diff --git a/docs/core-concepts/tools-function-calling.md b/docs/core-concepts/tools-function-calling.md
index 72d0a4154..8a6ef32f9 100644
--- a/docs/core-concepts/tools-function-calling.md
+++ b/docs/core-concepts/tools-function-calling.md
@@ -305,6 +305,56 @@ use Prism\Prism\Facades\Tool;
 $tool = Tool::make(CurrentWeatherTool::class);
 ```
 
+## Client-Executed Tools
+
+Sometimes you need tools that are executed by the client (e.g., frontend application) rather than on the server. Client-executed tools are defined without a handler function - simply omit the `using()` call:
+
+```php
+use Prism\Prism\Facades\Tool;
+
+$clientTool = Tool::as('browser_action')
+    ->for('Perform an action in the user\'s browser')
+    ->withStringParameter('action', 'The action to perform');
+    // Note: No using() call - this tool will be executed by the client
+```
+
+When the AI calls a client-executed tool, Prism will:
+1. Stop execution and return control to your application
+2. Set the response's `finishReason` to `FinishReason::ToolCalls`
+3. Include the tool calls in the response for your client to execute
+
+### Handling Client-Executed Tools
+
+```php
+use Prism\Prism\Facades\Prism;
+use Prism\Prism\Enums\FinishReason;
+
+$response = Prism::text()
+    ->using('anthropic', 'claude-3-5-sonnet-latest')
+    ->withTools([$clientTool])
+    ->withMaxSteps(3)
+    ->withPrompt('Click the submit button')
+    ->asText();
+
+```
+
+### Streaming with Client-Executed Tools
+
+When streaming, client-executed tools emit a `ToolCallEvent` but no `ToolResultEvent`:
+
+```php
+
+$response = Prism::text()
+    ->using('anthropic', 'claude-3-5-sonnet-latest')
+    ->withTools([$clientTool])
+    ->withMaxSteps(3)
+    ->withPrompt('Click the submit button')
+    ->asStream();
+```
+
+> [!NOTE]
+> Client-executed tools are useful for scenarios like browser automation, UI interactions, or any operation that must run on the user's device rather than the server.
+
 ## Tool Choice Options
 
 You can control how the AI uses tools with the `withToolChoice` method:
diff --git a/src/Concerns/CallsTools.php b/src/Concerns/CallsTools.php
index 1dec8b9c6..bd6320408 100644
--- a/src/Concerns/CallsTools.php
+++ b/src/Concerns/CallsTools.php
@@ -6,6 +6,7 @@
 
 use Illuminate\Support\ItemNotFoundException;
 use Illuminate\Support\MultipleItemsFoundException;
+use JsonException;
 use Prism\Prism\Exceptions\PrismException;
 use Prism\Prism\Tool;
 use Prism\Prism\ValueObjects\ToolCall;
@@ -18,6 +19,8 @@ trait CallsTools
      * @param  Tool[]  $tools
      * @param  ToolCall[]  $toolCalls
      * @return ToolResult[]
+     *
+     * @throws PrismException|JsonException
      */
     protected function callTools(array $tools, array $toolCalls): array
     {
@@ -47,12 +50,25 @@ function (ToolCall $toolCall) use ($tools): ToolResult {
                 }
 
             },
-            $toolCalls
+            array_filter($toolCalls, fn (ToolCall $toolCall): bool => ! $this->resolveTool($toolCall->name, $tools)->isClientExecuted())
         );
     }
 
     /**
      * @param  Tool[]  $tools
+     * @param  ToolCall[]  $toolCalls
+     *
+     * @throws PrismException
+     */
+    protected function hasDeferredTools(array $tools, array $toolCalls): bool
+    {
+        return array_any($toolCalls, fn (ToolCall $toolCall): bool => $this->resolveTool($toolCall->name, $tools)->isClientExecuted());
+    }
+
+    /**
+     * @param  Tool[]  $tools
+     *
+     * @throws PrismException
      */
     protected function resolveTool(string $name, array $tools): Tool
     {
diff --git a/src/Exceptions/PrismException.php b/src/Exceptions/PrismException.php
index 75ca9f3e0..636a6f4e1 100644
--- a/src/Exceptions/PrismException.php
+++ b/src/Exceptions/PrismException.php
@@ -76,4 +76,11 @@ public static function unsupportedProviderAction(string $method, string $provide
             $provider,
         ));
     }
+
+    public static function toolHandlerNotDefined(string $toolName): self
+    {
+        return new self(
+            sprintf('Tool (%s) has no handler defined', $toolName)
+        );
+    }
 }
diff --git a/src/Providers/Anthropic/Handlers/Stream.php b/src/Providers/Anthropic/Handlers/Stream.php
index 2b1e37240..cb7ed4332 100644
--- a/src/Providers/Anthropic/Handlers/Stream.php
+++ b/src/Providers/Anthropic/Handlers/Stream.php
@@ -443,9 +443,18 @@ protected function handleToolCalls(Request $request, int $depth): Generator
 
         // Execute tools and emit results
         $toolResults = [];
+        $hasDeferred = false;
         foreach ($toolCalls as $toolCall) {
             try {
                 $tool = $this->resolveTool($toolCall->name, $request->tools());
+
+                // Skip deferred tools - frontend will provide results
+                if ($tool->isClientExecuted()) {
+                    $hasDeferred = true;
+
+                    continue;
+                }
+
                 $result = call_user_func_array($tool->handle(...), $toolCall->arguments());
 
                 $toolResult = new ToolResult(
@@ -483,6 +492,17 @@ protected function handleToolCalls(Request $request, int $depth): Generator
             }
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($hasDeferred) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         // Add messages to request for next turn
         if ($toolResults !== []) {
             $request->addMessage(new AssistantMessage(
diff --git a/src/Providers/Anthropic/Handlers/Structured.php b/src/Providers/Anthropic/Handlers/Structured.php
index a720e9ed0..62149d533 100644
--- a/src/Providers/Anthropic/Handlers/Structured.php
+++ b/src/Providers/Anthropic/Handlers/Structured.php
@@ -172,7 +172,7 @@ protected function executeCustomToolsAndContinue(array $toolCalls, Response $tem
         $this->request->addMessage($message);
         $this->addStep($toolCalls, $tempResponse, $toolResults);
 
-        if ($this->canContinue()) {
+        if (! $this->hasDeferredTools($this->request->tools(), $toolCalls) && $this->canContinue()) {
             return $this->handle();
         }
 
diff --git a/src/Providers/Anthropic/Handlers/Text.php b/src/Providers/Anthropic/Handlers/Text.php
index b3c6c3dff..22a2c990d 100644
--- a/src/Providers/Anthropic/Handlers/Text.php
+++ b/src/Providers/Anthropic/Handlers/Text.php
@@ -113,7 +113,7 @@ protected function handleToolCalls(): Response
 
         $this->addStep($toolResults);
 
-        if ($this->responseBuilder->steps->count() < $this->request->maxSteps()) {
+        if (! $this->hasDeferredTools($this->request->tools(), $this->tempResponse->toolCalls) && $this->responseBuilder->steps->count() < $this->request->maxSteps()) {
             return $this->handle();
         }
 
diff --git a/src/Providers/DeepSeek/Handlers/Stream.php b/src/Providers/DeepSeek/Handlers/Stream.php
index e872f7395..f0f38826d 100644
--- a/src/Providers/DeepSeek/Handlers/Stream.php
+++ b/src/Providers/DeepSeek/Handlers/Stream.php
@@ -359,6 +359,17 @@ protected function handleToolCalls(Request $request, string $text, array $toolCa
             );
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($this->hasDeferredTools($request->tools(), $mappedToolCalls)) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         $request->addMessage(new AssistantMessage($text, $mappedToolCalls));
         $request->addMessage(new ToolResultMessage($toolResults));
 
diff --git a/src/Providers/DeepSeek/Handlers/Text.php b/src/Providers/DeepSeek/Handlers/Text.php
index 8645f13f2..2dae46cff 100644
--- a/src/Providers/DeepSeek/Handlers/Text.php
+++ b/src/Providers/DeepSeek/Handlers/Text.php
@@ -73,7 +73,10 @@ protected function handleToolCalls(array $data, Request $request): TextResponse
 
