feat(provider.ollama): add native tool calling support for Ollama API

- Add IOllamaTool and IOllamaToolCall types for native function calling
- Add think parameter to IOllamaModelOptions for reasoning models (GPT-OSS, QwQ)
- Add tools parameter to IOllamaChatOptions
- Add toolCalls to response interfaces (IOllamaStreamChunk, IOllamaChatResponse)
- Update chat(), chatStreamResponse(), collectStreamResponse(), chatWithOptions() to support native tools
- Parse tool_calls from Ollama API responses
- Add support for tool message role in conversation history

ts/provider.ollama.ts

@@ -26,6 +26,39 @@ export interface IOllamaModelOptions {
   num_predict?: number;   // Max tokens to predict
   stop?: string[];        // Stop sequences
   seed?: number;          // Random seed for reproducibility
+  think?: boolean;        // Enable thinking/reasoning mode (for GPT-OSS, QwQ, etc.)
+}
+
+/**
+ * JSON Schema tool definition for Ollama native tool calling
+ * @see https://docs.ollama.com/capabilities/tool-calling
+ */
+export interface IOllamaTool {
+  type: 'function';
+  function: {
+    name: string;
+    description: string;
+    parameters: {
+      type: 'object';
+      properties: Record<string, {
+        type: string;
+        description?: string;
+        enum?: string[];
+      }>;
+      required?: string[];
+    };
+  };
+}
+
+/**
+ * Tool call returned by model in native tool calling mode
+ */
+export interface IOllamaToolCall {
+  function: {
+    name: string;
+    arguments: Record<string, unknown>;
+    index?: number;
+  };
 }
 
 export interface IOllamaProviderOptions {
@@ -43,6 +76,7 @@ export interface IOllamaChatOptions extends ChatOptions {
   options?: IOllamaModelOptions;  // Per-request model options
   timeout?: number;               // Per-request timeout in ms
   model?: string;                 // Per-request model override
+  tools?: IOllamaTool[];          // Available tools for native function calling
   // images is inherited from ChatOptions
 }
 
@@ -52,6 +86,7 @@ export interface IOllamaChatOptions extends ChatOptions {
 export interface IOllamaStreamChunk {
   content: string;
   thinking?: string;  // For models with extended thinking
+  toolCalls?: IOllamaToolCall[];  // Tool calls in streaming mode
   done: boolean;
   stats?: {
     totalDuration?: number;
@@ -64,6 +99,7 @@ export interface IOllamaStreamChunk {
  */
 export interface IOllamaChatResponse extends ChatResponse {
   thinking?: string;
+  toolCalls?: IOllamaToolCall[];  // Tool calls from model (native tool calling)
   stats?: {
     totalDuration?: number;
     evalCount?: number;
@@ -233,18 +269,26 @@ export class OllamaProvider extends MultiModalModel {
       userMessage,
     ];
 
+    // Build request body - include think parameter if set
+    const requestBody: Record<string, unknown> = {
+      model: this.model,
+      messages: messages,
+      stream: false,
+      options: this.defaultOptions,
+    };
+
+    // Add think parameter for reasoning models (GPT-OSS, QwQ, etc.)
+    if (this.defaultOptions.think !== undefined) {
+      requestBody.think = this.defaultOptions.think;
+    }
+
     // Make API call to Ollama with defaultOptions and timeout
     const response = await fetch(`${this.baseUrl}/api/chat`, {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
       },
-      body: JSON.stringify({
+      body: JSON.stringify(requestBody),
-        model: this.model,
-        messages: messages,
-        stream: false,
-        options: this.defaultOptions,
-      }),
       signal: AbortSignal.timeout(this.defaultTimeout),
     });
 
@@ -331,15 +375,28 @@ export class OllamaProvider extends MultiModalModel {
       userMessage,
     ];
 
+    // Build request body with optional tools and think parameters
+    const requestBody: Record<string, unknown> = {
+      model,
+      messages,
+      stream: true,
+      options: modelOptions,
+    };
+
+    // Add think parameter for reasoning models (GPT-OSS, QwQ, etc.)
+    if (modelOptions.think !== undefined) {
+      requestBody.think = modelOptions.think;
+    }
+
+    // Add tools for native function calling
+    if (optionsArg.tools && optionsArg.tools.length > 0) {
+      requestBody.tools = optionsArg.tools;
+    }
+
     const response = await fetch(`${this.baseUrl}/api/chat`, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({
+      body: JSON.stringify(requestBody),
-        model,
-        messages,
-        stream: true,
-        options: modelOptions,
-      }),
       signal: AbortSignal.timeout(timeout),
     });
 
