add: responses api support for azure (#1321)

- Use Responses API for Azure provider endpoints
- Added a unit test to catch regression on the change from
`/chat/completions` to `/responses`
- Updated the default AOAI api version from `2025-03-01-preview` to
`2025-04-01-preview` to avoid user/400 errors due to missing summary
support in the March API version.
- Changes have been tested locally on AOAI endpoints

README.md

@@ -469,7 +469,7 @@ export OPENAI_API_KEY="your-api-key-here"
 
 # Azure OpenAI
 export AZURE_OPENAI_API_KEY="your-azure-api-key-here"
-export AZURE_OPENAI_API_VERSION="2025-03-01-preview" (Optional)
+export AZURE_OPENAI_API_VERSION="2025-04-01-preview" (Optional)
 
 # OpenRouter
 export OPENROUTER_API_KEY="your-openrouter-key-here"

codex-cli/src/utils/agent/agent-loop.ts

@@ -800,7 +800,8 @@ export class AgentLoop {
 
             const responseCall =
               !this.config.provider ||
-              this.config.provider?.toLowerCase() === "openai"
+              this.config.provider?.toLowerCase() === "openai" ||
+              this.config.provider?.toLowerCase() === "azure"
                 ? (params: ResponseCreateParams) =>
                     this.oai.responses.create(params)
                 : (params: ResponseCreateParams) =>
@@ -1188,7 +1189,8 @@ export class AgentLoop {
 
               const responseCall =
                 !this.config.provider ||
-                this.config.provider?.toLowerCase() === "openai"
+                this.config.provider?.toLowerCase() === "openai" ||
+                this.config.provider?.toLowerCase() === "azure"
                   ? (params: ResponseCreateParams) =>
                       this.oai.responses.create(params)
                   : (params: ResponseCreateParams) =>

codex-cli/src/utils/config.ts

@@ -69,7 +69,7 @@ export const OPENAI_BASE_URL = process.env["OPENAI_BASE_URL"] || "";
 export let OPENAI_API_KEY = process.env["OPENAI_API_KEY"] || "";
 
 export const AZURE_OPENAI_API_VERSION =
-  process.env["AZURE_OPENAI_API_VERSION"] || "2025-03-01-preview";
+  process.env["AZURE_OPENAI_API_VERSION"] || "2025-04-01-preview";
 
 export const DEFAULT_REASONING_EFFORT = "high";
 export const OPENAI_ORGANIZATION = process.env["OPENAI_ORGANIZATION"] || "";

codex-cli/tests/agent-azure-responses-endpoint.test.ts

@@ -0,0 +1,107 @@
+/**
+ * tests/agent-azure-responses-endpoint.test.ts
+ *
+ * Verifies that AgentLoop calls the `/responses` endpoint when provider is set to Azure.
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+// Fake stream that yields a completed response event
+class FakeStream {
+  async *[Symbol.asyncIterator]() {
+    yield {
+      type: "response.completed",
+      response: { id: "azure_resp", status: "completed", output: [] },
+    } as any;
+  }
+}
+
+let lastCreateParams: any = null;
+
+vi.mock("openai", () => {
+  class FakeDefaultClient {
+    public responses = {
+      create: async (params: any) => {
+        lastCreateParams = params;
+        return new FakeStream();
+      },
+    };
+  }
+  class FakeAzureClient {
+    public responses = {
+      create: async (params: any) => {
+        lastCreateParams = params;
+        return new FakeStream();
+      },
+    };
+  }
+  class APIConnectionTimeoutError extends Error {}
+  return {
+    __esModule: true,
+    default: FakeDefaultClient,
+    AzureOpenAI: FakeAzureClient,
+    APIConnectionTimeoutError,
+  };
+});
+
+// Stub approvals to bypass command approval logic
+vi.mock("../src/approvals.js", () => ({
+  __esModule: true,
+  alwaysApprovedCommands: new Set<string>(),
+  canAutoApprove: () => ({ type: "auto-approve", runInSandbox: false }),
+  isSafeCommand: () => null,
+}));
+
+// Stub format-command to avoid formatting side effects
+vi.mock("../src/format-command.js", () => ({
+  __esModule: true,
+  formatCommandForDisplay: (cmd: Array<string>) => cmd.join(" "),
+}));
+
+// Stub internal logging to keep output clean
+vi.mock("../src/utils/agent/log.js", () => ({
+  __esModule: true,
+  log: () => {},
+  isLoggingEnabled: () => false,
+}));
+
+import { AgentLoop } from "../src/utils/agent/agent-loop.js";
+
+describe("AgentLoop Azure provider responses endpoint", () => {
+  beforeEach(() => {
+    lastCreateParams = null;
+  });
+
+  it("calls the /responses endpoint when provider is azure", async () => {
+    const cfg: any = {
+      model: "test-model",
+      provider: "azure",
+      instructions: "",
+      disableResponseStorage: false,
+      notify: false,
+    };
+    const loop = new AgentLoop({
+      additionalWritableRoots: [],
+      model: cfg.model,
+      config: cfg,
+      instructions: cfg.instructions,
+      approvalPolicy: { mode: "suggest" } as any,
+      onItem: () => {},
+      onLoading: () => {},
+      getCommandConfirmation: async () => ({ review: "yes" }) as any,
+      onLastResponseId: () => {},
+    });
+
+    await loop.run([
+      {
+        type: "message",
+        role: "user",
+        content: [{ type: "input_text", text: "hello" }],
+      },
+    ]);
+
+    expect(lastCreateParams).not.toBeNull();
+    expect(lastCreateParams.model).toBe(cfg.model);
+    expect(Array.isArray(lastCreateParams.input)).toBe(true);
+  });
+});