ${turnCount}?`,
-          "This will discard newer messages and turn diffs in this thread.",
-          "This action cannot be undone.",
-        ].join("\n"),
-      );
-      if (!confirmed) {
-        return;
+      if (options?.confirm !== false) {
+        const confirmed = await api.dialogs.confirm(
+          [
+            `Revert this thread to checkpoint ${turnCount}?`,
+            "This will discard newer messages and turn diffs in this thread.",
+            "This action cannot be undone.",
+          ].join("\n"),
+        );
+        if (!confirmed) {
+          return false;
+        }
       }
 
       setIsRevertingCheckpoint(true);
@@ -2617,80 +2703,33 @@ export default function ChatView({ threadId }: ChatViewProps) {
           turnCount,
           createdAt: new Date().toISOString(),
         });
+        return true;
       } catch (err) {
         setThreadError(
           activeThread.id,
           err instanceof Error ? err.message : "Failed to revert thread state.",
         );
+        return false;
+      } finally {
+        setIsRevertingCheckpoint(false);
       }
-      setIsRevertingCheckpoint(false);
     },
     [activeThread, isConnecting, isRevertingCheckpoint, isSendBusy, phase, setThreadError],
   );
 
-  const onSend = async (e?: { preventDefault: () => void }) => {
-    e?.preventDefault();
+  const submitComposerTurn = async (input: {
+    promptForSend: string;
+    trimmedPrompt: string;
+    composerImagesSnapshot: ComposerImageAttachment[];
+    composerTerminalContextsSnapshot: TerminalContextDraft[];
+    clearComposerDraft: boolean;
+    expiredTerminalContextCount: number;
+  }) => {
     const api = readNativeApi();
-    if (!api || !activeThread || isSendBusy || isConnecting || sendInFlightRef.current) return;
-    if (activePendingProgress) {
-      onAdvanceActivePendingUserInput();
-      return;
-    }
-    const promptForSend = promptRef.current;
-    const {
-      trimmedPrompt: trimmed,
-      sendableTerminalContexts: sendableComposerTerminalContexts,
-      expiredTerminalContextCount,
-      hasSendableContent,
-    } = deriveComposerSendState({
-      prompt: promptForSend,
-      imageCount: composerImages.length,
-      terminalContexts: composerTerminalContexts,
-    });
-    if (showPlanFollowUpPrompt && activeProposedPlan) {
-      const followUp = resolvePlanFollowUpSubmission({
-        draftText: trimmed,
-        planMarkdown: activeProposedPlan.planMarkdown,
-      });
-      promptRef.current = "";
-      clearComposerDraftContent(activeThread.id);
-      setComposerHighlightedItemId(null);
-      setComposerCursor(0);
-      setComposerTrigger(null);
-      await onSubmitPlanFollowUp({
-        text: followUp.text,
-        interactionMode: followUp.interactionMode,
-      });
+    if (!api || !activeThread || !activeProject || isSendBusy || isConnecting || sendInFlightRef.current) {
       return;
     }
-    const standaloneSlashCommand =
-      composerImages.length === 0 && sendableComposerTerminalContexts.length === 0
-        ? parseStandaloneComposerSlashCommand(trimmed)
-        : null;
-    if (standaloneSlashCommand) {
-      handleInteractionModeChange(standaloneSlashCommand);
-      promptRef.current = "";
-      clearComposerDraftContent(activeThread.id);
-      setComposerHighlightedItemId(null);
-      setComposerCursor(0);
-      setComposerTrigger(null);
-      return;
-    }
-    if (!hasSendableContent) {
-      if (expiredTerminalContextCount > 0) {
-        const toastCopy = buildExpiredTerminalContextToastCopy(
-          expiredTerminalContextCount,
-          "empty",
-        );
-        toastManager.add({
-          type: "warning",
-          title: toastCopy.title,
-          description: toastCopy.description,
-        });
-      }
-      return;
-    }
-    if (!activeProject) return;
+
     const threadIdForSend = activeThread.id;
     const isFirstMessage = !isServerThread || activeThread.messages.length === 0;
     const baseBranchForWorktree =
@@ -2710,11 +2749,18 @@ export default function ChatView({ threadId }: ChatViewProps) {
       return;
     }
 
+    const {
+      promptForSend,
+      trimmedPrompt,
+      composerImagesSnapshot,