         $this->addStep($data, $request, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), ToolCallMap::map(data_get($data, 'choices.0.message.tool_calls', [])))
+            &&
+            $this->shouldContinue($request)
+        ) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/Gemini/Handlers/Stream.php b/src/Providers/Gemini/Handlers/Stream.php
index 864c3f89f..e7ca6463c 100644
--- a/src/Providers/Gemini/Handlers/Stream.php
+++ b/src/Providers/Gemini/Handlers/Stream.php
@@ -283,6 +283,7 @@ protected function handleToolCalls(
         array $data = []
     ): Generator {
         $mappedToolCalls = [];
+        $hasDeferred = false;
 
         // Convert tool calls to ToolCall objects
         foreach ($this->state->toolCalls() as $toolCallData) {
@@ -294,6 +295,14 @@ protected function handleToolCalls(
         foreach ($mappedToolCalls as $toolCall) {
             try {
                 $tool = $this->resolveTool($toolCall->name, $request->tools());
+
+                // Skip deferred tools - frontend will provide results
+                if ($tool->isClientExecuted()) {
+                    $hasDeferred = true;
+
+                    continue;
+                }
+
                 $result = call_user_func_array($tool->handle(...), $toolCall->arguments());
 
                 $toolResult = new ToolResult(
@@ -333,6 +342,17 @@ protected function handleToolCalls(
             }
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($hasDeferred) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         // Add messages for next turn and continue streaming
         if ($toolResults !== []) {
             $request->addMessage(new AssistantMessage($this->state->currentText(), $mappedToolCalls));
diff --git a/src/Providers/Gemini/Handlers/Structured.php b/src/Providers/Gemini/Handlers/Structured.php
index b0053a3d4..9238d9176 100644
--- a/src/Providers/Gemini/Handlers/Structured.php
+++ b/src/Providers/Gemini/Handlers/Structured.php
@@ -209,7 +209,7 @@ protected function handleToolCalls(array $data, Request $request): StructuredRes
 
         $this->addStep($data, $request, FinishReason::ToolCalls, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), ToolCallMap::map(data_get($data, 'candidates.0.content.parts', []))) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/Gemini/Handlers/Text.php b/src/Providers/Gemini/Handlers/Text.php
index 1384c6f4f..03eb28b23 100644
--- a/src/Providers/Gemini/Handlers/Text.php
+++ b/src/Providers/Gemini/Handlers/Text.php
@@ -156,7 +156,7 @@ protected function handleToolCalls(array $data, Request $request): TextResponse
 
         $this->addStep($data, $request, FinishReason::ToolCalls, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), ToolCallMap::map(data_get($data, 'candidates.0.content.parts', []))) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/Groq/Handlers/Stream.php b/src/Providers/Groq/Handlers/Stream.php
index 92f22e900..6180f1d03 100644
--- a/src/Providers/Groq/Handlers/Stream.php
+++ b/src/Providers/Groq/Handlers/Stream.php
@@ -257,6 +257,17 @@ protected function handleToolCalls(
             );
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($this->hasDeferredTools($request->tools(), $mappedToolCalls)) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         $request->addMessage(new AssistantMessage($text, $mappedToolCalls));
         $request->addMessage(new ToolResultMessage($toolResults));
 
diff --git a/src/Providers/Groq/Handlers/Text.php b/src/Providers/Groq/Handlers/Text.php
index 84e539bff..37c7ac299 100644
--- a/src/Providers/Groq/Handlers/Text.php
+++ b/src/Providers/Groq/Handlers/Text.php
@@ -95,7 +95,7 @@ protected function handleToolCalls(array $data, Request $request, ClientResponse
 
         $this->addStep($data, $request, $clientResponse, FinishReason::ToolCalls, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), $this->mapToolCalls(data_get($data, 'choices.0.message.tool_calls', []) ?? [])) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/Mistral/Handlers/Stream.php b/src/Providers/Mistral/Handlers/Stream.php
index 2b7c87095..437bcb2c5 100644
--- a/src/Providers/Mistral/Handlers/Stream.php
+++ b/src/Providers/Mistral/Handlers/Stream.php
@@ -251,6 +251,17 @@ protected function handleToolCalls(
             );
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($this->hasDeferredTools($request->tools(), $mappedToolCalls)) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         $request->addMessage(new AssistantMessage($text, $mappedToolCalls));
         $request->addMessage(new ToolResultMessage($toolResults));
 
diff --git a/src/Providers/Mistral/Handlers/Text.php b/src/Providers/Mistral/Handlers/Text.php
index a5582f0fd..c22953f23 100644
--- a/src/Providers/Mistral/Handlers/Text.php
+++ b/src/Providers/Mistral/Handlers/Text.php
@@ -81,7 +81,7 @@ protected function handleToolCalls(array $data, Request $request, ClientResponse
 
         $this->addStep($data, $request, $clientResponse, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), $this->mapToolCalls(data_get($data, 'choices.0.message.tool_calls', []))) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/Ollama/Handlers/Stream.php b/src/Providers/Ollama/Handlers/Stream.php
index f9b34eab6..ea634f3fc 100644
--- a/src/Providers/Ollama/Handlers/Stream.php
+++ b/src/Providers/Ollama/Handlers/Stream.php
@@ -273,6 +273,17 @@ protected function handleToolCalls(
             );
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($this->hasDeferredTools($request->tools(), $mappedToolCalls)) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         // Add messages for next turn
         $request->addMessage(new AssistantMessage($text, $mappedToolCalls));
         $request->addMessage(new ToolResultMessage($toolResults));
diff --git a/src/Providers/Ollama/Handlers/Text.php b/src/Providers/Ollama/Handlers/Text.php
index 04a63b3ee..b50a193dc 100644
--- a/src/Providers/Ollama/Handlers/Text.php
+++ b/src/Providers/Ollama/Handlers/Text.php
@@ -105,7 +105,7 @@ protected function handleToolCalls(array $data, Request $request): Response
 
         $this->addStep($data, $request, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), $this->mapToolCalls(data_get($data, 'message.tool_calls', []))) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
@@ -133,10 +133,18 @@ protected function shouldContinue(Request $request): bool
      */
     protected function addStep(array $data, Request $request, array $toolResults = []): void
     {
+        $toolCalls = $this->mapToolCalls(data_get($data, 'message.tool_calls', []) ?? []);
+
+        // Ollama sends done_reason: "stop" even when there are tool calls
+        // Override finish reason to ToolCalls when tool calls are present
+        $finishReason = $toolCalls === []
+            ? $this->mapFinishReason($data)
+            : FinishReason::ToolCalls;
+
         $this->responseBuilder->addStep(new Step(
             text: data_get($data, 'message.content') ?? '',
-            finishReason: $this->mapFinishReason($data),
-            toolCalls: $this->mapToolCalls(data_get($data, 'message.tool_calls', []) ?? []),
+            finishReason: $finishReason,
+            toolCalls: $toolCalls,
             toolResults: $toolResults,
             providerToolCalls: [],
             usage: new Usage(
diff --git a/src/Providers/OpenAI/Handlers/Stream.php b/src/Providers/OpenAI/Handlers/Stream.php
index dbb05c7b3..c363a9bde 100644
--- a/src/Providers/OpenAI/Handlers/Stream.php
+++ b/src/Providers/OpenAI/Handlers/Stream.php
@@ -352,6 +352,17 @@ protected function handleToolCalls(Request $request, int $depth): Generator
             );
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($this->hasDeferredTools($request->tools(), $mappedToolCalls)) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         $request->addMessage(new AssistantMessage($this->state->currentText(), $mappedToolCalls));
