diff --git a/package.json b/package.json
index 8dcbeb7..d906cb6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ode",
-  "version": "0.1.19",
+  "version": "0.1.20",
   "description": "Coding anywhere with your coding agents connected",
   "module": "packages/core/index.ts",
   "type": "module",
diff --git a/packages/agents/codex/client.ts b/packages/agents/codex/client.ts
index bccfd75..2dd033f 100644
--- a/packages/agents/codex/client.ts
+++ b/packages/agents/codex/client.ts
@@ -40,7 +40,7 @@ type CodexJsonEvent = {
 function getCodexModel(options?: OpenCodeOptions): string | undefined {
   const configured = options?.model?.modelID?.trim();
   if (configured) return configured;
-  return DEFAULT_CODEX_MODEL;
+  return undefined;
 }
 
 type CodexModelCatalog = {
diff --git a/packages/agents/test/cli-command.test.ts b/packages/agents/test/cli-command.test.ts
index 309b68a..cd5f32b 100644
--- a/packages/agents/test/cli-command.test.ts
+++ b/packages/agents/test/cli-command.test.ts
@@ -139,6 +139,18 @@ describe("agent cli command formatting", () => {
     expect(command).toContain("'plan this change'");
   });
 
+  it("omits the Codex model flag when no model is configured", () => {
+    const args = buildCodexCommandArgs({
+      sessionId: "session-3",
+      prompt: "hello from codex",
+    });
+    const command = buildCodexCommand(args);
+
+    expect(command).not.toContain("--model");
+    expect(command).toContain("session-3");
+    expect(command).toContain("'hello from codex'");
+  });
+
   it("builds the Kimi print command", () => {
     const args = buildKimiCommandArgs({
       sessionId: "session-4",
diff --git a/packages/core/runtime/message-options.ts b/packages/core/runtime/message-options.ts
index ada0f87..8143460 100644
--- a/packages/core/runtime/message-options.ts
+++ b/packages/core/runtime/message-options.ts
@@ -1,4 +1,4 @@
-import { DEFAULT_CODEX_MODEL, getChannelModel } from "@/config";
+import { getChannelModel } from "@/config";
 import type { OpenCodeOptions } from "@/agents";
 
 type ProviderId = "opencode" | "claudecode" | "codex" | "kimi" | "kiro" | "kilo" | "qwen" | "goose" | "gemini";
@@ -24,7 +24,7 @@ export function buildMessageOptions(params: {
 
   const channelModel = getChannelModel(channelId)?.trim();
   const codexModel = providerId === "codex"
-    ? (channelModel && channelModel.length > 0 ? channelModel : DEFAULT_CODEX_MODEL)
+    ? (channelModel && channelModel.length > 0 ? channelModel : undefined)
     : undefined;
   const kiloModel = providerId === "kilo" ? toKiloModel(channelModel) : undefined;
 
diff --git a/packages/ims/shared/settings-domain.ts b/packages/ims/shared/settings-domain.ts
index a898f3e..7222667 100644
--- a/packages/ims/shared/settings-domain.ts
+++ b/packages/ims/shared/settings-domain.ts
@@ -66,9 +66,9 @@ export function describeChannelSettingsIssues(channelId: string): string[] {
         ? lists.codex
         : lists.kilo;
     const modelSet = new Set(models.map(normalizeModel));
-    if (!model) {
+    if (!model && provider !== "codex") {
       issues.push("Model not configured.");
-    } else if (!modelSet.has(normalizeModel(model))) {
+    } else if (model && !modelSet.has(normalizeModel(model))) {
       issues.push(`Model not available in configured ${getAgentProviderLabel(provider)} models.`);
     }
   }
diff --git a/packages/ims/slack/commands.ts b/packages/ims/slack/commands.ts
index 42405c2..249c6f4 100644
--- a/packages/ims/slack/commands.ts
+++ b/packages/ims/slack/commands.ts
@@ -291,7 +291,6 @@ function buildSettingsModal(params: {
   blocks.push({
     type: "input" as const,
     block_id: WORKING_DIR_BLOCK,
-    optional: true,
     label: { type: "plain_text" as const, text: "Working Directory" },
     element: {
       type: "plain_text_input" as const,
@@ -700,6 +699,10 @@ export function setupInteractiveHandlers(): void {
       }
     }
 
+    if (!workingDirectory.trim()) {
+      errors[WORKING_DIR_BLOCK] = "Enter a working directory.";
+    }
+
     if (Object.keys(errors).length > 0) {
       await ack({ response_action: "errors", errors });
       return;