+      composerTerminalContextsSnapshot,
+      clearComposerDraft,
+      expiredTerminalContextCount,
+    } = input;
+
     sendInFlightRef.current = true;
     beginLocalDispatch({ preparingWorktree: Boolean(baseBranchForWorktree) });
 
-    const composerImagesSnapshot = [...composerImages];
-    const composerTerminalContextsSnapshot = [...sendableComposerTerminalContexts];
     const messageTextForSend = appendTerminalContextsToPrompt(
       promptForSend,
       composerTerminalContextsSnapshot,
@@ -2772,11 +2818,13 @@ export default function ChatView({ threadId }: ChatViewProps) {
         description: toastCopy.description,
       });
     }
-    promptRef.current = "";
-    clearComposerDraftContent(threadIdForSend);
-    setComposerHighlightedItemId(null);
-    setComposerCursor(0);
-    setComposerTrigger(null);
+    if (clearComposerDraft) {
+      promptRef.current = "";
+      clearComposerDraftContent(threadIdForSend);
+      setComposerHighlightedItemId(null);
+      setComposerCursor(0);
+      setComposerTrigger(null);
+    }
 
     let createdServerThreadForLocalDraft = false;
     let turnStartSucceeded = false;
@@ -2815,7 +2863,7 @@ export default function ChatView({ threadId }: ChatViewProps) {
           firstComposerImageName = firstComposerImage.name;
         }
       }
-      let titleSeed = trimmed;
+      let titleSeed = trimmedPrompt;
       if (!titleSeed) {
         if (firstComposerImageName) {
           titleSeed = `Image: ${firstComposerImageName}`;
@@ -2927,6 +2975,7 @@ export default function ChatView({ threadId }: ChatViewProps) {
           .catch(() => undefined);
       }
       if (
+        clearComposerDraft &&
         !turnStartSucceeded &&
         promptRef.current.length === 0 &&
         composerImagesRef.current.length === 0 &&
@@ -2958,6 +3007,152 @@ export default function ChatView({ threadId }: ChatViewProps) {
     }
   };
 
+  const onSend = async (e?: { preventDefault: () => void }) => {
+    e?.preventDefault();
+    const api = readNativeApi();
+    if (!api || !activeThread || isSendBusy || isConnecting || sendInFlightRef.current) return;
+    if (activePendingProgress) {
+      onAdvanceActivePendingUserInput();
+      return;
+    }
+    const promptForSend = promptRef.current;
+    const {
+      trimmedPrompt: trimmed,
+      sendableTerminalContexts: sendableComposerTerminalContexts,
+      expiredTerminalContextCount,
+      hasSendableContent,
+    } = deriveComposerSendState({
+      prompt: promptForSend,
+      imageCount: composerImages.length,
+      terminalContexts: composerTerminalContexts,
+    });
+    if (showPlanFollowUpPrompt && activeProposedPlan) {
+      const followUp = resolvePlanFollowUpSubmission({
+        draftText: trimmed,
+        planMarkdown: activeProposedPlan.planMarkdown,
+      });
+      promptRef.current = "";
+      clearComposerDraftContent(activeThread.id);
+      setComposerHighlightedItemId(null);
+      setComposerCursor(0);
+      setComposerTrigger(null);
+      await onSubmitPlanFollowUp({
+        text: followUp.text,
+        interactionMode: followUp.interactionMode,
+      });
+      return;
+    }
+    const standaloneSlashCommand =
+      composerImages.length === 0 && sendableComposerTerminalContexts.length === 0
+        ? parseStandaloneComposerSlashCommand(trimmed)
+        : null;
+    if (standaloneSlashCommand) {
+      handleInteractionModeChange(standaloneSlashCommand);
+      promptRef.current = "";
+      clearComposerDraftContent(activeThread.id);
+      setComposerHighlightedItemId(null);
+      setComposerCursor(0);
+      setComposerTrigger(null);
+      return;
+    }
+    if (!hasSendableContent) {
+      if (expiredTerminalContextCount > 0) {
+        const toastCopy = buildExpiredTerminalContextToastCopy(
+          expiredTerminalContextCount,
+          "empty",
+        );
+        toastManager.add({
+          type: "warning",
+          title: toastCopy.title,
+          description: toastCopy.description,
+        });
+      }
+      return;
+    }
+    if (!activeProject) return;
+    await submitComposerTurn({
+      promptForSend,
+      trimmedPrompt: trimmed,
+      composerImagesSnapshot: [...composerImages],
