diff --git a/packages/cli-v3/src/commands/dev.ts b/packages/cli-v3/src/commands/dev.ts
index c7b25110f2..7a9726dc56 100644
--- a/packages/cli-v3/src/commands/dev.ts
+++ b/packages/cli-v3/src/commands/dev.ts
@@ -18,6 +18,7 @@ const DevCommandOptions = CommonCommandOptions.extend({
   projectRef: z.string().optional(),
   skipUpdateCheck: z.boolean().default(false),
   envFile: z.string().optional(),
+  keepTmpFiles: z.boolean().default(false),
 });
 
 export type DevCommandOptions = z.infer<typeof DevCommandOptions>;
@@ -38,6 +39,10 @@ export function configureDevCommand(program: Command) {
       )
       .option("--debug-otel", "Enable OpenTelemetry debugging")
       .option("--skip-update-check", "Skip checking for @trigger.dev package updates")
+      .option(
+        "--keep-tmp-files",
+        "Keep temporary files after the dev session ends, helpful for debugging"
+      )
   ).action(async (options) => {
     wrapCommandAction("dev", DevCommandOptions, options, async (opts) => {
       await devCommand(opts);
@@ -151,6 +156,7 @@ async function startDev(options: StartDevOptions) {
         initialMode: "local",
         dashboardUrl: options.login.dashboardUrl,
         showInteractiveDevSession: true,
+        keepTmpFiles: options.keepTmpFiles,
       });
     }
 
diff --git a/packages/cli-v3/src/dev/backgroundWorker.ts b/packages/cli-v3/src/dev/backgroundWorker.ts
index 1a617f0824..ad4239bde5 100644
--- a/packages/cli-v3/src/dev/backgroundWorker.ts
+++ b/packages/cli-v3/src/dev/backgroundWorker.ts
@@ -111,6 +111,7 @@ export class BackgroundWorkerCoordinator {
     }
 
     this._backgroundWorkers.set(worker.serverWorker.id, worker);
+
     this.onWorkerRegistered.post({
       worker,
       id: worker.serverWorker.id,
@@ -126,14 +127,6 @@ export class BackgroundWorkerCoordinator {
     });
   }
 
-  close() {
-    for (const worker of this._backgroundWorkers.values()) {
-      worker.close();
-    }
-
-    this._backgroundWorkers.clear();
-  }
-
   async executeTaskRun(id: string, payload: TaskRunExecutionPayload, messageId: string) {
     const worker = this._backgroundWorkers.get(id);
 
@@ -186,11 +179,11 @@ export class BackgroundWorkerCoordinator {
 export type BackgroundWorkerOptions = {
   env: Record<string, string>;
   cwd: string;
+  stop: () => void;
 };
 
 export class BackgroundWorker {
   public onTaskRunHeartbeat: Evt<string> = new Evt();
-  private _onClose: Evt<void> = new Evt();
 
   public deprecated: boolean = false;
   public manifest: WorkerManifest | undefined;
@@ -199,33 +192,27 @@ export class BackgroundWorker {
   _taskRunProcesses: Map<string, TaskRunProcess> = new Map();
   private _taskRunProcessesBeingKilled: Map<number, TaskRunProcess> = new Map();
 
-  private _closed: boolean = false;
-
   constructor(
     public build: BuildManifest,
     public params: BackgroundWorkerOptions
   ) {}
 
   deprecate() {
-    this.deprecated = true;
-  }
-
-  close() {
-    if (this._closed) {
+    if (this.deprecated) {
       return;
     }
 
-    this._closed = true;
+    this.deprecated = true;
 
-    this.onTaskRunHeartbeat.detach();
+    this.#tryStopWorker();
+  }
 
-    // We need to close all the task run processes
-    for (const taskRunProcess of this._taskRunProcesses.values()) {
-      taskRunProcess.cleanup(true);
-    }
+  #tryStopWorker() {
+    if (this.deprecated && this._taskRunProcesses.size === 0) {
+      logger.debug("Worker deprecated, stopping", { outputPath: this.build.outputPath });
 
