diff --git a/server/src/modules/computers/adapters/boat.test.ts b/server/src/modules/computers/adapters/boat.test.ts
index a988245d06..22096cee50 100644
--- a/server/src/modules/computers/adapters/boat.test.ts
+++ b/server/src/modules/computers/adapters/boat.test.ts
@@ -14,7 +14,7 @@ import { join } from "node:path";
 import { spawnSync } from "node:child_process";
 import { remoteProgram } from "./remote-program.js";
 import { afterEach, describe, it, expect, vi } from "vitest";
-import { boatBackend, processProgram } from "./boat.js";
+import { boatBackend, desktopReadinessProgram, processProgram } from "./boat.js";
 import { buildGitAuthInvocation } from "../../../services/git-credentials.js";
 import type { ComputerRecord } from "../domain/ledger.js";
 const record: ComputerRecord = {
@@ -384,3 +384,66 @@ case "$*" in *show*) printf '%s\\n' '${state}';; esac
     expect(existsSync(f.calls)).toBe(false);
   });
 });
+
+
+describe("Boat desktop input readiness", () => {
+  function desktopFixture(initiallyHealthy: boolean) {
+    const temp = realpathSync(mkdtempSync(join(tmpdir(), "computer-desktop-")));
+    roots.push(temp);
+    const runtime = join(temp, String(process.getuid!()));
+    const bin = join(temp, "bin");
+    const healthy = join(temp, "healthy");
+    const calls = join(temp, "repairs");
+    mkdirSync(runtime, { mode: 0o700 });
+    mkdirSync(bin);
+    if (initiallyHealthy) writeFileSync(healthy, "ready");
+    writeFileSync(join(bin, "ibus"), "#!/bin/sh\nprintf '%s\\n' 'unix:path=/test/ibus'\n", { mode: 0o700 });
+    writeFileSync(join(bin, "gdbus"), `#!/bin/sh\ntest -f '${healthy}'\n`, { mode: 0o700 });
+    writeFileSync(join(bin, "ibus-daemon"), `#!/bin/sh\nprintf '%s\\n' "$*" >> '${calls}'\ntouch '${healthy}'\n`, { mode: 0o700 });
+    const call = (program = desktopReadinessProgram) => spawnSync("python3", ["-c", program.replaceAll("/run/user/", `${temp}/`)], {
+      encoding: "utf8", env: { ...process.env, PATH: `${bin}:${process.env.PATH}` },
+    });
+    return { temp, runtime, healthy, calls, call };
+  }
+
+  it("preserves a healthy input service and emits no MCP protocol output", () => {
+    const f = desktopFixture(true);
+    const result = f.call();
+    expect(result.status).toBe(0);
+    expect(result.stdout).toBe("");
+    expect(existsSync(f.calls)).toBe(false);
+  });
+
+  it("repairs a disconnected restored socket and checks it again after another resume", () => {
+    const f = desktopFixture(false);
+    expect(f.call().status).toBe(0);
+    const expected = `--replace --daemonize --xim --address unix:path=${f.runtime}/paperclip-ibus/bus\n`;
+    expect(readFileSync(f.calls, "utf8")).toBe(expected);
+    expect(f.call().status).toBe(0);
+    expect(readFileSync(f.calls, "utf8")).toBe(expected);
+    rmSync(f.healthy);
+    expect(f.call().status).toBe(0);
+    expect(readFileSync(f.calls, "utf8")).toBe(expected.repeat(2));
+  });
+
+  it("rejects a symlink input directory without replacing the daemon", () => {
+    const f = desktopFixture(false);
+    symlinkSync(f.temp, join(f.runtime, "paperclip-ibus"));
+    const result = f.call();
+    expect(result.status).not.toBe(0);
+    expect(result.stderr).toContain("invalid desktop input directory");
+    expect(existsSync(f.calls)).toBe(false);
+  });
+
+  it("executes the existing Cua MCP process only after input readiness", () => {
+    const f = desktopFixture(false);
+    const tool = boatBackend(async () => "unused").computerTool();
+    const cua = join(f.temp, "cua");
+    writeFileSync(cua, `#!/bin/sh\nprintf '%s\\n' "$*"\n`, { mode: 0o700 });
+    expect(tool.command).toBe("python3");
+    const result = f.call(tool.args[1]!.replaceAll("/opt/ascii/cua-driver/cua-driver", cua));
+    expect(result.status).toBe(0);
+    expect(result.stdout).toBe("mcp --socket /run/ascii-cua/driver.sock\n");
+    expect(existsSync(f.healthy)).toBe(true);
+  });
+});
diff --git a/server/src/modules/computers/adapters/boat.ts b/server/src/modules/computers/adapters/boat.ts
index aecfbd3cd5..9e436b56a3 100644
--- a/server/src/modules/computers/adapters/boat.ts
+++ b/server/src/modules/computers/adapters/boat.ts
@@ -19,6 +19,38 @@ const desktopCache = new Map<
   string,
   { viewerUrl: string; expiresAt: string }
 >();
+export const desktopReadinessProgram = String.raw`
+import os,sys,json,stat,fcntl,subprocess,time
+# Boat restores its persistent home, but Unix sockets there can refer to stale
+# kernel listeners. Keep a healthy IBus unchanged; repair only a failed probe.