+      composerTerminalContextsSnapshot: [...sendableComposerTerminalContexts],
+      clearComposerDraft: true,
+      expiredTerminalContextCount,
+    });
+  };
+
+  const onStartEditUserMessage = useCallback(async (message: TimelineUserChatMessage) => {
+    setEditingUserMessageId(message.id);
+    const displayed = deriveDisplayedUserMessageState(message.text);
+    setEditingUserMessageText(displayed.visibleText);
+
+    const nextImages = await Promise.all(
+      (message.attachments ?? [])
+        .filter(
+          (
+            attachment,
+          ): attachment is Extract<
+            NonNullable<ChatMessage["attachments"]>[number],
+            { type: "image" }
+          > => attachment.type === "image",
+        )
+        .map(materializeMessageImageAttachmentForEdit),
+    );
+
+    setEditingUserMessageImages((existing) => {
+      for (const image of existing) {
+        if (!nextImages.some((candidate) => candidate?.previewUrl === image.previewUrl)) {
+          revokeBlobPreviewUrl(image.previewUrl);
+        }
+      }
+      return nextImages.flatMap((image) => (image ? [image] : []));
+    });
+  }, []);
+
+  const onCancelEditUserMessage = useCallback(() => {
+    setEditingUserMessageId(null);
+    setEditingUserMessageText("");
+    setEditingUserMessageImages((existing) => {
+      for (const image of existing) {
+        revokeBlobPreviewUrl(image.previewUrl);
+      }
+      return [];
+    });
+  }, []);
+
+  const onSubmitEditUserMessage = async (message: TimelineUserChatMessage) => {
+    const nextText = editingUserMessageText.trim();
+    if (!activeThread || (nextText.length === 0 && editingUserMessageImages.length === 0)) {
+      return;
+    }
+
+    const targetTurnCount = revertTurnCountByUserMessageId.get(message.id);
+    if (typeof targetTurnCount !== "number") {
+      setThreadError(activeThread.id, "This message can no longer be edited.");
+      return;
+    }
+
+    const reverted = await onRevertToTurnCount(targetTurnCount, { confirm: false });
+    if (!reverted) {
+      return;
+    }
+
+    await waitForThreadMessageRemoval(activeThread.id, message.id, EDIT_REVERT_SYNC_TIMEOUT_MS);
+
+    setEditingUserMessageId(null);
+    setEditingUserMessageText("");
+    const nextImages = editingUserMessageImages;
+    setEditingUserMessageImages([]);
+
+    await submitComposerTurn({
+      promptForSend: nextText,
+      trimmedPrompt: nextText,
+      composerImagesSnapshot: nextImages,
+      composerTerminalContextsSnapshot: [],
+      clearComposerDraft: false,
+      expiredTerminalContextCount: 0,
+    });
+  };
+
   const onInterrupt = async () => {
     const api = readNativeApi();
     if (!api || !activeThread) return;
@@ -3832,6 +4027,17 @@ export default function ChatView({ threadId }: ChatViewProps) {
                 revertTurnCountByUserMessageId={revertTurnCountByUserMessageId}
                 onRevertUserMessage={onRevertUserMessage}
                 isRevertingCheckpoint={isRevertingCheckpoint}
+                isSendBusy={isSendBusy}
+                editingUserMessageId={editingUserMessageId}
+                editingUserMessageText={editingUserMessageText}
+                editingUserMessageImages={editingUserMessageImages}
+                onStartEditUserMessage={onStartEditUserMessage}
+                onChangeEditingUserMessageText={setEditingUserMessageText}
+                onAddEditingUserMessageImages={addEditingUserMessageImages}
+                onRemoveEditingUserMessageImage={removeEditingUserMessageImage}
+                onEditUserMessagePaste={onEditUserMessagePaste}
+                onCancelEditUserMessage={onCancelEditUserMessage}
+                onSubmitEditUserMessage={onSubmitEditUserMessage}
                 onImageExpand={onExpandTimelineImage}
                 markdownCwd={gitCwd ?? undefined}
                 resolvedTheme={resolvedTheme}
diff --git a/apps/web/src/components/chat/MessagesTimeline.test.tsx b/apps/web/src/components/chat/MessagesTimeline.test.tsx
index 692438c74a..974eabb7be 100644
--- a/apps/web/src/components/chat/MessagesTimeline.test.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.test.tsx
@@ -84,6 +84,17 @@ describe("MessagesTimeline", () => {
