diff --git a/apps/server/src/terminal/Layers/Manager.test.ts b/apps/server/src/terminal/Layers/Manager.test.ts
index 2937c90b..fec3e1cf 100644
--- a/apps/server/src/terminal/Layers/Manager.test.ts
+++ b/apps/server/src/terminal/Layers/Manager.test.ts
@@ -8,6 +8,7 @@ import {
   type TerminalOpenInput,
   type TerminalRestartInput,
 } from "@t3tools/contracts";
+import { MOUSE_REPORTING_RESET_SEQUENCE } from "@t3tools/shared/terminalThreads";
 import { afterEach, describe, expect, it } from "vitest";
 
 import {
@@ -178,6 +179,16 @@ function multiTerminalHistoryLogPath(
   return path.join(logsDir, multiTerminalHistoryLogName(threadId, terminalId));
 }
 
+/**
+ * Snapshots returned for a restored / re-attached session append a mouse-mode
+ * reset to the replayed history so a freshly attached xterm never starts with
+ * mouse reporting enabled. Tests that assert on restored history use this to
+ * express the expected transcript without repeating the reset sequence.
+ */
+function withMouseReset(history: string): string {
+  return `${history}${MOUSE_REPORTING_RESET_SEQUENCE}`;
+}
+
 describe("TerminalManager", () => {
   const tempDirs: string[] = [];
 
@@ -472,8 +483,7 @@ describe("TerminalManager", () => {
     await manager.close({ threadId: "thread-1" });
 
     const reopened = await manager.open(openInput());
-    const nonEmptyLines = reopened.history.split("\n").filter((line) => line.length > 0);
-    expect(nonEmptyLines).toEqual(["line2", "line3", "line4"]);
+    expect(reopened.history).toBe(withMouseReset("line2\nline3\nline4\n"));
 
     manager.dispose();
   });
@@ -494,7 +504,7 @@ describe("TerminalManager", () => {
     await manager.close({ threadId: "thread-1" });
 
     const reopened = await manager.open(openInput());
-    expect(reopened.history).toBe("prompt \u001b[32mok\u001b[0m done\n");
+    expect(reopened.history).toBe(withMouseReset("prompt \u001b[32mok\u001b[0m done\n"));
 
     manager.dispose();
   });
@@ -516,7 +526,7 @@ describe("TerminalManager", () => {
     await manager.close({ threadId: "thread-1" });
 
     const reopened = await manager.open(openInput());
-    expect(reopened.history).toBe("before clear\nprompt \u001b[36mdone\u001b[0m\n");
+    expect(reopened.history).toBe(withMouseReset("before clear\nprompt \u001b[36mdone\u001b[0m\n"));
 
     manager.dispose();
   });
@@ -536,7 +546,7 @@ describe("TerminalManager", () => {
 
     const reopened = await manager.open(openInput());
     expect(reopened.history).toBe(
-      "instant prompt\nwarning output\nfinal prompt \u001b[35m❯\u001b[0m ",
+      withMouseReset("instant prompt\nwarning output\nfinal prompt \u001b[35m❯\u001b[0m "),
     );
 
     manager.dispose();
@@ -556,7 +566,9 @@ describe("TerminalManager", () => {
     await manager.close({ threadId: "thread-1" });
 
     const reopened = await manager.open(openInput());
-    expect(reopened.history).toBe("first prompt\r\u001b[0m\u001b[38;5;175m❯\u001b[0m ");
+    expect(reopened.history).toBe(
+      withMouseReset("first prompt\r\u001b[0m\u001b[38;5;175m❯\u001b[0m "),
+    );
 
     manager.dispose();
   });
@@ -575,7 +587,7 @@ describe("TerminalManager", () => {
     await manager.close({ threadId: "thread-1" });
 
     const reopened = await manager.open(openInput());
-    expect(reopened.history).toBe("before \u001b(Bafter\n");
+    expect(reopened.history).toBe(withMouseReset("before \u001b(Bafter\n"));
 
     manager.dispose();
   });
@@ -594,7 +606,54 @@ describe("TerminalManager", () => {
     await manager.close({ threadId: "thread-1" });
 
