diff --git a/packages/electron-app/electron/main/process-manager.ts b/packages/electron-app/electron/main/process-manager.ts
index 80cbd71e..76ae2271 100644
--- a/packages/electron-app/electron/main/process-manager.ts
+++ b/packages/electron-app/electron/main/process-manager.ts
@@ -1,4 +1,4 @@
-import { spawn, type ChildProcess } from "child_process"
+import { spawn, spawnSync, type ChildProcess } from "child_process"
 import { app } from "electron"
 import { createRequire } from "module"
 import { EventEmitter } from "events"
@@ -82,6 +82,7 @@ export class CliProcessManager extends EventEmitter {
   private stdoutBuffer = ""
   private stderrBuffer = ""
   private bootstrapToken: string | null = null
+  private requestedStop = false
 
   async start(options: StartOptions): Promise<CliStatus> {
     if (this.child) {
@@ -91,6 +92,7 @@ export class CliProcessManager extends EventEmitter {
     this.stdoutBuffer = ""
     this.stderrBuffer = ""
     this.bootstrapToken = null
+    this.requestedStop = false
     this.updateStatus({ state: "starting", port: undefined, pid: undefined, url: undefined, error: undefined })
 
     const cliEntry = this.resolveCliEntry(options)
@@ -109,11 +111,13 @@ export class CliProcessManager extends EventEmitter {
       ? buildUserShellCommand(`ELECTRON_RUN_AS_NODE=1 exec ${this.buildCommand(cliEntry, args)}`)
       : this.buildDirectSpawn(cliEntry, args)
 
+    const detached = process.platform !== "win32"
     const child = spawn(spawnDetails.command, spawnDetails.args, {
       cwd: process.cwd(),
       stdio: ["ignore", "pipe", "pipe"],
       env,
       shell: false,
+      detached,
     })
 
     console.info(`[cli] spawn command: ${spawnDetails.command} ${spawnDetails.args.join(" ")}`)
@@ -175,12 +179,89 @@ export class CliProcessManager extends EventEmitter {
       return
     }
 
+    this.requestedStop = true
+
+    const pid = child.pid
+    if (!pid) {
+      this.child = undefined
+      this.updateStatus({ state: "stopped" })
+      return
+    }
+
+    const isAlreadyExited = () => child.exitCode !== null || child.signalCode !== null
+
+    const tryKillPosixGroup = (signal: NodeJS.Signals) => {
+      try {
+        // Negative PID targets the process group (POSIX).
+        process.kill(-pid, signal)
+        return true
+      } catch (error) {
+        const err = error as NodeJS.ErrnoException
+        if (err?.code === "ESRCH") {
+          return true
+        }
+        return false
+      }
+    }
+
+    const tryKillSinglePid = (signal: NodeJS.Signals) => {
+      try {
+        process.kill(pid, signal)
+        return true
+      } catch (error) {
+        const err = error as NodeJS.ErrnoException
+        if (err?.code === "ESRCH") {
+          return true
+        }
+        return false
+      }
+    }
+
+    const tryTaskkill = (force: boolean) => {
+      const args = ["/PID", String(pid), "/T"]
+      if (force) {
+        args.push("/F")
+      }
+
+      try {
+        const result = spawnSync("taskkill", args, { encoding: "utf8" })
+        const exitCode = result.status
+        if (exitCode === 0) {
+          return true
+        }
+
+        // If the PID is already gone, treat it as success.
+        const stderr = (result.stderr ?? "").toString().toLowerCase()
+        const stdout = (result.stdout ?? "").toString().toLowerCase()
+        const combined = `${stdout}\n${stderr}`
+        if (combined.includes("not found") || combined.includes("no running instance")) {
+          return true
+        }
+        return false
+      } catch {
+        return false
+      }
+    }
+
+    const sendStopSignal = (signal: NodeJS.Signals) => {
+      if (process.platform === "win32") {
+        tryTaskkill(signal === "SIGKILL")
+        return
+      }
+
+      // Prefer process-group signaling so wrapper launchers (shell/tsx) don't outlive Electron.
+      const groupOk = tryKillPosixGroup(signal)
+      if (!groupOk) {
+        tryKillSinglePid(signal)
+      }
+    }
+
     return new Promise((resolve) => {
       const killTimeout = setTimeout(() => {
         console.warn(
           `[cli] stop timed out after 30000ms; sending SIGKILL (pid=${child.pid ?? "unknown"})`,
         )
-        child.kill("SIGKILL")
+        sendStopSignal("SIGKILL")
       }, 30000)
 
       child.on("exit", () => {
@@ -191,7 +272,15 @@ export class CliProcessManager extends EventEmitter {
         resolve()
       })
 
-      child.kill("SIGTERM")
+      if (isAlreadyExited()) {
+        clearTimeout(killTimeout)
+        this.child = undefined
+        this.updateStatus({ state: "stopped" })
+        resolve()
+        return
+      }
+
+      sendStopSignal("SIGTERM")
     })
   }
 
@@ -205,7 +294,16 @@ export class CliProcessManager extends EventEmitter {
 
   private handleTimeout() {
     if (this.child) {
-      this.child.kill("SIGKILL")
+      const pid = this.child.pid
+      if (pid && process.platform !== "win32") {
+        try {
+          process.kill(-pid, "SIGKILL")
+        } catch {
+          this.child.kill("SIGKILL")
+        }
+      } else {
+        this.child.kill("SIGKILL")
+      }
       this.child = undefined
     }
     this.updateStatus({ state: "error", error: "CLI did not start in time" })