         revertTurnCountByUserMessageId={new Map()}
         onRevertUserMessage={() => {}}
         isRevertingCheckpoint={false}
+        isSendBusy={false}
+        editingUserMessageId={null}
+        editingUserMessageText=""
+        editingUserMessageImages={[]}
+        onStartEditUserMessage={() => {}}
+        onChangeEditingUserMessageText={() => {}}
+        onAddEditingUserMessageImages={() => {}}
+        onRemoveEditingUserMessageImage={() => {}}
+        onEditUserMessagePaste={() => {}}
+        onCancelEditUserMessage={() => {}}
+        onSubmitEditUserMessage={() => {}}
         onImageExpand={() => {}}
         markdownCwd={undefined}
         resolvedTheme="light"
@@ -129,6 +140,17 @@ describe("MessagesTimeline", () => {
         revertTurnCountByUserMessageId={new Map()}
         onRevertUserMessage={() => {}}
         isRevertingCheckpoint={false}
+        isSendBusy={false}
+        editingUserMessageId={null}
+        editingUserMessageText=""
+        editingUserMessageImages={[]}
+        onStartEditUserMessage={() => {}}
+        onChangeEditingUserMessageText={() => {}}
+        onAddEditingUserMessageImages={() => {}}
+        onRemoveEditingUserMessageImage={() => {}}
+        onEditUserMessagePaste={() => {}}
+        onCancelEditUserMessage={() => {}}
+        onSubmitEditUserMessage={() => {}}
         onImageExpand={() => {}}
         markdownCwd={undefined}
         resolvedTheme="light"
diff --git a/apps/web/src/components/chat/MessagesTimeline.tsx b/apps/web/src/components/chat/MessagesTimeline.tsx
index 8cb8b89684..db19df7c52 100644
--- a/apps/web/src/components/chat/MessagesTimeline.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.tsx
@@ -1,4 +1,8 @@
-import { type MessageId, type TurnId } from "@t3tools/contracts";
+import {
+  type MessageId,
+  PROVIDER_SEND_TURN_MAX_ATTACHMENTS,
+  type TurnId,
+} from "@t3tools/contracts";
 import {
   memo,
   useCallback,
@@ -7,6 +11,7 @@ import {
   useMemo,
   useRef,
   useState,
+  type ClipboardEvent,
   type ReactNode,
 } from "react";
 import {
@@ -26,14 +31,19 @@ import {
   EyeIcon,
   GlobeIcon,
   HammerIcon,
+  ImagePlusIcon,
   type LucideIcon,
+  PencilIcon,
   SquarePenIcon,
   TerminalIcon,
   Undo2Icon,
   WrenchIcon,
+  XIcon,
   ZapIcon,
 } from "lucide-react";
 import { Button } from "../ui/button";
+import { Textarea } from "../ui/textarea";
+import { type ComposerImageAttachment } from "../../composerDraftStore";
 import { clamp } from "effect/Number";
 import { buildExpandedImagePreview, ExpandedImagePreview } from "./ExpandedImagePreview";
 import { ProposedPlanCard } from "./ProposedPlanCard";
@@ -61,6 +71,11 @@ import {
   textContainsInlineTerminalContextLabels,
 } from "./userMessageTerminalContexts";
 
+export type TimelineUserChatMessage = Extract<
+  ReturnType<typeof deriveTimelineEntries>[number],
+  { kind: "message" }
+>["message"];
+
 const ALWAYS_UNVIRTUALIZED_TAIL_ROWS = 8;
 
 interface MessagesTimelineProps {
@@ -80,6 +95,17 @@ interface MessagesTimelineProps {
   revertTurnCountByUserMessageId: Map<MessageId, number>;
   onRevertUserMessage: (messageId: MessageId) => void;
   isRevertingCheckpoint: boolean;
+  isSendBusy: boolean;
+  editingUserMessageId: MessageId | null;
+  editingUserMessageText: string;
+  editingUserMessageImages: ComposerImageAttachment[];
+  onStartEditUserMessage: (message: TimelineUserChatMessage) => void;
+  onChangeEditingUserMessageText: (value: string) => void;
+  onAddEditingUserMessageImages: (files: File[]) => void;
+  onRemoveEditingUserMessageImage: (imageId: string) => void;
+  onEditUserMessagePaste: (event: ClipboardEvent<HTMLTextAreaElement>) => void;
+  onCancelEditUserMessage: () => void;
+  onSubmitEditUserMessage: (message: TimelineUserChatMessage) => void;
   onImageExpand: (preview: ExpandedImagePreview) => void;
   markdownCwd: string | undefined;
   resolvedTheme: "light" | "dark";
@@ -115,6 +141,17 @@ export const MessagesTimeline = memo(function MessagesTimeline({
   revertTurnCountByUserMessageId,
   onRevertUserMessage,
   isRevertingCheckpoint,
+  isSendBusy,
+  editingUserMessageId,
+  editingUserMessageText,
+  editingUserMessageImages,
+  onStartEditUserMessage,
