diff --git a/frontend/src/features/agents/CustomAgentChatView.test.tsx b/frontend/src/features/agents/CustomAgentChatView.test.tsx
index 606cadaa..dfbea426 100644
--- a/frontend/src/features/agents/CustomAgentChatView.test.tsx
+++ b/frontend/src/features/agents/CustomAgentChatView.test.tsx
@@ -1342,8 +1342,8 @@ describe("CustomAgentChatView", () => {
     });
 
     await screen.findByText("done");
-    expect(screen.getAllByText("Worker ← QA")).toHaveLength(1);
-    expect(screen.getAllByText("validate")).toHaveLength(1);
+    expect(screen.getAllByText("Worker ← QA")).toHaveLength(2);
+    expect(screen.getAllByText("validate")).toHaveLength(2);
     expect(screen.queryByText("Appel inter-agent")).toBeNull();
     expect(screen.queryByText("reply delivered")).toBeNull();
     expect(screen.queryByText("Tool")).toBeNull();
@@ -1353,6 +1353,99 @@ describe("CustomAgentChatView", () => {
     );
   });
 
+  it("keeps repeated MCP cycles visible when legacy progress has no progressId", async () => {
+    let emitChunk: ((chunk: unknown) => void) | null = null;
+    const agent = {
+      launchAgentChat: vi.fn(),
+      reattachAgentChat: vi.fn(async (sessionId: string) => ({
+        sessionId,
+        scrollback: [],
+      })),
+      sendAgentChat: vi.fn(
+        (_sessionId: string, _prompt: string, onChunk: (chunk: unknown) => void) =>
+          new Promise<void>((resolve) => {
+            emitChunk = (chunk: unknown) => {
+              onChunk(chunk);
+              if ((chunk as { kind?: string }).kind === "final") resolve();
+            };
+          }),
+      ),
+      cancelAgentChat: vi.fn(async () => {}),
+      closeAgentChat: vi.fn(async () => {}),
+    };
+
+    render(
+      <DIProvider
+        gateways={{
+          agent,
+          system: { pickFile: vi.fn(async () => null) },
+        } as unknown as Gateways}
+      >
+        <CustomAgentChatView
+          projectId="project-1"
+          agentId="agent-1"
+          agentName="Worker"
+          profile={profile}
+          cwd="/repo"
+          nodeId="node-1"
+          sessionId="chat-session-1"
+          conversationId="conversation-1"
+          onSessionId={vi.fn()}
+          onConversationId={vi.fn()}
+        />
+      </DIProvider>,
+    );
+
+    await waitFor(() =>
+      expect(agent.reattachAgentChat).toHaveBeenCalledWith(
+        "chat-session-1",
+        expect.any(Function),
+      ),
+    );
+
+    fireEvent.change(screen.getByLabelText(/message CLI custom/), {
+      target: { value: "read many tickets" },
+    });
+    fireEvent.click(screen.getByRole("button", { name: "Envoyer" }));
+    await waitFor(() => expect(emitChunk).not.toBeNull());
+
+    act(() => {
+      for (let index = 1; index <= 8; index += 1) {
+        emitChunk?.({
+          kind: "progress" as const,
+          progress: {
+            source: "ideaLocal" as const,
+            kind: "mcp" as const,
+            stage: "started" as const,
+            label: "idea_ticket_read",
+            toolName: "idea_ticket_read",
+            text: `reading ticket #${index}`,
+          },
+        });
+        emitChunk?.({
+          kind: "progress" as const,
+          progress: {
+            source: "ideaLocal" as const,
+            kind: "mcp" as const,
+            stage: "completed" as const,
+            label: "idea_ticket_read",
+            toolName: "idea_ticket_read",
+            text: `read ticket #${index}`,
+          },
+        });
+      }
+      emitChunk?.({ kind: "final", content: "done" });
+    });
+
+    await screen.findByText("done");
+    expect(screen.getAllByTestId("chat-tool-progress")).toHaveLength(8);
+    expect(screen.getAllByText("MCP")).toHaveLength(8);
+    expect(screen.getAllByText("idea_ticket_read")).toHaveLength(8);
+    expect(screen.getByText("read ticket #1")).toBeTruthy();
+    expect(screen.getByText("read ticket #8")).toBeTruthy();
+    expect(screen.queryByText("reading ticket #1")).toBeNull();
+  });
+
   it("deduplicates identical entity progress chunks", async () => {
     let emitChunk: ((chunk: unknown) => void) | null = null;
     const agent = {
diff --git a/frontend/src/features/agents/CustomAgentChatView.tsx b/frontend/src/features/agents/CustomAgentChatView.tsx
index 1f37b881..1c691a9d 100644
--- a/frontend/src/features/agents/CustomAgentChatView.tsx
+++ b/frontend/src/features/agents/CustomAgentChatView.tsx
@@ -64,7 +64,7 @@ type ChatTurn =
   | { role: "user"; text: string; attachments?: string[]; receivedAtMs?: number }
   | { role: "agent"; text: string; pending?: boolean; receivedAtMs?: number }
   | { role: "tool"; label: string; receivedAtMs?: number }
-  | { role: "progress"; progress: ReplyProgress; settled?: boolean }
+  | { role: "progress"; progress: ReplyProgress; settled?: boolean; progressKey?: string }
   | { role: "final"; text: string; receivedAtMs?: number }
   | { role: "error"; text: string; receivedAtMs?: number }
   | { role: "unknown"; text: string; receivedAtMs?: number };
@@ -291,11 +291,13 @@ function progressKey(progress: ReplyProgress): string {
 function progressUpsertKey(progress: ReplyProgress): string {
   const progressId = progress.progressId?.trim();
   if (progressId) return progressId;
-  const entity = progressEntityKey(progress);
-  if (entity) return `legacy-entity:${entity}`;
   return `legacy:${progressDisplayKey(progress)}`;
 }
 
