diff --git a/src/__tests__/parseOllamaHost.test.ts b/src/__tests__/parseOllamaHost.test.ts
new file mode 100644
index 0000000..bd3c185
--- /dev/null
+++ b/src/__tests__/parseOllamaHost.test.ts
@@ -0,0 +1,147 @@
+import { parseOllamaHost } from "@/ipc/handlers/local_model_ollama_handler";
+import { describe, it, expect } from "vitest";
+
+describe("parseOllamaHost", () => {
+  it("should return default URL when no host is provided", () => {
+    const result = parseOllamaHost();
+    expect(result).toBe("http://localhost:11434");
+  });
+
+  it("should return default URL when host is undefined", () => {
+    const result = parseOllamaHost(undefined);
+    expect(result).toBe("http://localhost:11434");
+  });
+
+  it("should return default URL when host is empty string", () => {
+    const result = parseOllamaHost("");
+    expect(result).toBe("http://localhost:11434");
+  });
+
+  describe("full URLs with protocol", () => {
+    it("should return http URLs as-is", () => {
+      const input = "http://localhost:11434";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://localhost:11434");
+    });
+
+    it("should return https URLs as-is", () => {
+      const input = "https://example.com:11434";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("https://example.com:11434");
+    });
+
+    it("should return http URLs with custom ports as-is", () => {
+      const input = "http://192.168.1.100:8080";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://192.168.1.100:8080");
+    });
+
+    it("should return https URLs with paths as-is", () => {
+      const input = "https://api.example.com:443/ollama";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("https://api.example.com:443/ollama");
+    });
+  });
+
+  describe("hostname with port", () => {
+    it("should add http protocol to IPv4 host with port", () => {
+      const input = "192.168.1.100:8080";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://192.168.1.100:8080");
+    });
+
+    it("should add http protocol to localhost with custom port", () => {
+      const input = "localhost:8080";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://localhost:8080");
+    });
+
+    it("should add http protocol to domain with port", () => {
+      const input = "ollama.example.com:11434";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://ollama.example.com:11434");
+    });
+
+    it("should add http protocol to 0.0.0.0 with port", () => {
+      const input = "0.0.0.0:1234";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://0.0.0.0:1234");
+    });
+
+    it("should handle IPv6 with port", () => {
+      const input = "[::1]:8080";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://[::1]:8080");
+    });
+  });
+
+  describe("hostname only", () => {
+    it("should add http protocol and default port to IPv4 host", () => {
+      const input = "192.168.1.100";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://192.168.1.100:11434");
+    });
+
+    it("should add http protocol and default port to localhost", () => {
+      const input = "localhost";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://localhost:11434");
+    });
+
+    it("should add http protocol and default port to domain", () => {
+      const input = "ollama.example.com";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://ollama.example.com:11434");
+    });
+
+    it("should add http protocol and default port to 0.0.0.0", () => {
+      const input = "0.0.0.0";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://0.0.0.0:11434");
+    });
+
+    it("should handle IPv6 hostname", () => {
+      const input = "::1";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://[::1]:11434");
+    });
+
+    it("should handle full IPv6 hostname", () => {
+      const input = "2001:db8:85a3:0:0:8a2e:370:7334";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://[2001:db8:85a3:0:0:8a2e:370:7334]:11434");
+    });
+
+    it("should handle compressed IPv6 hostname", () => {
+      const input = "2001:db8::1";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://[2001:db8::1]:11434");
+    });
+  });
+
+  describe("edge cases", () => {
+    it("should handle hostname with unusual characters", () => {
+      const input = "my-ollama-server";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://my-ollama-server:11434");
+    });
+
+    it("should handle hostname with dots", () => {
+      const input = "my.ollama.server";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://my.ollama.server:11434");
+    });
+
+    it("should handle port 80", () => {
+      const input = "example.com:80";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://example.com:80");
+    });
+
+    it("should handle port 443", () => {
+      const input = "example.com:443";
+      const result = parseOllamaHost(input);
+      expect(result).toBe("http://example.com:443");
+    });
+  });
+});
diff --git a/src/ipc/handlers/local_model_ollama_handler.ts b/src/ipc/handlers/local_model_ollama_handler.ts
index c231ce6..e1ed804 100644
--- a/src/ipc/handlers/local_model_ollama_handler.ts
+++ b/src/ipc/handlers/local_model_ollama_handler.ts
@@ -4,7 +4,40 @@ import { LocalModelListResponse, LocalModel } from "../ipc_types";
 
 const logger = log.scope("ollama_handler");
 
-const OLLAMA_API_URL = process.env.OLLAMA_HOST || "http://localhost:11434";
+export function parseOllamaHost(host?: string): string {
+  if (!host) {
+    return "http://localhost:11434";
+  }
+
+  // If it already has a protocol, use as-is
+  if (host.startsWith("http://") || host.startsWith("https://")) {
+    return host;
+  }
+
+  // Check for bracketed IPv6 with port: [::1]:8080
+  if (host.startsWith("[") && host.includes("]:")) {
+    return `http://${host}`;
+  }
+
+  // Check for regular host:port (but not plain IPv6)
+  if (
+    host.includes(":") &&
+    !host.includes("::") &&
+    host.split(":").length === 2
+  ) {
+    return `http://${host}`;
+  }
+
+  // Check if it's a plain IPv6 address (contains :: or multiple colons)
+  if (host.includes("::") || host.split(":").length > 2) {
+    return `http://[${host}]:11434`;
+  }
+
+  // If it's just a hostname, add default port
+  return `http://${host}:11434`;
+}
+
+const OLLAMA_API_URL = parseOllamaHost(process.env.OLLAMA_HOST);
 
 interface OllamaModel {
   name: string;