+  onChangeEditingUserMessageText,
+  onAddEditingUserMessageImages,
+  onRemoveEditingUserMessageImage,
+  onEditUserMessagePaste,
+  onCancelEditUserMessage,
+  onSubmitEditUserMessage,
   onImageExpand,
   markdownCwd,
   resolvedTheme,
@@ -354,85 +391,29 @@ export const MessagesTimeline = memo(function MessagesTimeline({
         })()}
 
       {row.kind === "message" &&
-        row.message.role === "user" &&
-        (() => {
-          const userImages = row.message.attachments ?? [];
-          const displayedUserMessage = deriveDisplayedUserMessageState(row.message.text);
-          const terminalContexts = displayedUserMessage.contexts;
-          const canRevertAgentWork = revertTurnCountByUserMessageId.has(row.message.id);
-          return (
-            <div className="flex justify-end">
-              <div className="group relative max-w-[80%] rounded-2xl rounded-br-sm border border-border bg-secondary px-4 py-3">
-                {userImages.length > 0 && (
-                  <div className="mb-2 grid max-w-[420px] grid-cols-2 gap-2">
-                    {userImages.map(
-                      (image: NonNullable<TimelineMessage["attachments"]>[number]) => (
-                        <div
-                          key={image.id}
-                          className="overflow-hidden rounded-lg border border-border/80 bg-background/70"
-                        >
-                          {image.previewUrl ? (
-                            <button
-                              type="button"
-                              className="h-full w-full cursor-zoom-in"
-                              aria-label={`Preview ${image.name}`}
-                              onClick={() => {
-                                const preview = buildExpandedImagePreview(userImages, image.id);
-                                if (!preview) return;
-                                onImageExpand(preview);
-                              }}
-                            >
-                              <img
-                                src={image.previewUrl}
-                                alt={image.name}
-                                className="h-full max-h-[220px] w-full object-cover"
-                                onLoad={onTimelineImageLoad}
-                                onError={onTimelineImageLoad}
-                              />
-                            </button>
-                          ) : (
-                            <div className="flex min-h-[72px] items-center justify-center px-2 py-3 text-center text-[11px] text-muted-foreground/70">
-                              {image.name}
-                            </div>
-                          )}
-                        </div>
-                      ),
-                    )}
-                  </div>
-                )}
-                {(displayedUserMessage.visibleText.trim().length > 0 ||
-                  terminalContexts.length > 0) && (
-                  <UserMessageBody
-                    text={displayedUserMessage.visibleText}
-                    terminalContexts={terminalContexts}
-                  />
-                )}
-                <div className="mt-1.5 flex items-center justify-end gap-2">
-                  <div className="flex items-center gap-1.5 opacity-0 transition-opacity duration-200 focus-within:opacity-100 group-hover:opacity-100">
-                    {displayedUserMessage.copyText && (
-                      <MessageCopyButton text={displayedUserMessage.copyText} />
-                    )}
-                    {canRevertAgentWork && (
-                      <Button
-                        type="button"
-                        size="xs"
-                        variant="outline"
-                        disabled={isRevertingCheckpoint || isWorking}
-                        onClick={() => onRevertUserMessage(row.message.id)}
-                        title="Revert to this message"
-                      >
-                        <Undo2Icon className="size-3" />
-                      </Button>
-                    )}
-                  </div>
-                  <p className="text-right text-[10px] text-muted-foreground/30">