         $request->addMessage(new ToolResultMessage($toolResults));
 
diff --git a/src/Providers/OpenAI/Handlers/Structured.php b/src/Providers/OpenAI/Handlers/Structured.php
index b2c102d01..c9136aa1c 100644
--- a/src/Providers/OpenAI/Handlers/Structured.php
+++ b/src/Providers/OpenAI/Handlers/Structured.php
@@ -100,7 +100,7 @@ protected function handleToolCalls(array $data, Request $request, ClientResponse
 
         $this->addStep($data, $request, $clientResponse, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), ToolCallMap::map($this->extractFunctionCalls($data))) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/OpenAI/Handlers/Text.php b/src/Providers/OpenAI/Handlers/Text.php
index 6b2747442..980218179 100644
--- a/src/Providers/OpenAI/Handlers/Text.php
+++ b/src/Providers/OpenAI/Handlers/Text.php
@@ -100,7 +100,10 @@ protected function handleToolCalls(array $data, Request $request, ClientResponse
 
         $this->addStep($data, $request, $clientResponse, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), ToolCallMap::map(array_filter(data_get($data, 'output', []), fn (array $output): bool => $output['type'] === 'function_call')))
+            &&
+            $this->shouldContinue($request)
+        ) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/OpenRouter/Handlers/Stream.php b/src/Providers/OpenRouter/Handlers/Stream.php
index 35d630c89..7adce0d28 100644
--- a/src/Providers/OpenRouter/Handlers/Stream.php
+++ b/src/Providers/OpenRouter/Handlers/Stream.php
@@ -365,6 +365,17 @@ protected function handleToolCalls(
             );
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($this->hasDeferredTools($request->tools(), $mappedToolCalls)) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         $request->addMessage(new AssistantMessage($text, $mappedToolCalls));
         $request->addMessage(new ToolResultMessage($toolResults));
 
diff --git a/src/Providers/OpenRouter/Handlers/Text.php b/src/Providers/OpenRouter/Handlers/Text.php
index baf39954f..454b44b28 100644
--- a/src/Providers/OpenRouter/Handlers/Text.php
+++ b/src/Providers/OpenRouter/Handlers/Text.php
@@ -72,7 +72,7 @@ protected function handleToolCalls(array $data, Request $request): TextResponse
 
         $this->addStep($data, $request, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), ToolCallMap::map(data_get($data, 'choices.0.message.tool_calls', []))) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
diff --git a/src/Providers/XAI/Handlers/Stream.php b/src/Providers/XAI/Handlers/Stream.php
index f162e7055..7700c8373 100644
--- a/src/Providers/XAI/Handlers/Stream.php
+++ b/src/Providers/XAI/Handlers/Stream.php
@@ -346,6 +346,17 @@ protected function handleToolCalls(
             );
         }
 
+        // skip calling llm if there are pending deferred tools
+        if ($this->hasDeferredTools($request->tools(), $mappedToolCalls)) {
+            yield new StreamEndEvent(
+                id: EventID::generate(),
+                timestamp: time(),
+                finishReason: FinishReason::ToolCalls
+            );
+
+            return;
+        }
+
         $request->addMessage(new AssistantMessage($text, $mappedToolCalls));
         $request->addMessage(new ToolResultMessage($toolResults));
 
diff --git a/src/Providers/XAI/Handlers/Text.php b/src/Providers/XAI/Handlers/Text.php
index 5191a41d4..318da0b8b 100644
--- a/src/Providers/XAI/Handlers/Text.php
+++ b/src/Providers/XAI/Handlers/Text.php
@@ -83,7 +83,7 @@ protected function handleToolCalls(array $data, Request $request): TextResponse
 
         $this->addStep($data, $request, $toolResults);
 
-        if ($this->shouldContinue($request)) {
+        if (! $this->hasDeferredTools($request->tools(), $toolCalls) && $this->shouldContinue($request)) {
             return $this->handle($request);
         }
 
diff --git a/src/Tool.php b/src/Tool.php
index dd5a8c319..1b334d55d 100644
--- a/src/Tool.php
+++ b/src/Tool.php
@@ -37,7 +37,7 @@ class Tool
     /** @var array <int, string> */
     protected array $requiredParameters = [];
 
-    /** @var Closure():string|callable():string */
+    /** @var Closure():string|callable():string|null */
     protected $fn;
 
     /** @var null|false|Closure(Throwable,array<int|string,mixed>):string */
@@ -230,6 +230,11 @@ public function hasParameters(): bool
         return (bool) count($this->parameters);
     }
 
+    public function isClientExecuted(): bool
+    {
+        return $this->fn === null;
+    }
+
     /**
      * @return null|false|Closure(Throwable,array<int|string,mixed>):string
      */
@@ -245,6 +250,10 @@ public function failedHandler(): null|false|Closure
      */
     public function handle(...$args): string
     {
+        if ($this->fn === null) {
+            throw PrismException::toolHandlerNotDefined($this->name);
+        }
+
         try {
             $value = call_user_func($this->fn, ...$args);
 
diff --git a/tests/Fixtures/anthropic/stream-with-client-executed-tool-1.sse b/tests/Fixtures/anthropic/stream-with-client-executed-tool-1.sse
new file mode 100644
index 000000000..e6fcba676
--- /dev/null
+++ b/tests/Fixtures/anthropic/stream-with-client-executed-tool-1.sse
@@ -0,0 +1,31 @@
+event: message_start
+data: {"type":"message_start","message":{"id":"msg_client_executed_test","type":"message","role":"assistant","model":"claude-3-5-sonnet-20240620","content":[],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":100,"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"output_tokens":1}}}
+
+event: content_block_start
+data: {"type":"content_block_start","index":0,"content_block":{"type":"text","text":""}}
+
+event: content_block_delta
+data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"I'll use the client tool to help you."}}
+
+event: content_block_stop
+data: {"type":"content_block_stop","index":0}
+
+event: content_block_start
+data: {"type":"content_block_start","index":1,"content_block":{"type":"tool_use","id":"toolu_client_tool_stream","name":"client_tool","input":{}}}
+
+event: content_block_delta
+data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":""}}
+
+event: content_block_delta
+data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"{\"input\": \"test input\"}"}}
+
+event: content_block_stop
+data: {"type":"content_block_stop","index":1}
+
+event: message_delta
+data: {"type":"message_delta","delta":{"stop_reason":"tool_use","stop_sequence":null},"usage":{"output_tokens":50}}
+
+event: message_stop
+data: {"type":"message_stop"}
+
+
diff --git a/tests/Fixtures/anthropic/structured-with-client-executed-tool-1.json b/tests/Fixtures/anthropic/structured-with-client-executed-tool-1.json
new file mode 100644
index 000000000..980813079
--- /dev/null
+++ b/tests/Fixtures/anthropic/structured-with-client-executed-tool-1.json
@@ -0,0 +1,2 @@
+{"model":"claude-sonnet-4-20250514","id":"msg_client_executed_structured","type":"message","role":"assistant","content":[{"type":"text","text":"I'll use the client tool to help you with that request."},{"type":"tool_use","id":"toolu_client_structured","name":"client_tool","input":{"input":"test input"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":200,"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"output_tokens":50}}
+
diff --git a/tests/Fixtures/anthropic/text-with-client-executed-tool-1.json b/tests/Fixtures/anthropic/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..9d409fb32
--- /dev/null
+++ b/tests/Fixtures/anthropic/text-with-client-executed-tool-1.json
@@ -0,0 +1,2 @@