-    // Delete worker files
-    this._onClose.post();
+      this.params.stop();
+    }
   }
 
   get inProgressRuns(): Array<string> {
@@ -301,8 +288,6 @@ export class BackgroundWorker {
       throw new Error("Worker not initialized");
     }
 
-    this._closed = false;
-
     logger.debug(this.#prefixedMessage(payload, "killing current task run process before attempt"));
 
     await this.#killCurrentTaskRunProcessBeforeAttempt(payload.execution.run.id);
@@ -332,6 +317,8 @@ export class BackgroundWorker {
       // Only delete the task run process if the pid matches
       if (taskRunProcess?.pid === pid) {
         this._taskRunProcesses.delete(payload.execution.run.id);
+
+        this.#tryStopWorker();
       }
 
       if (pid) {
@@ -435,10 +422,6 @@ export class BackgroundWorker {
     payload: TaskRunExecutionPayload,
     messageId: string
   ): Promise<TaskRunExecutionResult> {
-    if (this._closed) {
-      throw new Error("Worker is closed");
-    }
-
     if (!this.manifest) {
       throw new Error("Worker not initialized");
     }
diff --git a/packages/cli-v3/src/dev/devSession.ts b/packages/cli-v3/src/dev/devSession.ts
index 2de079ffbc..8d80b30d7f 100644
--- a/packages/cli-v3/src/dev/devSession.ts
+++ b/packages/cli-v3/src/dev/devSession.ts
@@ -23,10 +23,11 @@ import { type DevCommandOptions } from "../commands/dev.js";
 import { eventBus } from "../utilities/eventBus.js";
 import { logger } from "../utilities/logger.js";
 import { resolveFileSources } from "../utilities/sourceFiles.js";
-import { EphemeralDirectory, getTmpDir } from "../utilities/tempDirectories.js";
+import { clearTmpDirs, EphemeralDirectory, getTmpDir } from "../utilities/tempDirectories.js";
 import { VERSION } from "../version.js";
 import { startDevOutput } from "./devOutput.js";
 import { startWorkerRuntime } from "./workerRuntime.js";
+import { existsSync, mkdirSync, rmSync } from "node:fs";
 
 export type DevSessionOptions = {
   name: string | undefined;
@@ -37,6 +38,7 @@ export type DevSessionOptions = {
   rawArgs: DevCommandOptions;
   client: CliApiClient;
   onErr?: (error: Error) => void;
+  keepTmpFiles: boolean;
 };
 
 export type DevSessionInstance = {
@@ -49,8 +51,10 @@ export async function startDevSession({
   rawArgs,
   client,
   dashboardUrl,
+  keepTmpFiles,
 }: DevSessionOptions): Promise<DevSessionInstance> {
-  const destination = getTmpDir(rawConfig.workingDir, "build");
+  clearTmpDirs(rawConfig.workingDir);
+  const destination = getTmpDir(rawConfig.workingDir, "build", keepTmpFiles);
 
   const runtime = await startWorkerRuntime({
     name,
@@ -96,7 +100,7 @@ export async function startDevSession({
     try {
       logger.debug("Updated bundle", { bundle, buildManifest });
 
-      await runtime.initializeWorker(buildManifest);
+      await runtime.initializeWorker(buildManifest, workerDir?.remove ?? (() => {}));
     } catch (error) {
       if (error instanceof Error) {
         eventBus.emit("backgroundWorkerIndexingError", buildManifest, error);
@@ -124,6 +128,14 @@ export async function startDevSession({
         if (bundled) {
           eventBus.emit("rebuildStarted", "dev");
         }
+
+        const outdir = b.initialOptions.outdir;
+        if (outdir && existsSync(outdir)) {
+          logger.debug("Removing outdir", { outdir });
+
+          rmSync(outdir, { recursive: true, force: true });
+          mkdirSync(outdir, { recursive: true });
+        }
       });
       b.onEnd(async (result: esbuild.BuildResult) => {
         const errors = result.errors;
@@ -141,7 +153,7 @@ export async function startDevSession({
           // First bundle, no need to update bundle
           bundled = true;
         } else {
-          const workerDir = getTmpDir(rawConfig.workingDir, "build");
+          const workerDir = getTmpDir(rawConfig.workingDir, "build", keepTmpFiles);
 