-                    {formatTimestamp(row.message.createdAt, timestampFormat)}
-                  </p>
-                </div>
-              </div>
-            </div>
-          );
-        })()}
+        row.message.role === "user" && (
+          <EditableUserMessageTimelineRow
+            message={row.message}
+            timestampFormat={timestampFormat}
+            revertTurnCountByUserMessageId={revertTurnCountByUserMessageId}
+            onRevertUserMessage={onRevertUserMessage}
+            isRevertingCheckpoint={isRevertingCheckpoint}
+            isWorking={isWorking}
+            isSendBusy={isSendBusy}
+            onImageExpand={onImageExpand}
+            onTimelineImageLoad={onTimelineImageLoad}
+            editingUserMessageId={editingUserMessageId}
+            editingUserMessageText={editingUserMessageText}
+            editingUserMessageImages={editingUserMessageImages}
+            onStartEditUserMessage={onStartEditUserMessage}
+            onChangeEditingUserMessageText={onChangeEditingUserMessageText}
+            onAddEditingUserMessageImages={onAddEditingUserMessageImages}
+            onRemoveEditingUserMessageImage={onRemoveEditingUserMessageImage}
+            onEditUserMessagePaste={onEditUserMessagePaste}
+            onCancelEditUserMessage={onCancelEditUserMessage}
+            onSubmitEditUserMessage={onSubmitEditUserMessage}
+          />
+        )}
 
       {row.kind === "message" &&
         row.message.role === "assistant" &&
@@ -744,6 +725,255 @@ const UserMessageBody = memo(function UserMessageBody(props: {
   );
 });
 
+const EditableUserMessageTimelineRow = memo(function EditableUserMessageTimelineRow(props: {
+  message: TimelineUserChatMessage;
+  timestampFormat: TimestampFormat;
+  revertTurnCountByUserMessageId: Map<MessageId, number>;
+  onRevertUserMessage: (messageId: MessageId) => void;
+  isRevertingCheckpoint: boolean;
+  isWorking: boolean;
+  isSendBusy: boolean;
+  onImageExpand: (preview: ExpandedImagePreview) => void;
+  onTimelineImageLoad: () => void;
+  editingUserMessageId: MessageId | null;
+  editingUserMessageText: string;
+  editingUserMessageImages: ComposerImageAttachment[];
+  onStartEditUserMessage: (message: TimelineUserChatMessage) => void;
+  onChangeEditingUserMessageText: (value: string) => void;
+  onAddEditingUserMessageImages: (files: File[]) => void;
+  onRemoveEditingUserMessageImage: (imageId: string) => void;
+  onEditUserMessagePaste: (event: ClipboardEvent<HTMLTextAreaElement>) => void;
+  onCancelEditUserMessage: () => void;
+  onSubmitEditUserMessage: (message: TimelineUserChatMessage) => void;
+}) {
+  const {
+    message,
+    timestampFormat,
+    revertTurnCountByUserMessageId,
+    onRevertUserMessage,
+    isRevertingCheckpoint,
+    isWorking,
+    isSendBusy,
+    onImageExpand,
+    onTimelineImageLoad,
+    editingUserMessageId,
+    editingUserMessageText,
+    editingUserMessageImages,
+    onStartEditUserMessage,
+    onChangeEditingUserMessageText,
+    onAddEditingUserMessageImages,
+    onRemoveEditingUserMessageImage,
+    onEditUserMessagePaste,
+    onCancelEditUserMessage,
+    onSubmitEditUserMessage,
+  } = props;
+
+  const editTextareaRef = useRef<HTMLTextAreaElement | null>(null);
+  const editFileInputRef = useRef<HTMLInputElement | null>(null);
+  const userImages = message.attachments ?? [];
+  const displayedUserMessage = deriveDisplayedUserMessageState(message.text);
+  const terminalContexts = displayedUserMessage.contexts;
+  const canRevertAgentWork = revertTurnCountByUserMessageId.has(message.id);
+  const isEditing = editingUserMessageId === message.id;
+  const displayedImages = isEditing ? editingUserMessageImages : userImages;
+  const isBusy = isWorking || isSendBusy;
+
+  useEffect(() => {
+    if (!isEditing) {
+      return;
+    }
+    const textarea = editTextareaRef.current;
+    if (!textarea) {
+      return;
+    }
+    textarea.focus();
+    const selectionEnd = textarea.value.length;
+    textarea.setSelectionRange(selectionEnd, selectionEnd);
+  }, [isEditing]);
+
+  return (
+    <div className="flex justify-end">
+      <div className="group relative max-w-[80%] rounded-2xl rounded-br-sm border border-border bg-secondary px-4 py-3">