+{"id":"msg_01ClientExecutedTest","type":"message","role":"assistant","model":"claude-3-5-sonnet-20240620","content":[{"type":"text","text":"I'll use the client tool to help you with that."},{"type":"tool_use","id":"toolu_client_tool_123","name":"client_tool","input":{"input":"test input"}}],"stop_reason":"tool_use","stop_sequence":null,"usage":{"input_tokens":100,"output_tokens":50}}
+
diff --git a/tests/Fixtures/deepseek/stream-with-client-executed-tool-1.sse b/tests/Fixtures/deepseek/stream-with-client-executed-tool-1.sse
new file mode 100644
index 000000000..5dc224e2c
--- /dev/null
+++ b/tests/Fixtures/deepseek/stream-with-client-executed-tool-1.sse
@@ -0,0 +1,9 @@
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1737244481,"model":"deepseek-chat","choices":[{"index":0,"delta":{"role":"assistant","content":"","tool_calls":[{"index":0,"id":"call_client_tool_stream","type":"function","function":{"name":"client_tool","arguments":""}}]},"finish_reason":null}]}
+
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1737244481,"model":"deepseek-chat","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\"input\": \"test input\"}"}}]},"finish_reason":null}]}
+
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1737244481,"model":"deepseek-chat","choices":[{"index":0,"delta":{},"finish_reason":"tool_calls"}],"usage":{"prompt_tokens":100,"completion_tokens":50,"total_tokens":150}}
+
+data: [DONE]
+
+
diff --git a/tests/Fixtures/deepseek/text-with-client-executed-tool-1.json b/tests/Fixtures/deepseek/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..cc22dab36
--- /dev/null
+++ b/tests/Fixtures/deepseek/text-with-client-executed-tool-1.json
@@ -0,0 +1,2 @@
+{"id":"client-executed-test","object":"chat.completion","created":1737244481,"model":"deepseek-chat","choices":[{"index":0,"message":{"role":"assistant","content":"","tool_calls":[{"index":0,"id":"call_client_tool_123","type":"function","function":{"name":"client_tool","arguments":"{\"input\":\"test input\"}"}}]},"logprobs":null,"finish_reason":"tool_calls"}],"usage":{"prompt_tokens":100,"completion_tokens":50,"total_tokens":150},"system_fingerprint":"fp_test"}
+
diff --git a/tests/Fixtures/gemini/stream-with-client-executed-tool-1.json b/tests/Fixtures/gemini/stream-with-client-executed-tool-1.json
new file mode 100644
index 000000000..972a0996c
--- /dev/null
+++ b/tests/Fixtures/gemini/stream-with-client-executed-tool-1.json
@@ -0,0 +1,3 @@
+data: {"candidates": [{"content": {"parts": [{"functionCall": {"name": "client_tool","args": {"input": "test input"}}}],"role": "model"},"finishReason": "STOP","index": 0}],"usageMetadata": {"promptTokenCount": 100,"candidatesTokenCount": 50,"totalTokenCount": 150,"promptTokensDetails": [{"modality": "TEXT","tokenCount": 100}]},"modelVersion": "gemini-1.5-flash"}
+
+
diff --git a/tests/Fixtures/gemini/structured-with-client-executed-tool-1.json b/tests/Fixtures/gemini/structured-with-client-executed-tool-1.json
new file mode 100644
index 000000000..c5a633d1c
--- /dev/null
+++ b/tests/Fixtures/gemini/structured-with-client-executed-tool-1.json
@@ -0,0 +1,40 @@
+{
+  "candidates": [
+    {
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "name": "client_tool",
+              "args": {
+                "input": "test input"
+              }
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "avgLogprobs": -0.00003298009687569
+    }
+  ],
+  "usageMetadata": {
+    "promptTokenCount": 200,
+    "candidatesTokenCount": 50,
+    "totalTokenCount": 250,
+    "promptTokensDetails": [
+      {
+        "modality": "TEXT",
+        "tokenCount": 200
+      }
+    ],
+    "candidatesTokensDetails": [
+      {
+        "modality": "TEXT",
+        "tokenCount": 50
+      }
+    ]
+  },
+  "modelVersion": "gemini-2.0-flash"
+}
+
diff --git a/tests/Fixtures/gemini/text-with-client-executed-tool-1.json b/tests/Fixtures/gemini/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..5fb57e5b9
--- /dev/null
+++ b/tests/Fixtures/gemini/text-with-client-executed-tool-1.json
@@ -0,0 +1,40 @@
+{
+  "candidates": [
+    {
+      "content": {
+        "parts": [
+          {
+            "functionCall": {
+              "name": "client_tool",
+              "args": {
+                "input": "test input"
+              }
+            }
+          }
+        ],
+        "role": "model"
+      },
+      "finishReason": "STOP",
+      "avgLogprobs": -0.00003298009687569
+    }
+  ],
+  "usageMetadata": {
+    "promptTokenCount": 100,
+    "candidatesTokenCount": 50,
+    "totalTokenCount": 150,
+    "promptTokensDetails": [
+      {
+        "modality": "TEXT",
+        "tokenCount": 100
+      }
+    ],
+    "candidatesTokensDetails": [
+      {
+        "modality": "TEXT",
+        "tokenCount": 50
+      }
+    ]
+  },
+  "modelVersion": "gemini-1.5-flash"
+}
+
diff --git a/tests/Fixtures/groq/stream-with-client-executed-tool-1.sse b/tests/Fixtures/groq/stream-with-client-executed-tool-1.sse
new file mode 100644
index 000000000..c750092fc
--- /dev/null
+++ b/tests/Fixtures/groq/stream-with-client-executed-tool-1.sse
@@ -0,0 +1,9 @@
+data: {"id":"chatcmpl-client-executed-stream","object":"chat.completion.chunk","created":1740311145,"model":"llama-3.3-70b-versatile","choices":[{"index":0,"delta":{"role":"assistant","tool_calls":[{"index":0,"id":"call_client_tool_stream","type":"function","function":{"name":"client_tool","arguments":""}}]},"logprobs":null,"finish_reason":null}],"x_groq":{"id":"req_test"}}
+
+data: {"id":"chatcmpl-client-executed-stream","object":"chat.completion.chunk","created":1740311145,"model":"llama-3.3-70b-versatile","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\"input\": \"test input\"}"}}]},"logprobs":null,"finish_reason":null}],"x_groq":{"id":"req_test"}}
+
+data: {"id":"chatcmpl-client-executed-stream","object":"chat.completion.chunk","created":1740311145,"model":"llama-3.3-70b-versatile","choices":[{"index":0,"delta":{},"logprobs":null,"finish_reason":"tool_calls"}],"usage":{"queue_time":0.1,"prompt_tokens":100,"prompt_time":0.01,"completion_tokens":50,"completion_time":0.1,"total_tokens":150,"total_time":0.2},"x_groq":{"id":"req_test"}}
+
+data: [DONE]
+
+
diff --git a/tests/Fixtures/groq/text-with-client-executed-tool-1.json b/tests/Fixtures/groq/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..eecec7bb8
--- /dev/null
+++ b/tests/Fixtures/groq/text-with-client-executed-tool-1.json
@@ -0,0 +1,2 @@
+{"id":"chatcmpl-client-executed","object":"chat.completion","created":1740311145,"model":"llama-3.3-70b-versatile","choices":[{"index":0,"message":{"role":"assistant","tool_calls":[{"id":"call_client_tool","type":"function","function":{"name":"client_tool","arguments":"{\"input\": \"test input\"}"}}]},"logprobs":null,"finish_reason":"tool_calls"}],"usage":{"queue_time":0.1,"prompt_tokens":100,"prompt_time":0.01,"completion_tokens":50,"completion_time":0.1,"total_tokens":150,"total_time":0.2},"system_fingerprint":"fp_test"}
+
diff --git a/tests/Fixtures/mistral/stream-with-client-executed-tool-1.sse b/tests/Fixtures/mistral/stream-with-client-executed-tool-1.sse
new file mode 100644
index 000000000..756442567
--- /dev/null
+++ b/tests/Fixtures/mistral/stream-with-client-executed-tool-1.sse
@@ -0,0 +1,6 @@
+data: {"id":"client-executed-test","object":"chat.completion.chunk","created":1759185828,"model":"mistral-large-latest","choices":[{"index":0,"delta":{"role":"assistant","content":""},"finish_reason":null}]}
+
+data: {"id":"client-executed-test","object":"chat.completion.chunk","created":1759185828,"model":"mistral-large-latest","choices":[{"index":0,"delta":{"tool_calls":[{"id":"client_tool_stream","function":{"name":"client_tool","arguments":"{\"input\": \"test input\"}"},"index":0}]},"finish_reason":"tool_calls"}],"usage":{"prompt_tokens":100,"total_tokens":150,"completion_tokens":50}}
+
+data: [DONE]
+
