diff --git a/packages/autonav/src/cli/nav-chat.ts b/packages/autonav/src/cli/nav-chat.ts
index ab32995..399c37b 100644
--- a/packages/autonav/src/cli/nav-chat.ts
+++ b/packages/autonav/src/cli/nav-chat.ts
@@ -133,6 +133,7 @@ export async function run(args: string[]): Promise<void> {
     instructionsPath?: string;
     relatedNavigators?: Array<{ name: string; description?: string }>;
     sandbox?: { chat?: { enabled: boolean } };
+    harness?: { type?: string; model?: string };
   };
   let configContent: string;
   try {
@@ -219,6 +220,7 @@ export async function run(args: string[]): Promise<void> {
       mcpServers: Object.keys(mcpServers).length > 0 ? mcpServers : undefined,
       sandboxEnabled: chatSandboxEnabled,
       configJson: configContent,
+      model: config.harness?.model,
     });
 
     console.log("\n👋 Conversation ended.\n");
diff --git a/packages/autonav/src/conversation/index.ts b/packages/autonav/src/conversation/index.ts
index de93580..ba6bbf4 100644
--- a/packages/autonav/src/conversation/index.ts
+++ b/packages/autonav/src/conversation/index.ts
@@ -37,6 +37,8 @@ export interface ConversationOptions {
   sandboxEnabled?: boolean;
   /** Raw config.json content for config-aware prompts */
   configJson?: string;
+  /** Model override for the harness. When undefined, the harness uses its own default. */
+  model?: string;
 }
 
 /**