+        {displayedImages.length > 0 && (
+          <div className="mb-2 grid max-w-[420px] grid-cols-2 gap-2">
+            {displayedImages.map((image) => (
+              <div
+                key={image.id}
+                className="group/image relative overflow-hidden rounded-lg border border-border/80 bg-background/70"
+              >
+                {image.previewUrl ? (
+                  <button
+                    type="button"
+                    className="h-full w-full cursor-zoom-in"
+                    aria-label={`Preview ${image.name}`}
+                    onClick={() => {
+                      const preview = buildExpandedImagePreview(displayedImages, image.id);
+                      if (!preview) return;
+                      onImageExpand(preview);
+                    }}
+                  >
+                    <img
+                      src={image.previewUrl}
+                      alt={image.name}
+                      className="h-full max-h-[220px] w-full object-cover"
+                      onLoad={onTimelineImageLoad}
+                      onError={onTimelineImageLoad}
+                    />
+                  </button>
+                ) : (
+                  <div className="flex min-h-[72px] items-center justify-center px-2 py-3 text-center text-[11px] text-muted-foreground/70">
+                    {image.name}
+                  </div>
+                )}
+                {isEditing && (
+                  <Button
+                    type="button"
+                    variant="ghost"
+                    size="icon-xs"
+                    className="absolute top-1 right-1 bg-background/80 opacity-0 transition-opacity group-hover/image:opacity-100 hover:bg-background/90"
+                    onClick={() => onRemoveEditingUserMessageImage(image.id)}
+                    aria-label={`Remove ${image.name}`}
+                    disabled={isBusy}
+                  >
+                    <XIcon />
+                  </Button>
+                )}
+              </div>
+            ))}
+          </div>
+        )}
+        {isEditing ? (
+          <div className="space-y-2">
+            <input
+              ref={editFileInputRef}
+              type="file"
+              accept="image/*"
+              multiple
+              className="hidden"
+              onChange={(event) => {
+                const files = Array.from(event.target.files ?? []);
+                if (files.length > 0) {
+                  onAddEditingUserMessageImages(files);
+                }
+                event.currentTarget.value = "";
+              }}
+            />
+            <Textarea
+              ref={editTextareaRef}
+              value={editingUserMessageText}
+              onChange={(event) => onChangeEditingUserMessageText(event.target.value)}
+              onPaste={onEditUserMessagePaste}
+              onKeyDown={(event) => {
+                if ((event.metaKey || event.ctrlKey) && event.key === "Enter") {
+                  event.preventDefault();
+                  onSubmitEditUserMessage(message);
+                  return;
+                }
+                if (event.key === "Escape") {
+                  event.preventDefault();
+                  onCancelEditUserMessage();
+                }
+              }}
+              rows={Math.max(3, Math.min(10, editingUserMessageText.split("\n").length + 1))}
+              className="min-w-[18rem] w-full rounded-xl border-border/80 bg-background/70"
+              placeholder="Edit your message"
+              disabled={isBusy}
+              aria-label="Edit message"
+            />
+            <div className="flex items-center justify-between gap-2">
+              <div className="flex items-center gap-2 text-[10px] text-muted-foreground/55">
+                <p>Ctrl/Cmd+Enter to send</p>
+                <Button
+                  type="button"
+                  size="xs"
+                  variant="ghost"
+                  onClick={() => editFileInputRef.current?.click()}
+                  disabled={
+                    isBusy || editingUserMessageImages.length >= PROVIDER_SEND_TURN_MAX_ATTACHMENTS
+                  }
+                >