diff --git a/tests/Fixtures/mistral/text-with-client-executed-tool-1.json b/tests/Fixtures/mistral/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..21a812489
--- /dev/null
+++ b/tests/Fixtures/mistral/text-with-client-executed-tool-1.json
@@ -0,0 +1,32 @@
+{
+  "id": "client_executed_test",
+  "object": "chat.completion",
+  "created": 1728462827,
+  "model": "mistral-large-latest",
+  "choices": [
+    {
+      "index": 0,
+      "message": {
+        "role": "assistant",
+        "content": "",
+        "tool_calls": [
+          {
+            "id": "client_tool_123",
+            "type": "function",
+            "function": {
+              "name": "client_tool",
+              "arguments": "{\"input\": \"test input\"}"
+            }
+          }
+        ]
+      },
+      "finish_reason": "tool_calls"
+    }
+  ],
+  "usage": {
+    "prompt_tokens": 100,
+    "total_tokens": 150,
+    "completion_tokens": 50
+  }
+}
+
diff --git a/tests/Fixtures/ollama/stream-with-client-executed-tool-1.sse b/tests/Fixtures/ollama/stream-with-client-executed-tool-1.sse
new file mode 100644
index 000000000..044f3d26e
--- /dev/null
+++ b/tests/Fixtures/ollama/stream-with-client-executed-tool-1.sse
@@ -0,0 +1,3 @@
+{"model":"qwen2.5:14b","created_at":"2025-06-09T18:55:26.684517Z","message":{"role":"assistant","content":"","tool_calls":[{"function":{"name":"client_tool","arguments":{"input":"test input"}}}]},"done_reason":"stop","done":true,"total_duration":8210142000,"load_duration":22224542,"prompt_eval_count":100,"prompt_eval_duration":269880958,"eval_count":50,"eval_duration":7916594250}
+
+
diff --git a/tests/Fixtures/ollama/text-with-client-executed-tool-1.json b/tests/Fixtures/ollama/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..d5d619328
--- /dev/null
+++ b/tests/Fixtures/ollama/text-with-client-executed-tool-1.json
@@ -0,0 +1,2 @@
+{"model":"qwen2.5:14b","created_at":"2025-06-09T18:55:26.684517Z","message":{"role":"assistant","content":"","tool_calls":[{"function":{"name":"client_tool","arguments":{"input":"test input"}}}]},"done_reason":"stop","done":true,"total_duration":8210142000,"load_duration":22224542,"prompt_eval_count":100,"prompt_eval_duration":269880958,"eval_count":50,"eval_duration":7916594250}
+
diff --git a/tests/Fixtures/openai/stream-with-client-executed-tool-1.json b/tests/Fixtures/openai/stream-with-client-executed-tool-1.json
new file mode 100644
index 000000000..272daa16c
--- /dev/null
+++ b/tests/Fixtures/openai/stream-with-client-executed-tool-1.json
@@ -0,0 +1,22 @@
+event: response.created
+data: {"type":"response.created","sequence_number":0,"response":{"id":"resp_client_executed_stream","object":"response","created_at":1750705330,"status":"in_progress","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":2048,"model":"gpt-4o-2024-08-06","output":[],"parallel_tool_calls":true,"previous_response_id":null,"reasoning":{"effort":null,"summary":null},"service_tier":"auto","store":true,"temperature":1.0,"text":{"format":{"type":"text"}},"tool_choice":"auto","tools":[{"type":"function","description":"A tool that executes on the client","name":"client_tool","parameters":{"type":"object","properties":{"input":{"description":"Input parameter","type":"string"}},"required":["input"]},"strict":true}],"top_p":1.0,"truncation":"disabled","usage":null,"user":null,"metadata":{}}}
+
+event: response.in_progress
+data: {"type":"response.in_progress","sequence_number":1,"response":{"id":"resp_client_executed_stream","object":"response","created_at":1750705330,"status":"in_progress","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":2048,"model":"gpt-4o-2024-08-06","output":[],"parallel_tool_calls":true,"previous_response_id":null,"reasoning":{"effort":null,"summary":null},"service_tier":"auto","store":true,"temperature":1.0,"text":{"format":{"type":"text"}},"tool_choice":"auto","tools":[{"type":"function","description":"A tool that executes on the client","name":"client_tool","parameters":{"type":"object","properties":{"input":{"description":"Input parameter","type":"string"}},"required":["input"]},"strict":true}],"top_p":1.0,"truncation":"disabled","usage":null,"user":null,"metadata":{}}}
+
+event: response.output_item.added
+data: {"type":"response.output_item.added","sequence_number":2,"output_index":0,"item":{"id":"fc_client_tool_stream","type":"function_call","status":"in_progress","arguments":"","call_id":"call_client_tool_stream","name":"client_tool"}}
+
+event: response.function_call_arguments.delta
+data: {"type":"response.function_call_arguments.delta","sequence_number":3,"item_id":"fc_client_tool_stream","output_index":0,"delta":"{\"input\":\"test input\"}"}
+
+event: response.function_call_arguments.done
+data: {"type":"response.function_call_arguments.done","sequence_number":4,"item_id":"fc_client_tool_stream","output_index":0,"arguments":"{\"input\":\"test input\"}"}
+
+event: response.output_item.done
+data: {"type":"response.output_item.done","sequence_number":5,"output_index":0,"item":{"id":"fc_client_tool_stream","type":"function_call","status":"completed","arguments":"{\"input\":\"test input\"}","call_id":"call_client_tool_stream","name":"client_tool"}}
+
+event: response.completed
+data: {"type":"response.completed","sequence_number":6,"response":{"id":"resp_client_executed_stream","object":"response","created_at":1750705330,"status":"completed","background":false,"error":null,"incomplete_details":null,"instructions":null,"max_output_tokens":2048,"model":"gpt-4o-2024-08-06","output":[{"id":"fc_client_tool_stream","type":"function_call","status":"completed","arguments":"{\"input\":\"test input\"}","call_id":"call_client_tool_stream","name":"client_tool"}],"parallel_tool_calls":true,"previous_response_id":null,"reasoning":{"effort":null,"summary":null},"service_tier":"default","store":true,"temperature":1.0,"text":{"format":{"type":"text"}},"tool_choice":"auto","tools":[{"type":"function","description":"A tool that executes on the client","name":"client_tool","parameters":{"type":"object","properties":{"input":{"description":"Input parameter","type":"string"}},"required":["input"]},"strict":true}],"top_p":1.0,"truncation":"disabled","usage":{"input_tokens":100,"input_tokens_details":{"cached_tokens":0},"output_tokens":50,"output_tokens_details":{"reasoning_tokens":0},"total_tokens":150},"user":null,"metadata":{}}}
+
+
diff --git a/tests/Fixtures/openai/structured-with-client-executed-tool-1.json b/tests/Fixtures/openai/structured-with-client-executed-tool-1.json
new file mode 100644
index 000000000..8aff9433b
--- /dev/null
+++ b/tests/Fixtures/openai/structured-with-client-executed-tool-1.json
@@ -0,0 +1,31 @@
+{
+  "id": "resp_structured_client_executed",
+  "object": "response",
+  "created_at": 1741989983,
+  "status": "completed",
+  "model": "gpt-4o-2024-08-06",
+  "output": [
+    {
+      "id": "fc_client_tool_structured",
+      "type": "function_call",
+      "status": "completed",
+      "arguments": "{\"input\": \"test input\"}",
+      "call_id": "call_client_tool_structured",
+      "name": "client_tool"
+    }
+  ],
+  "usage": {
+    "input_tokens": 200,
+    "input_tokens_details": {
+      "cached_tokens": 0
+    },
+    "output_tokens": 50,
+    "output_tokens_details": {
+      "reasoning_tokens": 0
+    },
+    "total_tokens": 250
+  },
+  "service_tier": "default",
+  "system_fingerprint": "fp_test"
+}
+
diff --git a/tests/Fixtures/openai/text-with-client-executed-tool-1.json b/tests/Fixtures/openai/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..a62212d13
--- /dev/null
+++ b/tests/Fixtures/openai/text-with-client-executed-tool-1.json
@@ -0,0 +1,31 @@
+{
+  "id": "resp_client_executed_test",
+  "object": "response",
+  "created_at": 1741989983,
+  "status": "completed",
