fix: enable failover during stream iteration

src/Promptable.php

@@ -6,6 +6,7 @@
 use Illuminate\Broadcasting\Channel;
 use Illuminate\Container\Container;
 use Illuminate\Queue\SerializesModels;
+use Illuminate\Support\Str;
 use Laravel\Ai\Attributes\Model as ModelAttribute;
 use Laravel\Ai\Attributes\Provider as ProviderAttribute;
 use Laravel\Ai\Attributes\Timeout as TimeoutAttribute;
@@ -20,6 +21,7 @@
 use Laravel\Ai\Prompts\AgentPrompt;
 use Laravel\Ai\Providers\Provider;
 use Laravel\Ai\Responses\AgentResponse;
+use Laravel\Ai\Responses\Data\Meta;
 use Laravel\Ai\Responses\QueuedAgentResponse;
 use Laravel\Ai\Responses\StreamableAgentResponse;
 use Laravel\Ai\Streaming\Events\StreamEvent;
@@ -71,12 +73,57 @@ public function stream(
         ?string $model = null,
         ?int $timeout = null): StreamableAgentResponse
     {
-        return $this->withModelFailover(
-            fn (Provider $provider, string $model) => $provider->stream(
-                new AgentPrompt($this, $prompt, $attachments, $provider, $model, $this->getTimeout($timeout))
-            ),
-            $provider,
-            $model,
+        $providers = $this->getProvidersAndModels($provider, $model);
+        $resolvedTimeout = $this->getTimeout($timeout);
+
+        $resolvedProviders = [];
+
+        foreach ($providers as $p => $m) {
+            $resolved = Ai::textProviderFor($this, $p);
+            $resolvedProviders[] = [$resolved, $m ?? $this->getDefaultModelFor($resolved)];
+        }
+
+        if (empty($resolvedProviders)) {
+            throw new RuntimeException('No AI providers were configured.');
+        }
+
+        // Single provider: direct path (no failover needed)
+        if (count($resolvedProviders) === 1) {
+            [$singleProvider, $singleModel] = $resolvedProviders[0];
+
+            return $singleProvider->stream(
+                new AgentPrompt($this, $prompt, $attachments, $singleProvider, $singleModel, $resolvedTimeout)
+            );
+        }
+
+        // Multiple providers: failover-aware streaming
+        $agent = $this;
+        [$firstProvider, $firstModel] = $resolvedProviders[0];
+
+        return new StreamableAgentResponse(
+            (string) Str::uuid7(),
+            function () use ($resolvedProviders, $agent, $prompt, $attachments, $resolvedTimeout) {
+                $lastException = null;
+
+                foreach ($resolvedProviders as [$provider, $model]) {
+                    try {
+                        yield from $provider->stream(
+                            new AgentPrompt($agent, $prompt, $attachments, $provider, $model, $resolvedTimeout)
+                        );
+
+                        return;
+                    } catch (FailoverableException $e) {
+                        $lastException = $e;
+
+                        event(new AgentFailedOver($agent, $provider, $model, $e));
+
+                        continue;
+                    }
+                }
+
+                throw $lastException;
+            },
+            new Meta($firstProvider->name(), $firstModel),
         );
     }
 

tests/Feature/AgentStreamFailoverTest.php

@@ -0,0 +1,89 @@
+<?php
+
+namespace Tests\Feature;
+
+use Illuminate\Support\Facades\Event;
+use Illuminate\Support\Facades\Http;
+use Laravel\Ai\Events\AgentFailedOver;
+use Laravel\Ai\Exceptions\RateLimitedException;
+use Laravel\Ai\Streaming\Events\TextDelta;
+use Tests\Feature\Agents\AssistantAgent;
+use Tests\TestCase;
+
+class AgentStreamFailoverTest extends TestCase
+{
+    public function test_stream_fails_over_to_next_provider_when_primary_is_rate_limited(): void
+    {
+        Event::fake();
+
+        config([
+            'ai.providers.primary' => ['driver' => 'groq', 'key' => 'test-key'],
+            'ai.providers.backup' => ['driver' => 'groq', 'key' => 'test-key'],
+        ]);
+
+        Http::preventStrayRequests();
+
+        Http::fakeSequence()
+            ->push(status: 429)
+            ->push($this->fakeGroqStreamBody(), 200);
+
+        $response = (new AssistantAgent)->stream(
+            'Hello',
+            provider: ['primary', 'backup'],
+        );
+
+        $events = [];
+
+        foreach ($response as $event) {
+            $events[] = $event;
+        }
+
+        $this->assertTrue(
+            collect($events)->whereInstanceOf(TextDelta::class)->isNotEmpty()
+        );
+
+        Event::assertDispatched(AgentFailedOver::class);
+    }
+
+    public function test_stream_throws_last_exception_when_all_providers_fail(): void
+    {
+        config([
+            'ai.providers.primary' => ['driver' => 'groq', 'key' => 'test-key'],
+            'ai.providers.backup' => ['driver' => 'groq', 'key' => 'test-key'],
+        ]);
+
+        Http::preventStrayRequests();
+
+        Http::fakeSequence()
+            ->push(status: 429)
+            ->push(status: 429);
+
+        $this->expectException(RateLimitedException::class);
+
+        $response = (new AssistantAgent)->stream(
+            'Hello',
+            provider: ['primary', 'backup'],
+        );
+
+        foreach ($response as $event) {
+            //
+        }
+    }
+
+    private function fakeGroqStreamBody(): string
+    {
+        $chunks = [
+            '{"id":"chatcmpl-1","object":"chat.completion.chunk","created":1,"model":"test","choices":[{"index":0,"delta":{"role":"assistant","content":""},"finish_reason":null}]}',
+            '{"id":"chatcmpl-1","object":"chat.completion.chunk","created":1,"model":"test","choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}',
+            '{"id":"chatcmpl-1","object":"chat.completion.chunk","created":1,"model":"test","choices":[{"index":0,"delta":{},"finish_reason":"stop"}],"usage":{"prompt_tokens":5,"completion_tokens":1,"total_tokens":6}}',
+        ];
+
+        $body = '';
+
+        foreach ($chunks as $chunk) {
+            $body .= "data: {$chunk}\n\n";
+        }
+
+        return $body . "data: [DONE]\n\n";
+    }
+}