           await updateBuild(result, workerDir);
         }
diff --git a/packages/cli-v3/src/dev/workerRuntime.ts b/packages/cli-v3/src/dev/workerRuntime.ts
index a1801a68c3..1f816d12f2 100644
--- a/packages/cli-v3/src/dev/workerRuntime.ts
+++ b/packages/cli-v3/src/dev/workerRuntime.ts
@@ -30,7 +30,7 @@ import { VERSION } from "../version.js";
 
 export interface WorkerRuntime {
   shutdown(): Promise<void>;
-  initializeWorker(manifest: BuildManifest): Promise<void>;
+  initializeWorker(manifest: BuildManifest, stop: () => void): Promise<void>;
 }
 
 export type WorkerRuntimeOptions = {
@@ -167,9 +167,10 @@ class DevWorkerRuntime implements WorkerRuntime {
     }
   }
 
-  async initializeWorker(manifest: BuildManifest, options?: { cwd?: string }): Promise<void> {
+  async initializeWorker(manifest: BuildManifest, stop: () => void): Promise<void> {
     if (this.lastBuild && this.lastBuild.contentHash === manifest.contentHash) {
       eventBus.emit("workerSkipped");
+      stop();
       return;
     }
 
@@ -178,11 +179,13 @@ class DevWorkerRuntime implements WorkerRuntime {
     const backgroundWorker = new BackgroundWorker(manifest, {
       env,
       cwd: this.options.config.workingDir,
+      stop,
     });
 
     await backgroundWorker.initialize();
 
     if (!backgroundWorker.manifest) {
+      stop();
       throw new Error("Could not initialize worker");
     }
 
@@ -190,6 +193,7 @@ class DevWorkerRuntime implements WorkerRuntime {
 
     if (issues.length > 0) {
       issues.forEach((issue) => logger.error(issue));
+      stop();
       return;
     }
 
@@ -213,6 +217,7 @@ class DevWorkerRuntime implements WorkerRuntime {
     );
 
     if (!backgroundWorkerRecord.success) {
+      stop();
       throw new Error(backgroundWorkerRecord.error);
     }
 
diff --git a/packages/cli-v3/src/utilities/tempDirectories.ts b/packages/cli-v3/src/utilities/tempDirectories.ts
index 3dc33fff31..7ab28fb11e 100644
--- a/packages/cli-v3/src/utilities/tempDirectories.ts
+++ b/packages/cli-v3/src/utilities/tempDirectories.ts
@@ -30,8 +30,14 @@ export function getTmpDir(
   const tmpPrefix = path.join(tmpRoot, `${prefix}-`);
   const tmpDir = fs.realpathSync(fs.mkdtempSync(tmpPrefix));
 
-  let removeDir = keep ? () => {} : () => fs.rmSync(tmpDir, { recursive: true, force: true });
-  let removeExitListener = keep ? () => {} : onExit(removeDir);
+  const removeDir = () => {
+    try {
+      return fs.rmSync(tmpDir, { recursive: true, force: true });
+    } catch (e) {
+      // This sometimes fails on Windows with EBUSY
+    }
+  };
+  const removeExitListener = keep ? () => {} : onExit(removeDir);
 
   return {
     path: tmpDir,
@@ -41,3 +47,14 @@ export function getTmpDir(
     },
   };
 }
+
+export function clearTmpDirs(projectRoot: string | undefined) {
+  projectRoot ??= process.cwd();
+  const tmpRoot = path.join(projectRoot, ".trigger", "tmp");
+
+  try {
+    fs.rmSync(tmpRoot, { recursive: true, force: true });
+  } catch (e) {
+    // This sometimes fails on Windows with EBUSY
+  }
+}