+  "model": "gpt-4o-2024-08-06",
+  "output": [
+    {
+      "id": "fc_client_tool_123",
+      "type": "function_call",
+      "status": "completed",
+      "arguments": "{\"input\": \"test input\"}",
+      "call_id": "call_client_tool_123",
+      "name": "client_tool"
+    }
+  ],
+  "usage": {
+    "input_tokens": 100,
+    "input_tokens_details": {
+      "cached_tokens": 0
+    },
+    "output_tokens": 50,
+    "output_tokens_details": {
+      "reasoning_tokens": 0
+    },
+    "total_tokens": 150
+  },
+  "service_tier": "default",
+  "system_fingerprint": "fp_test"
+}
+
diff --git a/tests/Fixtures/openrouter/stream-with-client-executed-tool-1.sse b/tests/Fixtures/openrouter/stream-with-client-executed-tool-1.sse
new file mode 100644
index 000000000..e0a4d5e6c
--- /dev/null
+++ b/tests/Fixtures/openrouter/stream-with-client-executed-tool-1.sse
@@ -0,0 +1,9 @@
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1737243487,"model":"openai/gpt-4-turbo","choices":[{"index":0,"delta":{"role":"assistant","tool_calls":[{"index":0,"id":"call_client_tool_stream","type":"function","function":{"name":"client_tool","arguments":""}}]},"logprobs":null,"finish_reason":null}]}
+
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1737243487,"model":"openai/gpt-4-turbo","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\"input\": \"test input\"}"}}]},"logprobs":null,"finish_reason":null}]}
+
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1737243487,"model":"openai/gpt-4-turbo","choices":[{"index":0,"delta":{},"logprobs":null,"finish_reason":"tool_calls"}],"usage":{"prompt_tokens":100,"completion_tokens":50,"total_tokens":150}}
+
+data: [DONE]
+
+
diff --git a/tests/Fixtures/openrouter/text-with-client-executed-tool-1.json b/tests/Fixtures/openrouter/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..5afde1944
--- /dev/null
+++ b/tests/Fixtures/openrouter/text-with-client-executed-tool-1.json
@@ -0,0 +1,2 @@
+{"id":"gen-client-executed","object":"chat.completion","created":1737243487,"model":"openai/gpt-4-turbo","choices":[{"index":0,"message":{"role":"assistant","content":"","tool_calls":[{"id":"call_client_tool","type":"function","function":{"name":"client_tool","arguments":"{\"input\":\"test input\"}"}}]},"logprobs":null,"finish_reason":"tool_calls"}],"usage":{"prompt_tokens":100,"completion_tokens":50,"total_tokens":150}}
+
diff --git a/tests/Fixtures/xai/stream-with-client-executed-tool-1.json b/tests/Fixtures/xai/stream-with-client-executed-tool-1.json
new file mode 100644
index 000000000..63313a45e
--- /dev/null
+++ b/tests/Fixtures/xai/stream-with-client-executed-tool-1.json
@@ -0,0 +1,9 @@
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1731129810,"model":"grok-4","choices":[{"index":0,"delta":{"role":"assistant","tool_calls":[{"index":0,"id":"0","type":"function","function":{"name":"client_tool","arguments":""}}]},"logprobs":null,"finish_reason":null}]}
+
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1731129810,"model":"grok-4","choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\"input\":\"test input\"}"}}]},"logprobs":null,"finish_reason":null}]}
+
+data: {"id":"chatcmpl-client-executed","object":"chat.completion.chunk","created":1731129810,"model":"grok-4","choices":[{"index":0,"delta":{},"logprobs":null,"finish_reason":"tool_calls"}],"usage":{"prompt_tokens":100,"completion_tokens":50,"total_tokens":150}}
+
+data: [DONE]
+
+
diff --git a/tests/Fixtures/xai/text-with-client-executed-tool-1.json b/tests/Fixtures/xai/text-with-client-executed-tool-1.json
new file mode 100644
index 000000000..064707bc0
--- /dev/null
+++ b/tests/Fixtures/xai/text-with-client-executed-tool-1.json
@@ -0,0 +1,34 @@
+{
+  "id": "client-executed-test",
+  "object": "chat.completion",
+  "created": 1731129810,
+  "model": "grok-beta",
+  "choices": [
+    {
+      "index": 0,
+      "message": {
+        "role": "assistant",
+        "content": "",
+        "tool_calls": [
+          {
+            "id": "0",
+            "function": {
+              "name": "client_tool",
+              "arguments": "{\"input\":\"test input\"}"
+            },
+            "type": "function"
+          }
+        ],
+        "refusal": null
+      },
+      "finish_reason": "tool_calls"
+    }
+  ],
+  "usage": {
+    "prompt_tokens": 100,
+    "completion_tokens": 50,
+    "total_tokens": 150
+  },
+  "system_fingerprint": "fp_test"
+}
+
diff --git a/tests/Providers/Anthropic/AnthropicTextTest.php b/tests/Providers/Anthropic/AnthropicTextTest.php
index c04791bfe..e335bb4fa 100644
--- a/tests/Providers/Anthropic/AnthropicTextTest.php
+++ b/tests/Providers/Anthropic/AnthropicTextTest.php
@@ -523,6 +523,28 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/messages', 'anthropic/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('anthropic', 'claude-3-5-sonnet-20240620')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asText();
+
+        expect($response->finishReason)->toBe(\Prism\Prism\Enums\FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+});
+
 describe('exceptions', function (): void {
     it('throws a RateLimitException if the Anthropic responds with a 429', function (): void {
         Http::fake([
diff --git a/tests/Providers/Anthropic/StreamTest.php b/tests/Providers/Anthropic/StreamTest.php
index 625a3d99d..65977bab9 100644
--- a/tests/Providers/Anthropic/StreamTest.php
+++ b/tests/Providers/Anthropic/StreamTest.php
@@ -598,6 +598,40 @@
     })->throws(PrismRequestTooLargeException::class);
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeStreamResponses('v1/messages', 'anthropic/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('anthropic', 'claude-3-5-sonnet-20240620')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(\Prism\Prism\Enums\FinishReason::ToolCalls);
+    });
+});
+
 describe('basic stream events', function (): void {
     it('can generate text with a basic stream', function (): void {
         FixtureResponse::fakeStreamResponses('v1/messages', 'anthropic/stream-basic-text');
diff --git a/tests/Providers/Anthropic/StructuredWithToolsTest.php b/tests/Providers/Anthropic/StructuredWithToolsTest.php
index 9e904d1ce..8cd38e0a4 100644
--- a/tests/Providers/Anthropic/StructuredWithToolsTest.php
+++ b/tests/Providers/Anthropic/StructuredWithToolsTest.php
@@ -200,6 +200,36 @@
         expect($response->toolResults)->toBeArray();
     });
 
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('*', 'anthropic/structured-with-client-executed-tool');
+
+        $schema = new ObjectSchema(
+            'output',
+            'the output object',
+            [new StringSchema('result', 'The result', true)],
+            ['result']
+        );
+
+        $tool = (new Tool)
+            ->as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::structured()
+            ->using(Provider::Anthropic, 'claude-sonnet-4-0')
+            ->withSchema($schema)
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withProviderOptions(['use_tool_calling' => true])
+            ->withPrompt('Use the client tool')
+            ->asStructured();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+
     it('includes strict field in tool definition when specified', function (): void {
         Prism::fake();
 
diff --git a/tests/Providers/DeepSeek/StreamTest.php b/tests/Providers/DeepSeek/StreamTest.php
index d38c47ae2..a3cdd2323 100644
--- a/tests/Providers/DeepSeek/StreamTest.php
+++ b/tests/Providers/DeepSeek/StreamTest.php
@@ -126,6 +126,40 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeStreamResponses('chat/completions', 'deepseek/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::DeepSeek, 'deepseek-chat')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(FinishReason::ToolCalls);
+    });
+});
+
