diff --git a/src/resources/extensions/ollama/index.ts b/src/resources/extensions/ollama/index.ts
index 550771232..22102c231 100644
--- a/src/resources/extensions/ollama/index.ts
+++ b/src/resources/extensions/ollama/index.ts
@@ -61,8 +61,13 @@ async function probeAndRegister(pi: ExtensionAPI): Promise<boolean> {
 
 	const baseUrl = client.getOllamaHost();
 
+	// Use authMode "apiKey" with a dummy key (#3440).
+	// authMode "none" requires a custom streamSimple handler, but Ollama uses
+	// the standard OpenAI-compatible streaming endpoint. Ollama ignores the
+	// Authorization header so the dummy key is harmless.
 	pi.registerProvider("ollama", {
-		authMode: "none",
+		authMode: "apiKey",
+		apiKey: "ollama",
 		baseUrl,
 		api: "ollama-chat",
 		streamSimple: streamOllamaChat,
diff --git a/src/resources/extensions/ollama/ollama-auth-mode.test.ts b/src/resources/extensions/ollama/ollama-auth-mode.test.ts
new file mode 100644
index 000000000..e74f2e76c
--- /dev/null
+++ b/src/resources/extensions/ollama/ollama-auth-mode.test.ts
@@ -0,0 +1,20 @@
+/**
+ * Regression test for #3440: Ollama extension must register with
+ * authMode "apiKey" (not "none") to avoid streamSimple requirement.
+ */
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { join, dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+test("Ollama registers with authMode apiKey, not none (#3440)", () => {
+  const src = readFileSync(join(__dirname, "index.ts"), "utf-8");
+  // Find the registerProvider call
+  const registerBlock = src.slice(src.indexOf("pi.registerProvider(\"ollama\""));
+  const authLine = registerBlock.match(/authMode:\s*"(\w+)"/);
+  assert.ok(authLine, "registerProvider must specify authMode");
+  assert.equal(authLine![1], "apiKey", "authMode must be apiKey, not none");
+});