diff --git a/sdk/typescript/README.md b/sdk/typescript/README.md
index 19accb0b30..b74fd44ba3 100644
--- a/sdk/typescript/README.md
+++ b/sdk/typescript/README.md
@@ -51,3 +51,21 @@ const result = await thread.run("Implement the fix");
 
 console.log(result);
 ```
+
+### Working directory
+
+By default, Codex will run in the current working directory. You can change the working directory by passing the `workingDirectory` option to the when creating a thread.
+
+```typescript
+const thread = codex.startThread({
+  workingDirectory: "/path/to/working/directory",
+});
+```
+
+To avoid unrecoverable errors, Codex requires the working directory to be a git repository. You can skip the git repository check by passing the `skipGitRepoCheck` option to the when creating a thread.
+
+```typescript
+const thread = codex.startThread({
+  skipGitRepoCheck: true,
+});
+```
diff --git a/sdk/typescript/src/codex.ts b/sdk/typescript/src/codex.ts
index 8f87122839..84376e677e 100644
--- a/sdk/typescript/src/codex.ts
+++ b/sdk/typescript/src/codex.ts
@@ -1,6 +1,7 @@
 import { CodexOptions } from "./codexOptions";
 import { CodexExec } from "./exec";
 import { Thread } from "./thread";
+import { ThreadOptions } from "./threadOptions";
 
 /**
  * Codex is the main class for interacting with the Codex agent.
@@ -20,8 +21,8 @@ export class Codex {
    * Starts a new conversation with an agent.
    * @returns A new thread instance.
    */
-  startThread(): Thread {
-    return new Thread(this.exec, this.options);
+  startThread(options: ThreadOptions = {}): Thread {
+    return new Thread(this.exec, this.options, options);
   }
 
   /**
@@ -31,7 +32,7 @@ export class Codex {
    * @param id The id of the thread to resume.
    * @returns A new thread instance.
    */
-  resumeThread(id: string): Thread {
-    return new Thread(this.exec, this.options, id);
+  resumeThread(id: string, options: ThreadOptions = {}): Thread {
+    return new Thread(this.exec, this.options, options, id);
   }
 }
diff --git a/sdk/typescript/src/exec.ts b/sdk/typescript/src/exec.ts
index cdb1982f0d..91ce763909 100644
--- a/sdk/typescript/src/exec.ts
+++ b/sdk/typescript/src/exec.ts
@@ -2,7 +2,7 @@ import { spawn } from "node:child_process";
 
 import readline from "node:readline";
 
-import { SandboxMode } from "./turnOptions";
+import { SandboxMode } from "./threadOptions";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
 
diff --git a/sdk/typescript/src/index.ts b/sdk/typescript/src/index.ts
index f2f84d153c..b759b3c68f 100644
--- a/sdk/typescript/src/index.ts
+++ b/sdk/typescript/src/index.ts
@@ -29,4 +29,4 @@ export { Codex } from "./codex";
 
 export type { CodexOptions } from "./codexOptions";
 
-export type { TurnOptions, ApprovalMode, SandboxMode } from "./turnOptions";
+export type { ThreadOptions as TheadOptions, ApprovalMode, SandboxMode } from "./threadOptions";
diff --git a/sdk/typescript/src/thread.ts b/sdk/typescript/src/thread.ts
index 7ec710217c..fe32a27136 100644
--- a/sdk/typescript/src/thread.ts
+++ b/sdk/typescript/src/thread.ts
@@ -2,7 +2,7 @@ import { CodexOptions } from "./codexOptions";
 import { ThreadEvent } from "./events";
 import { CodexExec } from "./exec";
 import { ThreadItem } from "./items";
-import { TurnOptions } from "./turnOptions";
+import { ThreadOptions } from "./threadOptions";
 
 /** Completed turn. */
 export type Turn = {
@@ -29,27 +29,33 @@ export class Thread {
   private _exec: CodexExec;
   private _options: CodexOptions;
   private _id: string | null;
+  private _threadOptions: ThreadOptions;
 
   /** Returns the ID of the thread. Populated after the first turn starts. */
   public get id(): string | null {
     return this._id;
   }
 
-  constructor(exec: CodexExec, options: CodexOptions, id: string | null = null) {
+  /* @internal */
+  constructor(
+    exec: CodexExec,
+    options: CodexOptions,
+    threadOptions: ThreadOptions,
+    id: string | null = null,
+  ) {
     this._exec = exec;
     this._options = options;
     this._id = id;
+    this._threadOptions = threadOptions;
   }
 
   /** Provides the input to the agent and streams events as they are produced during the turn. */
-  async runStreamed(input: string, options?: TurnOptions): Promise<StreamedTurn> {
-    return { events: this.runStreamedInternal(input, options) };
+  async runStreamed(input: string): Promise<StreamedTurn> {
+    return { events: this.runStreamedInternal(input) };
   }
 
-  private async *runStreamedInternal(
-    input: string,
-    options?: TurnOptions,