+function turnProgressKey(turn: Extract<ChatTurn, { role: "progress" }>): string {
+  return turn.progressKey ?? progressUpsertKey(turn.progress);
+}
+
 function normalizedProgressToolName(progress: ReplyProgress): string | null {
   const name = progress.toolName ?? progress.label;
   const normalized = name.trim().toLowerCase();
@@ -328,6 +330,38 @@ function progressDisplayKey(progress: ReplyProgress): string {
   return progressKey(progress);
 }
 
+function legacyActiveProgressKey(progress: ReplyProgress): string | null {
+  const entity = progressEntityKey(progress);
+  if (!entity) return null;
+  if (progress.stage !== "started" && progress.stage !== "delta") return null;
+  return `legacy:${entity}\u0000started`;
+}
+
+function legacyCompletedDedupKey(progress: ReplyProgress): string | null {
+  const entity = progressEntityKey(progress);
+  if (!entity || progress.stage !== "completed") return null;
+  if (isDelegationProgress(progress)) return entity;
+  return `${entity}\u0000${progress.text ?? ""}`;
+}
+
+function findLastProgressIndex(
+  turns: ChatTurn[],
+  predicate: (turn: Extract<ChatTurn, { role: "progress" }>) => boolean,
+): number {
+  for (let index = turns.length - 1; index >= 0; index -= 1) {
+    const turn = turns[index];
+    if (turn.role === "progress" && predicate(turn)) return index;
+  }
+  return -1;
+}
+
+function legacyCompletedOccurrenceKey(
+  progress: ReplyProgress,
+  entry: ProgressIndexEntry,
+): string {
+  return `legacy-completed:${progressDisplayKey(progress)}\u0000${entry.firstOccurredAtMs}\u0000${entry.sequence}`;
+}
+
 interface ChatViewState {
   turns: ChatTurn[];
   progressIndex: Map<string, ProgressIndexEntry>;
@@ -346,13 +380,41 @@ function conversationCacheKey(
 }
 
 function appendProgress(state: ChatViewState, progress: ReplyProgress): ChatViewState {
-  const key = progressUpsertKey(progress);
-  const existingIndex = state.turns.findIndex(
-    (turn) => turn.role === "progress" && progressUpsertKey(turn.progress) === key,
+  let key = progressUpsertKey(progress);
+  let existingIndex = state.turns.findIndex(
+    (turn) => turn.role === "progress" && turnProgressKey(turn) === key,
   );
+
+  const activeKey =
+    !progress.progressId && progress.stage === "completed"
+      ? legacyActiveProgressKey({ ...progress, stage: "started" })
+      : null;
+  if (activeKey) {
+    const activeIndex = state.turns.findIndex(
+      (turn) => turn.role === "progress" && turnProgressKey(turn) === activeKey,
+    );
+    if (activeIndex >= 0) {
+      existingIndex = activeIndex;
+      key = activeKey;
+    }
+  }
+
+  const completedDedupKey = existingIndex < 0 ? legacyCompletedDedupKey(progress) : null;
+  if (completedDedupKey) {
+    existingIndex = findLastProgressIndex(
+      state.turns,
+      (turn) => legacyCompletedDedupKey(turn.progress) === completedDedupKey,
+    );
+    const existingTurn = existingIndex >= 0 ? state.turns[existingIndex] : null;
+    if (existingTurn?.role === "progress") {
+      key = turnProgressKey(existingTurn);
+    }
+  }
+
+  const existingTurn = existingIndex >= 0 ? state.turns[existingIndex] : null;
   const existingProgress =
-    existingIndex >= 0 && state.turns[existingIndex].role === "progress"
-      ? state.turns[existingIndex].progress
+    existingTurn?.role === "progress"
+      ? existingTurn.progress
       : null;
   const merged =
     existingProgress && progress.stage === "completed"
@@ -365,24 +427,30 @@ function appendProgress(state: ChatViewState, progress: ReplyProgress): ChatView
     progress.occurredAtMs ??
     Date.now();
   const sequence = existingEntry?.sequence ?? nextIndex.size;
-  nextIndex.set(key, { firstOccurredAtMs, sequence });
+  const nextEntry = { firstOccurredAtMs, sequence };
+  let nextKey = key;
+  if (!progress.progressId && progress.stage === "completed" && activeKey && key === activeKey) {
+    nextKey = legacyCompletedOccurrenceKey(merged, nextEntry);
+    nextIndex.delete(activeKey);
+  }
+  nextIndex.set(nextKey, nextEntry);
 