 it('handles max_tokens parameter correctly', function (): void {
     FixtureResponse::fakeStreamResponses('chat/completions', 'deepseek/stream-max-tokens');
 
diff --git a/tests/Providers/DeepSeek/TextTest.php b/tests/Providers/DeepSeek/TextTest.php
index e6fd3ccb6..2da324961 100644
--- a/tests/Providers/DeepSeek/TextTest.php
+++ b/tests/Providers/DeepSeek/TextTest.php
@@ -76,6 +76,28 @@
     expect($response->finishReason)->toBe(FinishReason::Stop);
 });
 
+describe('client-executed tools', function (): void {
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/chat/completions', 'deepseek/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::DeepSeek, 'deepseek-chat')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->generate();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+});
+
 it('can generate text using multiple tools and multiple steps', function (): void {
     FixtureResponse::fakeResponseSequence('v1/chat/completions', 'deepseek/generate-text-with-multiple-tools');
 
diff --git a/tests/Providers/Gemini/GeminiStreamTest.php b/tests/Providers/Gemini/GeminiStreamTest.php
index 5dca1bc9a..ba86212cc 100644
--- a/tests/Providers/Gemini/GeminiStreamTest.php
+++ b/tests/Providers/Gemini/GeminiStreamTest.php
@@ -229,6 +229,40 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('*', 'gemini/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::Gemini, 'gemini-1.5-flash')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(FinishReason::ToolCalls);
+    });
+});
+
 it('yields ToolCall events before ToolResult events', function (): void {
     FixtureResponse::fakeResponseSequence('*', 'gemini/stream-with-tools');
 
diff --git a/tests/Providers/Gemini/GeminiTextTest.php b/tests/Providers/Gemini/GeminiTextTest.php
index c07bbed08..a7dc2c638 100644
--- a/tests/Providers/Gemini/GeminiTextTest.php
+++ b/tests/Providers/Gemini/GeminiTextTest.php
@@ -154,6 +154,29 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('*', 'gemini/text-with-client-executed-tool');
+
+        $tool = (new Tool)
+            ->as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::Gemini, 'gemini-1.5-flash')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asText();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+});
+
 describe('Image support with Gemini', function (): void {
     it('can send images from path', function (): void {
         FixtureResponse::fakeResponseSequence('*', 'gemini/image-detection');
diff --git a/tests/Providers/Gemini/StructuredWithToolsTest.php b/tests/Providers/Gemini/StructuredWithToolsTest.php
index 36d94de36..bd167bd27 100644
--- a/tests/Providers/Gemini/StructuredWithToolsTest.php
+++ b/tests/Providers/Gemini/StructuredWithToolsTest.php
@@ -120,6 +120,35 @@
         expect($finalStep->structured)->toBeArray();
     });
 
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('*', 'gemini/structured-with-client-executed-tool');
+
+        $schema = new ObjectSchema(
+            'output',
+            'the output object',
+            [new StringSchema('result', 'The result', true)],
+            ['result']
+        );
+
+        $tool = (new Tool)
+            ->as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::structured()
+            ->using(Provider::Gemini, 'gemini-2.0-flash')
+            ->withSchema($schema)
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStructured();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+
     it('returns structured output immediately when no tool calls needed', function (): void {
         FixtureResponse::fakeResponseSequence('*', 'gemini/structured-without-tool-calls');
 
diff --git a/tests/Providers/Groq/GroqTextTest.php b/tests/Providers/Groq/GroqTextTest.php
index 98ba516f4..3ecba36a7 100644
--- a/tests/Providers/Groq/GroqTextTest.php
+++ b/tests/Providers/Groq/GroqTextTest.php
@@ -107,6 +107,26 @@
         );
     });
 
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('chat/completions', 'groq/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('groq', 'llama-3.3-70b-versatile')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->generate();
+
+        expect($response->finishReason)->toBe(\Prism\Prism\Enums\FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+
     it('handles specific tool choice', function (): void {
         FixtureResponse::fakeResponseSequence('v1/chat/completions', 'groq/generate-text-with-required-tool-call');
 
diff --git a/tests/Providers/Groq/StreamTest.php b/tests/Providers/Groq/StreamTest.php
index b89b61f6c..7482d39d8 100644
--- a/tests/Providers/Groq/StreamTest.php
+++ b/tests/Providers/Groq/StreamTest.php
@@ -113,6 +113,40 @@
     expect($toolResultEvents)->not->toBeEmpty();
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeStreamResponses('openai/v1/chat/completions', 'groq/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::Groq, 'llama-3.1-70b-versatile')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(FinishReason::ToolCalls);
+    });
+});
+
 it('handles maximum tool call depth exceeded', function (): void {
     FixtureResponse::fakeStreamResponses('openai/v1/chat/completions', 'groq/stream-with-tools');
 
diff --git a/tests/Providers/Mistral/MistralTextTest.php b/tests/Providers/Mistral/MistralTextTest.php
index 03aa42fd0..09d6df205 100644
--- a/tests/Providers/Mistral/MistralTextTest.php
+++ b/tests/Providers/Mistral/MistralTextTest.php
@@ -106,6 +106,26 @@
         );
     });
 
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/chat/completions', 'mistral/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('mistral', 'mistral-large-latest')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->generate();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+
     it('handles specific tool choice', function (): void {
         FixtureResponse::fakeResponseSequence('v1/chat/completions', 'mistral/generate-text-with-required-tool-call');
 
diff --git a/tests/Providers/Mistral/StreamTest.php b/tests/Providers/Mistral/StreamTest.php
index 091e48677..aec373ccf 100644
--- a/tests/Providers/Mistral/StreamTest.php
+++ b/tests/Providers/Mistral/StreamTest.php
@@ -112,6 +112,40 @@
     expect($toolResultEvents)->not->toBeEmpty();
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeStreamResponses('v1/chat/completions', 'mistral/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::Mistral, 'mistral-large-latest')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(FinishReason::ToolCalls);
+    });
+});
+
 it('handles maximum tool call depth exceeded', function (): void {
     FixtureResponse::fakeStreamResponses('v1/chat/completions', 'mistral/stream-with-tools-1');
 
diff --git a/tests/Providers/Ollama/StreamTest.php b/tests/Providers/Ollama/StreamTest.php
index 0159d9832..8677ddd1a 100644
--- a/tests/Providers/Ollama/StreamTest.php
+++ b/tests/Providers/Ollama/StreamTest.php
@@ -117,6 +117,40 @@
     expect($finishReasonFound)->toBeTrue();
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeStreamResponses('api/chat', 'ollama/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('ollama', 'qwen2.5:14b')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(FinishReason::ToolCalls);
+    });
+});
+
 it('throws a PrismRateLimitedException with a 429 response code', function (): void {
     Http::fake([
         '*' => Http::response(
diff --git a/tests/Providers/Ollama/TextTest.php b/tests/Providers/Ollama/TextTest.php
index 9b355d7c5..ed667555c 100644
--- a/tests/Providers/Ollama/TextTest.php
+++ b/tests/Providers/Ollama/TextTest.php
@@ -104,6 +104,28 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('api/chat', 'ollama/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('ollama', 'qwen2.5:14b')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asText();
+
