align google api key fallback, document model options

Author: nvms

docs/docs/advanced/image-generation.md

@@ -165,7 +165,7 @@ Environment variables are detected automatically.
 |----------|---------|
 | openai | `OPENAI_API_KEY` |
 | xai | `XAI_API_KEY` |
-| google | `GEMINI_API_KEY` |
+| google | `GEMINI_API_KEY` or `GOOGLE_AI_API_KEY` |
 
 Or use `setKeys()` - see [quick start](../quick-start.md#api-keys).
 

docs/docs/concepts/composition.md

@@ -46,6 +46,28 @@ Supported providers:
 - anthropic: `anthropic/<model-identifier>`
 - google: `google/<model-identifier>`
 
+### With Custom API Key
+
+```typescript
+const result = await model({
+  model: "openai/gpt-4o",
+  apiKey: "sk-different-key",
+})("explain quantum physics");
+```
+
+Useful for multi-tenant apps where each user has their own key.
+
+### With Custom Base URL
+
+```typescript
+const result = await model({
+  model: "openai/gpt-4o",
+  baseUrl: "https://my-proxy.example.com/v1",
+})("explain quantum physics");
+```
+
+Point to a proxy, gateway, or OpenAI-compatible API.
+
 ### With System Message
 
 ```typescript

docs/docs/quick-start.md

@@ -140,5 +140,3 @@ const workflow = compose(
 
 await workflow("what's the weather?");
 ```
-
-Next: [Threads](concepts/threads.md)

threads/src/image.ts

@@ -12,7 +12,8 @@ const getApiKey = (provider: string): string => {
     return getKey(provider);
   } catch {
     const envVar = providerKeyEnvVars[provider];
-    const key = envVar ? process.env[envVar] || "" : "";
+    const fallbackEnvVar = provider === "google" ? "GOOGLE_AI_API_KEY" : undefined;
+    const key = envVar ? process.env[envVar] || (fallbackEnvVar ? process.env[fallbackEnvVar] : "") || "" : "";
     if (!key) throw new Error(`No API key found for provider: ${provider}`);
     return key;
   }