-  ): AsyncGenerator<ThreadEvent> {
+  private async *runStreamedInternal(input: string): AsyncGenerator<ThreadEvent> {
+    const options = this._threadOptions;
     const generator = this._exec.run({
       input,
       baseUrl: this._options.baseUrl,
@@ -75,8 +81,8 @@ export class Thread {
   }
 
   /** Provides the input to the agent and returns the completed turn. */
-  async run(input: string, options?: TurnOptions): Promise<Turn> {
-    const generator = this.runStreamedInternal(input, options);
+  async run(input: string): Promise<Turn> {
+    const generator = this.runStreamedInternal(input);
     const items: ThreadItem[] = [];
     let finalResponse: string = "";
     for await (const event of generator) {
diff --git a/sdk/typescript/src/turnOptions.ts b/sdk/typescript/src/threadOptions.ts
similarity index 90%
rename from sdk/typescript/src/turnOptions.ts
rename to sdk/typescript/src/threadOptions.ts
index ce56d7b2c6..7f01488d23 100644
--- a/sdk/typescript/src/turnOptions.ts
+++ b/sdk/typescript/src/threadOptions.ts
@@ -2,7 +2,7 @@ export type ApprovalMode = "never" | "on-request" | "on-failure" | "untrusted";
 
 export type SandboxMode = "read-only" | "workspace-write" | "danger-full-access";
 
-export type TurnOptions = {
+export type ThreadOptions = {
   model?: string;
   sandboxMode?: SandboxMode;
   workingDirectory?: string;
diff --git a/sdk/typescript/tests/codexExecSpy.ts b/sdk/typescript/tests/codexExecSpy.ts
index 3715f71e0b..bf7cbd6cc8 100644
--- a/sdk/typescript/tests/codexExecSpy.ts
+++ b/sdk/typescript/tests/codexExecSpy.ts
@@ -5,7 +5,8 @@ jest.mock("node:child_process", () => {
   return { ...actual, spawn: jest.fn(actual.spawn) };
 });
 
-const actualChildProcess = jest.requireActual<typeof import("node:child_process")>("node:child_process");
+const actualChildProcess =
+  jest.requireActual<typeof import("node:child_process")>("node:child_process");
 const spawnMock = child_process.spawn as jest.MockedFunction<typeof actualChildProcess.spawn>;
 
 export function codexExecSpy(): { args: string[][]; restore: () => void } {
diff --git a/sdk/typescript/tests/run.test.ts b/sdk/typescript/tests/run.test.ts
index 2f15237f4f..357d8cd0db 100644
--- a/sdk/typescript/tests/run.test.ts
+++ b/sdk/typescript/tests/run.test.ts
@@ -109,9 +109,7 @@ describe("Codex", () => {
 
       const thread = client.startThread();
       await thread.run("first input");
-      await thread.run("second input", {
-        model: "gpt-test-1",
-      });
+      await thread.run("second input");
 
       // Check second request continues the same thread
       expect(requests.length).toBeGreaterThanOrEqual(2);
@@ -119,7 +117,7 @@ describe("Codex", () => {
       expect(secondRequest).toBeDefined();
       const payload = secondRequest!.json;
 
-      expect(payload.model).toBe("gpt-test-1");
+      expect(payload.input.at(-1)!.content![0]!.text).toBe("second input");
       const assistantEntry = payload.input.find(
         (entry: { role: string }) => entry.role === "assistant",
       );
@@ -197,11 +195,11 @@ describe("Codex", () => {
     try {
       const client = new Codex({ codexPathOverride: codexExecPath, baseUrl: url, apiKey: "test" });
 
-      const thread = client.startThread();
-      await thread.run("apply options", {
+      const thread = client.startThread({
         model: "gpt-test-1",
         sandboxMode: "workspace-write",
       });
+      await thread.run("apply options");
 
       const payload = requests[0];
       expect(payload).toBeDefined();
@@ -240,11 +238,11 @@ describe("Codex", () => {
         apiKey: "test",
       });
 
-      const thread = client.startThread();
-      await thread.run("use custom working directory", {
+      const thread = client.startThread({
         workingDirectory,
         skipGitRepoCheck: true,
       });
+      await thread.run("use custom working directory");
 
       const commandArgs = spawnArgs[0];
       expectPair(commandArgs, ["--cd", workingDirectory]);
@@ -274,12 +272,12 @@ describe("Codex", () => {
         apiKey: "test",
       });
 
-      const thread = client.startThread();
-      await expect(
-        thread.run("use custom working directory", {
-          workingDirectory,
-        }),
-      ).rejects.toThrow(/Not inside a trusted directory/);
+      const thread = client.startThread({
+        workingDirectory,
+      });
+      await expect(thread.run("use custom working directory")).rejects.toThrow(
+        /Not inside a trusted directory/,
+      );
     } finally {
       await close();
     }