   if (existingIndex >= 0) {
     const nextTurns = [...state.turns];
-    nextTurns[existingIndex] = { role: "progress", progress: merged };
+    nextTurns[existingIndex] = { role: "progress", progress: merged, progressKey: nextKey };
     return { turns: nextTurns, progressIndex: nextIndex };
   }
 
   const insertAt = state.turns.findIndex((turn) => {
     if (turn.role !== "progress") return false;
-    const candidate = state.progressIndex.get(progressUpsertKey(turn.progress));
+    const candidate = state.progressIndex.get(turnProgressKey(turn));
     if (!candidate) return false;
     if (candidate.firstOccurredAtMs !== firstOccurredAtMs) {
       return candidate.firstOccurredAtMs > firstOccurredAtMs;
     }
     return candidate.sequence > sequence;
   });
-  const nextTurn = { role: "progress" as const, progress: merged };
+  const nextTurn = { role: "progress" as const, progress: merged, progressKey: nextKey };
   if (insertAt < 0) {
     return { turns: [...state.turns, nextTurn], progressIndex: nextIndex };
   }
@@ -408,9 +476,32 @@ function mergeCompletedProgress(
   };
 }
 
-function completeRunningProgress(turns: ChatTurn[]): ChatTurn[] {
+function progressShouldSettle(
+  turn: Extract<ChatTurn, { role: "progress" }>,
+  completedEntities: Set<string | null>,
+): boolean {
+  if (
+    turn.progress.kind === "turn" ||
+    (turn.progress.stage !== "started" && turn.progress.stage !== "delta")
+  ) {
+    return false;
+  }
+  const entity = progressEntityKey(turn.progress);
+  return Boolean(entity && completedEntities.has(entity));
+}
+
+function shouldCompleteProgress(
+  turn: Extract<ChatTurn, { role: "progress" }>,
+): boolean {
+  return (
+    turn.progress.kind !== "turn" &&
+    (turn.progress.stage === "started" || turn.progress.stage === "delta")
+  );
+}
+
+function completeChatViewProgress(state: ChatViewState): ChatViewState {
   const completedEntities = new Set(
-    turns
+    state.turns
       .filter(
         (turn): turn is Extract<ChatTurn, { role: "progress" }> =>
           turn.role === "progress" &&
@@ -419,40 +510,44 @@ function completeRunningProgress(turns: ChatTurn[]): ChatTurn[] {
       )
       .map((turn) => progressEntityKey(turn.progress)),
   );
-  return turns.map((turn) => {
-    if (
-      turn.role !== "progress" ||
-      turn.progress.kind === "turn" ||
-      (turn.progress.stage !== "started" && turn.progress.stage !== "delta")
-    ) {
-      return turn;
-    }
-    const entity = progressEntityKey(turn.progress);
-    if (entity && completedEntities.has(entity)) {
+
+  const nextIndex = new Map(state.progressIndex);
+  const turns = state.turns.map((turn) => {
+    if (turn.role !== "progress" || !shouldCompleteProgress(turn)) return turn;
+
+    const previousKey = turnProgressKey(turn);
+    const previousEntry = nextIndex.get(previousKey);
+    const entry =
+      previousEntry ?? {
+        firstOccurredAtMs: turn.progress.occurredAtMs ?? Date.now(),
+        sequence: nextIndex.size,
+      };
+    const completedProgress = {
+      ...turn.progress,
+      stage: "completed" as const,
+    };
+    const nextKey = turn.progress.progressId
+      ? progressUpsertKey(completedProgress)
+      : legacyCompletedOccurrenceKey(completedProgress, entry);
+    if (previousKey !== nextKey) nextIndex.delete(previousKey);
+    nextIndex.set(nextKey, entry);
+
+    if (progressShouldSettle(turn, completedEntities)) {
       return {
         ...turn,
         settled: true,
-        progress: {
-          ...turn.progress,
-          stage: "completed",
-        },
+        progress: completedProgress,
+        progressKey: nextKey,
       };
     }
     return {
       ...turn,
-      progress: {
-        ...turn.progress,
-        stage: "completed",
-      },
+      progress: completedProgress,
+      progressKey: nextKey,
     };
   });
-}
 
-function completeChatViewProgress(state: ChatViewState): ChatViewState {
-  return {
-    turns: completeRunningProgress(state.turns),
-    progressIndex: state.progressIndex,
-  };
+  return { turns, progressIndex: nextIndex };
 }
 
 function isRecoverableNoResponseTurn(turn: ChatTurn | undefined): boolean {
@@ -2206,7 +2301,7 @@ function ChatBubble({
     );
   }
   if (turn.role === "progress") {
-    const key = progressUpsertKey(turn.progress);
+    const key = turnProgressKey(turn);
     return (
       <ProgressBubble
         progress={turn.progress}