     const reopened = await manager.open(openInput());
-    expect(reopened.history).toBe("before \u001b(Bafter\n");
+    expect(reopened.history).toBe(withMouseReset("before \u001b(Bafter\n"));
+
+    manager.dispose();
+  });
+
+  it("appends a mouse-mode reset when re-attaching to a surviving terminal session", async () => {
+    const { manager, ptyAdapter } = makeManager();
+    await manager.open(openInput());
+    const process = ptyAdapter.processes[0];
+    expect(process).toBeDefined();
+    if (!process) return;
+
+    // A TUI enabled mouse reporting; it is no longer attached to consume events.
+    process.emitData("mouse-tui prompt\n");
+
+    // Re-attaching to the still-running session must not spawn a new pty and
+    // must hand back history that disables mouse reporting in the fresh xterm.
+    const reattached = await manager.open(openInput());
+    expect(ptyAdapter.spawnInputs).toHaveLength(1);
+    expect(reattached.history).toBe(withMouseReset("mouse-tui prompt\n"));
+    expect(reattached.history.endsWith(MOUSE_REPORTING_RESET_SEQUENCE)).toBe(true);
+
+    manager.dispose();
+  });
+
+  it("appends a mouse-mode reset when restoring a terminal session from persisted history", async () => {
+    const { manager, ptyAdapter } = makeManager();
+    await manager.open(openInput());
+    const process = ptyAdapter.processes[0];
+    expect(process).toBeDefined();
+    if (!process) return;
+
+    process.emitData("restored prompt\n");
+    await manager.close({ threadId: "thread-1" });
+
+    // Restoring from disk spawns a fresh pty, but the replayed history must
+    // still leave the re-created xterm with mouse reporting disabled.
+    const restored = await manager.open(openInput());
+    expect(ptyAdapter.spawnInputs).toHaveLength(2);
+    expect(restored.history).toBe(withMouseReset("restored prompt\n"));
+
+    manager.dispose();
+  });
+
+  it("does not append a mouse-mode reset to an empty terminal history", async () => {
+    const { manager } = makeManager();
+    const snapshot = await manager.open(openInput());
+    expect(snapshot.history).toBe("");
 
     manager.dispose();
   });
@@ -708,7 +767,7 @@ describe("TerminalManager", () => {
 
     const snapshot = await manager.open(openInput());
 
-    expect(snapshot.history).toBe("legacy-line\n");
+    expect(snapshot.history).toBe(withMouseReset("legacy-line\n"));
     expect(fs.existsSync(nextPath)).toBe(true);
     expect(fs.readFileSync(nextPath, "utf8")).toBe("legacy-line\n");
     expect(fs.existsSync(legacyPath)).toBe(false);
diff --git a/apps/server/src/terminal/Layers/Manager.ts b/apps/server/src/terminal/Layers/Manager.ts
index 500279f8..a187b498 100644
--- a/apps/server/src/terminal/Layers/Manager.ts
+++ b/apps/server/src/terminal/Layers/Manager.ts
@@ -21,6 +21,7 @@ import {
   deriveTerminalProcessIdentity,
   deriveTerminalTitleSignalIdentity,
   terminalCliKindFromValue,
+  MOUSE_REPORTING_RESET_SEQUENCE,
   T3CODE_TERMINAL_HOOK_OSC_PREFIX,
   T3CODE_TERMINAL_CLI_KIND_ENV_KEY,
   type TerminalActivityState,
@@ -824,6 +825,22 @@ function sanitizePersistedTerminalHistory(history: string): string {
   return sanitizeTerminalHistoryChunk("", history).visibleText;
 }
 