+        expect($response->finishReason)->toBe(\Prism\Prism\Enums\FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+});
+
 describe('Thinking parameter', function (): void {
     it('includes think parameter when thinking is enabled', function (): void {
         FixtureResponse::fakeResponseSequence('api/chat', 'ollama/text-with-thinking-enabled');
diff --git a/tests/Providers/OpenAI/StreamTest.php b/tests/Providers/OpenAI/StreamTest.php
index 0da5a3949..6a47f05aa 100644
--- a/tests/Providers/OpenAI/StreamTest.php
+++ b/tests/Providers/OpenAI/StreamTest.php
@@ -402,6 +402,40 @@
     Http::assertSent(fn (Request $request): bool => $request->data()['parallel_tool_calls'] === false);
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/responses', 'openai/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('openai', 'gpt-4o')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(\Prism\Prism\Enums\FinishReason::ToolCalls);
+    });
+});
+
 it('emits usage information', function (): void {
     FixtureResponse::fakeResponseSequence('v1/responses', 'openai/stream-basic-text-responses');
 
diff --git a/tests/Providers/OpenAI/StructuredWithToolsTest.php b/tests/Providers/OpenAI/StructuredWithToolsTest.php
index 7afd8910f..f0661be6a 100644
--- a/tests/Providers/OpenAI/StructuredWithToolsTest.php
+++ b/tests/Providers/OpenAI/StructuredWithToolsTest.php
@@ -148,6 +148,35 @@
         expect($response->steps)->toHaveCount(1);
     });
 
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/responses', 'openai/structured-with-client-executed-tool');
+
+        $schema = new ObjectSchema(
+            'output',
+            'the output object',
+            [new StringSchema('result', 'The result', true)],
+            ['result']
+        );
+
+        $tool = (new Tool)
+            ->as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::structured()
+            ->using(Provider::OpenAI, 'gpt-4o')
+            ->withSchema($schema)
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStructured();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+
     it('handles tool orchestration correctly with multiple tool types', function (): void {
         FixtureResponse::fakeResponseSequence('v1/responses', 'openai/structured-with-tool-orchestration');
 
diff --git a/tests/Providers/OpenAI/TextTest.php b/tests/Providers/OpenAI/TextTest.php
index b7fc8658d..25fe3e1c6 100644
--- a/tests/Providers/OpenAI/TextTest.php
+++ b/tests/Providers/OpenAI/TextTest.php
@@ -317,6 +317,28 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/responses', 'openai/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('openai', 'gpt-4o')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asText();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+});
+
 it('sets usage correctly with automatic caching', function (): void {
     FixtureResponse::fakeResponseSequence(
         'v1/responses',
diff --git a/tests/Providers/OpenRouter/StreamTest.php b/tests/Providers/OpenRouter/StreamTest.php
index 99925d1da..24d510820 100644
--- a/tests/Providers/OpenRouter/StreamTest.php
+++ b/tests/Providers/OpenRouter/StreamTest.php
@@ -243,6 +243,40 @@
     expect($streamEndEvents)->not->toBeEmpty();
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeStreamResponses('v1/chat/completions', 'openrouter/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::OpenRouter, 'openai/gpt-4-turbo')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(FinishReason::ToolCalls);
+    });
+});
+
 it('can handle reasoning/thinking tokens in streaming', function (): void {
     FixtureResponse::fakeStreamResponses('v1/chat/completions', 'openrouter/stream-text-with-reasoning');
 
diff --git a/tests/Providers/OpenRouter/TextTest.php b/tests/Providers/OpenRouter/TextTest.php
index 32a751716..ce09d4bb0 100644
--- a/tests/Providers/OpenRouter/TextTest.php
+++ b/tests/Providers/OpenRouter/TextTest.php
@@ -127,6 +127,28 @@
     expect($response->finishReason)->toBe(FinishReason::Stop);
 });
 
+describe('client-executed tools', function (): void {
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/chat/completions', 'openrouter/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::OpenRouter, 'openai/gpt-4-turbo')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->generate();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+});
+
 it('forwards advanced provider options to openrouter', function (): void {
     FixtureResponse::fakeResponseSequence('v1/chat/completions', 'openrouter/generate-text-with-a-prompt');
 
diff --git a/tests/Providers/XAI/StreamTest.php b/tests/Providers/XAI/StreamTest.php
index d4145ba92..4a8977a06 100644
--- a/tests/Providers/XAI/StreamTest.php
+++ b/tests/Providers/XAI/StreamTest.php
@@ -124,6 +124,40 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops streaming when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('v1/chat/completions', 'xai/stream-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using('xai', 'grok-4')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asStream();
+
+        $events = [];
+        $toolCallFound = false;
+
+        foreach ($response as $event) {
+            $events[] = $event;
+
+            if ($event instanceof ToolCallEvent) {
+                $toolCallFound = true;
+            }
+        }
+
+        expect($toolCallFound)->toBeTrue();
+
+        $lastEvent = end($events);
+        expect($lastEvent)->toBeInstanceOf(StreamEndEvent::class);
+        expect($lastEvent->finishReason)->toBe(FinishReason::ToolCalls);
+    });
+});
+
 it('handles max_tokens parameter correctly', function (): void {
     FixtureResponse::fakeResponseSequence('v1/chat/completions', 'xai/stream-basic-text-responses');
 
diff --git a/tests/Providers/XAI/XAITextTest.php b/tests/Providers/XAI/XAITextTest.php
index 5665b2c65..52a19a6a5 100644
--- a/tests/Providers/XAI/XAITextTest.php
+++ b/tests/Providers/XAI/XAITextTest.php
@@ -142,6 +142,28 @@
     });
 });
 
+describe('client-executed tools', function (): void {
+    it('stops execution when client-executed tool is called', function (): void {
+        FixtureResponse::fakeResponseSequence('chat/completions', 'xai/text-with-client-executed-tool');
+
+        $tool = Tool::as('client_tool')
+            ->for('A tool that executes on the client')
+            ->withStringParameter('input', 'Input parameter');
+
+        $response = Prism::text()
+            ->using(Provider::XAI, 'grok-beta')
+            ->withTools([$tool])
+            ->withMaxSteps(3)
+            ->withPrompt('Use the client tool')
+            ->asText();
+
+        expect($response->finishReason)->toBe(FinishReason::ToolCalls);
+        expect($response->toolCalls)->toHaveCount(1);
+        expect($response->toolCalls[0]->name)->toBe('client_tool');
+        expect($response->steps)->toHaveCount(1);
+    });
+});
+
 describe('Image support with XAI', function (): void {
     it('can send images from path', function (): void {
         FixtureResponse::fakeResponseSequence('chat/completions', 'xai/image-detection');
diff --git a/tests/ToolTest.php b/tests/ToolTest.php
index f7865ec8b..61abf4a67 100644
--- a/tests/ToolTest.php
+++ b/tests/ToolTest.php
@@ -181,3 +181,15 @@ public function __invoke(string $query): string
 
     $searchTool->handle('What time is the event?');
 });
+
+it('can throw a prism exception when handle is called on a tool without a handler', function (): void {
+    $tool = (new Tool)
+        ->as('client_tool')
+        ->for('A tool without a handler')
+        ->withParameter(new StringSchema('query', 'the search query'));
+
+    $this->expectException(PrismException::class);
+    $this->expectExceptionMessage('Tool (client_tool) has no handler defined');
+
+    $tool->handle('test');
+});