Add OpenAI support, default to gpt-4o-mini

bun.lock

@@ -9,6 +9,7 @@
         "@elysiajs/cors": "^1.4.1",
         "@langchain/anthropic": "^1.3.12",
         "@langchain/core": "^1.1.17",
+        "@langchain/openai": "^1.2.3",
         "better-auth": "^1.4.17",
         "drizzle-orm": "^0.45.1",
         "elysia": "^1.4.22",
@@ -110,6 +111,8 @@
 
     "@langchain/core": ["@langchain/core@1.1.17", "", { "dependencies": { "@cfworker/json-schema": "^4.0.2", "ansi-styles": "^5.0.0", "camelcase": "6", "decamelize": "1.2.0", "js-tiktoken": "^1.0.12", "langsmith": ">=0.4.0 <1.0.0", "mustache": "^4.2.0", "p-queue": "^6.6.2", "uuid": "^10.0.0", "zod": "^3.25.76 || ^4" } }, "sha512-g7/kcKbKEwNZSyyT7aT0utxn7wTOtKErqz0cL6VjrV4v/aOb9g+dKcfj17YkSm42YQmJp/rB2IXGc17vQPEBqA=="],
 
+    "@langchain/openai": ["@langchain/openai@1.2.3", "", { "dependencies": { "js-tiktoken": "^1.0.12", "openai": "^6.16.0", "zod": "^3.25.76 || ^4" }, "peerDependencies": { "@langchain/core": "^1.0.0" } }, "sha512-+bKR4+Obz5a/NHEw0bAm3f/s4k0cXc/g46ZRRXqjcyDYP+9wFarItvGNn6DEEk5S7pGp1QqApAQNt9IZk1Ic1Q=="],
+
     "@noble/ciphers": ["@noble/ciphers@2.1.1", "", {}, "sha512-bysYuiVfhxNJuldNXlFEitTVdNnYUc+XNJZd7Qm2a5j1vZHgY+fazadNFWFaMK/2vye0JVlxV3gHmC0WDfAOQw=="],
 
     "@noble/hashes": ["@noble/hashes@2.0.1", "", {}, "sha512-XlOlEbQcE9fmuXxrVTXCTlG2nlRXa9Rj3rr5Ue/+tX+nmkgbX720YHh0VR3hBF9xDvwnb8D2shVGOwNx+ulArw=="],
@@ -212,6 +215,8 @@
 
     "non-error": ["non-error@0.1.0", "", {}, "sha512-TMB1uHiGsHRGv1uYclfhivcnf0/PdFp2pNqRxXjncaAsjYMoisaQJI+SSZCqRq+VliwRTC8tsMQfmrWjDMhkPQ=="],
 
+    "openai": ["openai@6.16.0", "", { "peerDependencies": { "ws": "^8.18.0", "zod": "^3.25 || ^4.0" }, "optionalPeers": ["ws", "zod"], "bin": { "openai": "bin/cli" } }, "sha512-fZ1uBqjFUjXzbGc35fFtYKEOxd20kd9fDpFeqWtsOZWiubY8CZ1NAlXHW3iathaFvqmNtCWMIsosCuyeI7Joxg=="],
+
     "openapi-types": ["openapi-types@12.1.3", "", {}, "sha512-N4YtSYJqghVu4iek2ZUvcN/0aqH1kRDuNqzcycDxhOUpg7GdvLa2F3DgS6yBNhInhv2r/6I0Flkn7CqL8+nIcw=="],
 
     "p-finally": ["p-finally@1.0.0", "", {}, "sha512-LICb2p9CB7FS+0eR1oqWnHhp0FljGLZCWBE9aix0Uye9W8LTQPwMTYVGWQWIw9RdQiDg4+epXQODwIYJtSJaow=="],

docker-compose.yml

@@ -28,6 +28,7 @@ services:
       ALLOWED_ORIGINS: ${ALLOWED_ORIGINS:-http://localhost:3000,http://localhost:8080}
       BETTER_AUTH_SECRET: ${BETTER_AUTH_SECRET}
       ANTHROPIC_API_KEY: ${ANTHROPIC_API_KEY}
+      OPENAI_API_KEY: ${OPENAI_API_KEY}
       RESEND_API_KEY: ${RESEND_API_KEY}
       DEFAULT_FROM_EMAIL: ${DEFAULT_FROM_EMAIL:-onboarding@resend.dev}
     depends_on:

package.json

@@ -28,6 +28,7 @@
     "@elysiajs/cors": "^1.4.1",
     "@langchain/anthropic": "^1.3.12",
     "@langchain/core": "^1.1.17",
+    "@langchain/openai": "^1.2.3",
     "better-auth": "^1.4.17",
     "drizzle-orm": "^0.45.1",
     "elysia": "^1.4.22",

src/services/ai.ts

@@ -1,11 +1,19 @@
 import { ChatAnthropic } from '@langchain/anthropic';
+import { ChatOpenAI } from '@langchain/openai';
 import { ChatPromptTemplate } from '@langchain/core/prompts';
 import { StringOutputParser } from '@langchain/core/output_parsers';
 
 export type AIProvider = 'anthropic' | 'openai';
 
 // Get model based on provider
-function getModel(provider: AIProvider = 'anthropic') {
+function getModel(provider: AIProvider = 'openai') {
+  if (provider === 'openai') {
+    return new ChatOpenAI({
+      modelName: 'gpt-4o-mini',
+      openAIApiKey: process.env.OPENAI_API_KEY,
+    });
+  }
+  
   if (provider === 'anthropic') {
     return new ChatAnthropic({
       modelName: 'claude-sonnet-4-20250514',
@@ -13,8 +21,7 @@ function getModel(provider: AIProvider = 'anthropic') {
     });
   }
   
-  // Add OpenAI support later
-  throw new Error(`Provider ${provider} not yet supported`);
+  throw new Error(`Provider ${provider} not supported`);
 }
 
 // Email generation prompt