@@ -364,9 +421,25 @@ export class OllamaProvider extends MultiModalModel {
               if (!line.trim()) continue;
               try {
                 const json = JSON.parse(line);
+
+                // Parse tool_calls from response
+                let toolCalls: IOllamaToolCall[] | undefined;
+                if (json.message?.tool_calls && Array.isArray(json.message.tool_calls)) {
+                  toolCalls = json.message.tool_calls.map((tc: any) => ({
+                    function: {
+                      name: tc.function?.name || '',
+                      arguments: typeof tc.function?.arguments === 'string'
+                        ? JSON.parse(tc.function.arguments)
+                        : tc.function?.arguments || {},
+                      index: tc.index,
+                    },
+                  }));
+                }
+
                 yield {
                   content: json.message?.content || '',
                   thinking: json.message?.thinking,
+                  toolCalls,
                   done: json.done || false,
                   stats: json.done ? {
                     totalDuration: json.total_duration,
@@ -393,11 +466,13 @@ export class OllamaProvider extends MultiModalModel {
     const stream = await this.chatStreamResponse(optionsArg);
     let content = '';
     let thinking = '';
+    let toolCalls: IOllamaToolCall[] = [];
     let stats: IOllamaChatResponse['stats'];
 
     for await (const chunk of stream) {
       if (chunk.content) content += chunk.content;
       if (chunk.thinking) thinking += chunk.thinking;
+      if (chunk.toolCalls) toolCalls = toolCalls.concat(chunk.toolCalls);
       if (chunk.stats) stats = chunk.stats;
       if (onChunk) onChunk(chunk);
     }
@@ -406,6 +481,7 @@ export class OllamaProvider extends MultiModalModel {
       role: 'assistant' as const,
       message: content,
       thinking: thinking || undefined,
+      toolCalls: toolCalls.length > 0 ? toolCalls : undefined,
       stats,
     };
   }
@@ -418,8 +494,17 @@ export class OllamaProvider extends MultiModalModel {
     const timeout = optionsArg.timeout || this.defaultTimeout;
     const modelOptions = { ...this.defaultOptions, ...optionsArg.options };
 
-    // Format history messages with optional images and reasoning
+    // Format history messages with optional images, reasoning, and tool role
     const historyMessages = optionsArg.messageHistory.map((msg) => {
+      // Handle tool result messages
+      if ((msg as any).role === 'tool') {
+        return {
+          role: 'tool',
+          content: msg.content,
+          tool_name: (msg as any).toolName,
+        };
+      }
+
       const formatted: { role: string; content: string; images?: string[]; reasoning?: string } = {
         role: msg.role,
         content: msg.content,
@@ -448,15 +533,28 @@ export class OllamaProvider extends MultiModalModel {
       userMessage,
     ];
 
+    // Build request body with optional tools and think parameters
+    const requestBody: Record<string, unknown> = {
+      model,
+      messages,
+      stream: false,
+      options: modelOptions,
+    };
+
+    // Add think parameter for reasoning models (GPT-OSS, QwQ, etc.)
+    if (modelOptions.think !== undefined) {
+      requestBody.think = modelOptions.think;
+    }
+
+    // Add tools for native function calling
+    if (optionsArg.tools && optionsArg.tools.length > 0) {
+      requestBody.tools = optionsArg.tools;
+    }
+
     const response = await fetch(`${this.baseUrl}/api/chat`, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({
+      body: JSON.stringify(requestBody),
-        model,
-        messages,
-        stream: false,
-        options: modelOptions,
-      }),
       signal: AbortSignal.timeout(timeout),
     });
 
@@ -465,10 +563,26 @@ export class OllamaProvider extends MultiModalModel {
     }
 
     const result = await response.json();
+
+    // Parse tool_calls from response
+    let toolCalls: IOllamaToolCall[] | undefined;
+    if (result.message?.tool_calls && Array.isArray(result.message.tool_calls)) {
+      toolCalls = result.message.tool_calls.map((tc: any) => ({
+        function: {
+          name: tc.function?.name || '',
+          arguments: typeof tc.function?.arguments === 'string'
+            ? JSON.parse(tc.function.arguments)
+            : tc.function?.arguments || {},
+          index: tc.index,
+        },
+      }));
+    }
+
     return {
       role: 'assistant' as const,
-      message: result.message.content,
+      message: result.message.content || '',
       thinking: result.message.thinking,
+      toolCalls,
       stats: {
         totalDuration: result.total_duration,
         evalCount: result.eval_count,