+uid=os.getuid();runtime='/run/user/'+str(uid)
+st=os.lstat(runtime)
+if not stat.S_ISDIR(st.st_mode) or st.st_uid!=uid:raise RuntimeError('invalid desktop runtime directory')
+env={**os.environ,'DISPLAY':':0','XAUTHORITY':'/home/user/.Xauthority','DBUS_SESSION_BUS_ADDRESS':'unix:path='+runtime+'/bus','XDG_RUNTIME_DIR':runtime,'IBUS_ENABLE_SYNC_MODE':'0'}
+env.pop('IBUS_ADDRESS',None)
+def healthy():
+ try:
+  address=subprocess.run(['ibus','address'],env=env,capture_output=True,text=True,timeout=5)
+  if address.returncode or not address.stdout.strip().startswith('unix:'):return False
+  return subprocess.run(['gdbus','call','--address',address.stdout.strip(),'--dest','org.freedesktop.IBus','--object-path','/org/freedesktop/IBus','--method','org.freedesktop.DBus.Peer.Ping'],env=env,capture_output=True,timeout=5).returncode==0
+ except subprocess.TimeoutExpired:return False
+root=runtime+'/paperclip-ibus'
+os.makedirs(root,mode=0o700,exist_ok=True)
+st=os.lstat(root)
+if not stat.S_ISDIR(st.st_mode) or st.st_uid!=uid:raise RuntimeError('invalid desktop input directory')
+os.chmod(root,0o700)
+fd=os.open(root+'/lock',os.O_CREAT|os.O_RDWR|os.O_NOFOLLOW,0o600)
+with os.fdopen(fd,'a') as lock:
+ fcntl.flock(lock,fcntl.LOCK_EX)
+ if not healthy():
+  result=subprocess.run(['ibus-daemon','--replace','--daemonize','--xim','--address','unix:path='+root+'/bus'],env=env,capture_output=True,timeout=20)
+  if result.returncode:raise RuntimeError('desktop input repair failed')
+  for attempt in range(10):
+   if healthy():break
+   time.sleep(0.2)
+  else:raise RuntimeError('desktop input did not become ready')
+`;
+
 export const processProgram = String.raw`
 import os,sys,json,fcntl,subprocess,shutil,re
 p=json.load(sys.stdin);base='/home/user/.paperclip-owners';os.makedirs(base,exist_ok=True)
@@ -389,7 +421,14 @@ print('{}')
     async renew(record) {
       await api(record, "PATCH", "", { ttlSeconds: 300 });
     },
+    computerTool() {
+      return {
+        command: "python3",
+        args: ["-c", `${desktopReadinessProgram}\nos.execv('/opt/ascii/cua-driver/cua-driver',['cua-driver','mcp','--socket','/run/ascii-cua/driver.sock'])`],
+      };
+    },
     async desktop(record) {
+      await execute(record, `${desktopReadinessProgram}\nprint('{}')`, {});
       const cached = desktopCache.get(record.id);
       if (cached && Date.parse(cached.expiresAt) > Date.now() + 60_000)
         return cached;
diff --git a/server/src/modules/computers/application/ports.ts b/server/src/modules/computers/application/ports.ts
index 896d68c786..84c4ba51c7 100644
--- a/server/src/modules/computers/application/ports.ts
+++ b/server/src/modules/computers/application/ports.ts
@@ -53,6 +53,7 @@ export interface ComputerBackend {
     id: string,
   ): Promise<{ id: string; status: string }>;
   renew(record: ComputerRecord): Promise<void>;
+  computerTool(): { command: string; args: string[] };
   desktop(
     record: ComputerRecord,
   ): Promise<{ viewerUrl: string; expiresAt: string }>;
diff --git a/server/src/modules/computers/application/service.test.ts b/server/src/modules/computers/application/service.test.ts
index 5de8a1d598..9d8a55d4fa 100644
--- a/server/src/modules/computers/application/service.test.ts
+++ b/server/src/modules/computers/application/service.test.ts
@@ -63,6 +63,7 @@ function fixture() {
     stop: vi.fn(async () => ({ id: "stop_1", status: stopStatus })),
     stopStatus: vi.fn(async () => ({ id: "stop_1", status: stopStatus })),
     renew: vi.fn(async () => {}),
+    computerTool: () => ({ command: "cua-driver", args: ["mcp"] }),
     desktop: vi.fn(async () => ({
       viewerUrl: "https://test.on.boat.dev/#credential",
       expiresAt: new Date(clock.getTime() + 540_000).toISOString(),
diff --git a/server/src/modules/computers/application/service.ts b/server/src/modules/computers/application/service.ts
index 292836dee0..0fdf020355 100644
--- a/server/src/modules/computers/application/service.ts
+++ b/server/src/modules/computers/application/service.ts
@@ -289,6 +289,7 @@ finally:
     return {
       owner: ownerRef,
       runner: runnerFor(false),
+      computerTool: backend.computerTool(),
       process: {
         runner: runnerFor(true),
         async ingress(input?: { port?: number; path?: string }) {
diff --git a/server/src/services/computer-environment-driver.ts b/server/src/services/computer-environment-driver.ts
index 9818dc8fc7..9a65627e29 100644
--- a/server/src/services/computer-environment-driver.ts
+++ b/server/src/services/computer-environment-driver.ts
@@ -131,6 +131,6 @@ export async function computerExecutionTarget(db: Db, lease: EnvironmentLease, i
       if (port !== binding.listenerPort) throw new Error("computer_runner_port_mismatch");
       return ingress(path);
     },
-    computerTool: { command: "/opt/ascii/cua-driver/cua-driver", args: ["mcp", "--socket", "/run/ascii-cua/driver.sock"] },
+    computerTool: binding.computerTool,
   };
 }