+                  <ImagePlusIcon className="size-3" />
+                  Image
+                </Button>
+              </div>
+              <div className="flex items-center gap-1.5">
+                <Button
+                  type="button"
+                  size="xs"
+                  variant="ghost"
+                  onClick={onCancelEditUserMessage}
+                  disabled={isBusy}
+                >
+                  Cancel
+                </Button>
+                <Button
+                  type="button"
+                  size="xs"
+                  variant="outline"
+                  onClick={() => onSubmitEditUserMessage(message)}
+                  disabled={
+                    isBusy ||
+                    (editingUserMessageText.trim().length === 0 &&
+                      editingUserMessageImages.length === 0)
+                  }
+                >
+                  <CheckIcon className="size-3" />
+                  Send
+                </Button>
+              </div>
+            </div>
+          </div>
+        ) : (
+          <>
+            {(displayedUserMessage.visibleText.trim().length > 0 ||
+              terminalContexts.length > 0) && (
+              <UserMessageBody
+                text={displayedUserMessage.visibleText}
+                terminalContexts={terminalContexts}
+              />
+            )}
+            <div className="mt-1.5 flex items-center justify-end gap-2">
+              <div className="flex items-center gap-1.5 opacity-0 transition-opacity duration-200 focus-within:opacity-100 group-hover:opacity-100">
+                {displayedUserMessage.copyText && (
+                  <MessageCopyButton text={displayedUserMessage.copyText} />
+                )}
+                {(displayedUserMessage.visibleText.trim().length > 0 || userImages.length > 0) &&
+                  canRevertAgentWork && (
+                    <Button
+                      type="button"
+                      size="xs"
+                      variant="outline"
+                      disabled={isBusy}
+                      onClick={() => onStartEditUserMessage(message)}
+                      title="Edit message"
+                    >
+                      <PencilIcon className="size-3" />
+                    </Button>
+                  )}
+                {canRevertAgentWork && (
+                  <Button
+                    type="button"
+                    size="xs"
+                    variant="outline"
+                    disabled={isRevertingCheckpoint || isBusy}
+                    onClick={() => onRevertUserMessage(message.id)}
+                    title="Revert to this message"
+                  >
+                    <Undo2Icon className="size-3" />
+                  </Button>
+                )}
+              </div>
+              <p className="text-right text-[10px] text-muted-foreground/30">
+                {formatTimestamp(message.createdAt, timestampFormat)}
+              </p>
+            </div>
+          </>
+        )}
+      </div>
+    </div>
+  );
+});
+
 function workToneIcon(tone: TimelineWorkEntry["tone"]): {
   icon: LucideIcon;
   className: string;
diff --git a/apps/web/src/components/chat/MessagesTimeline.virtualization.browser.tsx b/apps/web/src/components/chat/MessagesTimeline.virtualization.browser.tsx
index 1e947a3c84..5bc78fe565 100644
--- a/apps/web/src/components/chat/MessagesTimeline.virtualization.browser.tsx
+++ b/apps/web/src/components/chat/MessagesTimeline.virtualization.browser.tsx
@@ -164,6 +164,17 @@ function createBaseTimelineProps(input: {
     revertTurnCountByUserMessageId: new Map(),
     onRevertUserMessage: () => {},
     isRevertingCheckpoint: false,
+    isSendBusy: false,
+    editingUserMessageId: null,
+    editingUserMessageText: "",
+    editingUserMessageImages: [],
+    onStartEditUserMessage: () => {},
+    onChangeEditingUserMessageText: () => {},
+    onAddEditingUserMessageImages: () => {},
+    onRemoveEditingUserMessageImage: () => {},
+    onEditUserMessagePaste: () => {},
+    onCancelEditUserMessage: () => {},
+    onSubmitEditUserMessage: () => {},
     onImageExpand: () => {},
     markdownCwd: MARKDOWN_CWD,
     resolvedTheme: "light",