+/**
+ * Build the history payload returned in a session snapshot.
+ *
+ * Snapshots are replayed into a freshly attached xterm on open / re-attach /
+ * restore. Restored history can leave that xterm with mouse reporting enabled
+ * (the TUI that originally turned it on is no longer attached to consume the
+ * events), so raw `CSI < … M/m` mouse sequences spill into the shell as
+ * garbage. Appending a mouse-mode reset guarantees the re-attached terminal
+ * starts with mouse reporting off; it is a no-op for an empty history (a brand
+ * new session has nothing to replay).
+ */
+function snapshotHistory(history: string): string {
+  if (history.length === 0) return history;
+  return `${history}${MOUSE_REPORTING_RESET_SEQUENCE}`;
+}
+
 interface TerminalManagerEvents {
   event: [event: TerminalEvent];
 }
@@ -1888,7 +1905,7 @@ export class TerminalManagerRuntime extends EventEmitter<TerminalManagerEvents>
       cwd: session.cwd,
       status: session.status,
       pid: session.pid,
-      history: session.history,
+      history: snapshotHistory(session.history),
       exitCode: session.exitCode,
       exitSignal: session.exitSignal,
       updatedAt: session.updatedAt,
diff --git a/apps/web/src/components/terminal/terminalRuntime.ts b/apps/web/src/components/terminal/terminalRuntime.ts
index 2496dcad..d01c3e8a 100644
--- a/apps/web/src/components/terminal/terminalRuntime.ts
+++ b/apps/web/src/components/terminal/terminalRuntime.ts
@@ -13,6 +13,7 @@ import {
   defaultTerminalTitleForCliKind,
   consumeTerminalIdentityInput,
   deriveTerminalOutputIdentity,
+  MOUSE_REPORTING_RESET_SEQUENCE,
 } from "@t3tools/shared/terminalThreads";
 import { Terminal } from "@xterm/xterm";
 
@@ -56,7 +57,11 @@ function resetForSnapshotReplay(entry: TerminalRuntimeEntry): void {
   entry.outputIdentityBuffer = "";
   clearPendingWrites(entry);
   clearDeferredWrites(entry);
-  entry.terminal.write("\u001bc");
+  // RIS (`\u001bc`) resets the emulator, but xterm.js does not reliably clear
+  // DEC private mouse-tracking modes on RIS. Explicitly disable mouse reporting
+  // so a re-attached terminal never starts in a state where mouse movement
+  // spews raw `CSI < … M/m` sequences into the shell.
+  entry.terminal.write(`\u001bc${MOUSE_REPORTING_RESET_SEQUENCE}`);
 }
 
 function replaySnapshotHistory(entry: TerminalRuntimeEntry, history: string): void {
diff --git a/packages/shared/src/terminalThreads.ts b/packages/shared/src/terminalThreads.ts
index af17399d..6f5aecc3 100644
--- a/packages/shared/src/terminalThreads.ts
+++ b/packages/shared/src/terminalThreads.ts
@@ -11,6 +11,21 @@ export type TerminalVisualState = "idle" | TerminalActivityState;
 export type TerminalAgentHookEventType = "Start" | "Stop" | "PermissionRequest";
 export const T3CODE_TERMINAL_CLI_KIND_ENV_KEY = "T3CODE_TERMINAL_CLI_KIND";
 export const T3CODE_TERMINAL_HOOK_OSC_PREFIX = "633;T3CODE_AGENT_EVENT=";
+
+/**
+ * Escape sequence that disables every xterm mouse-reporting mode.
+ *
+ * Covers X10/normal/button/any-event tracking plus the SGR and urxvt extended
+ * coordinate encodings. Replaying restored terminal history into a freshly
+ * attached xterm can leave it with mouse reporting enabled — the TUI that
+ * originally turned it on (e.g. `claude`) is no longer attached to consume the
+ * events, so raw `CSI < … M/m` sequences spill into the shell as garbage.
+ * Emitting this on the re-attach / snapshot-replay path guarantees the restored
+ * terminal starts with mouse reporting off.
+ */
+export const MOUSE_REPORTING_RESET_SEQUENCE =
+  "\u001b[?1000l\u001b[?1002l\u001b[?1003l\u001b[?1006l\u001b[?1015l";
+
 export const MANAGED_TERMINAL_COMMAND_NAME_BY_CLI_KIND: Record<TerminalCliKind, string> = {
   codex: "codex",
   claude: "claude",