feat: implement Ollama provider for LLM abstraction

Author: bhouston

packages/agent/src/core/llm/provider.ts

@@ -3,6 +3,7 @@
  */
 
 import { AnthropicProvider } from './providers/anthropic.js';
+import { OllamaProvider } from './providers/ollama.js';
 import { ProviderOptions, GenerateOptions, LLMResponse } from './types.js';
 
 /**
@@ -39,6 +40,7 @@ const providerFactories: Record<
   (model: string, options: ProviderOptions) => LLMProvider
 > = {
   anthropic: (model, options) => new AnthropicProvider(model, options),
+  ollama: (model, options) => new OllamaProvider(model, options),
 };
 
 /**

packages/agent/src/core/llm/providers/ollama.ts

@@ -0,0 +1,157 @@
+/**
+ * Ollama provider implementation
+ */
+
+import { TokenUsage } from '../../tokens.js';
+import { LLMProvider } from '../provider.js';
+import {
+  GenerateOptions,
+  LLMResponse,
+  Message,
+  ProviderOptions,
+} from '../types.js';
+
+/**
+ * Ollama-specific options
+ */
+export interface OllamaOptions extends ProviderOptions {
+  baseUrl?: string;
+}
+
+/**
+ * Ollama provider implementation
+ */
+export class OllamaProvider implements LLMProvider {
+  name: string = 'ollama';
+  provider: string = 'ollama.chat';
+  model: string;
+  private baseUrl: string;
+
+  constructor(model: string, options: OllamaOptions = {}) {
+    this.model = model;
+    this.baseUrl = options.baseUrl || process.env.OLLAMA_BASE_URL || 'http://localhost:11434';
+
+    // Ensure baseUrl doesn't end with a slash
+    if (this.baseUrl.endsWith('/')) {
+      this.baseUrl = this.baseUrl.slice(0, -1);
+    }
+  }
+
+  /**
+   * Generate text using Ollama API
+   */
+  async generateText(options: GenerateOptions): Promise<LLMResponse> {
+    const { messages, functions, temperature = 0.7, maxTokens, topP, frequencyPenalty, presencePenalty } = options;
+
+    // Format messages for Ollama API
+    const formattedMessages = this.formatMessages(messages);
+
+    try {
+      // Prepare request options
+      const requestOptions: any = {
+        model: this.model,
+        messages: formattedMessages,
+        stream: false,
+        options: {
+          temperature: temperature,
+          // Ollama uses top_k instead of top_p, but we'll include top_p if provided
+          ...(topP !== undefined && { top_p: topP }),
+          ...(frequencyPenalty !== undefined && { frequency_penalty: frequencyPenalty }),
+          ...(presencePenalty !== undefined && { presence_penalty: presencePenalty }),
+        },
+      };
+
+      // Add max_tokens if provided
+      if (maxTokens !== undefined) {
+        requestOptions.options.num_predict = maxTokens;
+      }
+
+      // Add functions/tools if provided
+      if (functions && functions.length > 0) {
+        requestOptions.tools = functions.map((fn) => ({
+          name: fn.name,
+          description: fn.description,
+          parameters: fn.parameters,
+        }));
+      }
+
+      // Make the API request
+      const response = await fetch(`${this.baseUrl}/api/chat`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify(requestOptions),
+      });
+
+      if (!response.ok) {
+        const errorText = await response.text();
+        throw new Error(`Ollama API error: ${response.status} ${errorText}`);
+      }
+
+      const data = await response.json();
+
+      // Extract content and tool calls
+      const content = data.message?.content || '';
+      const toolCalls = data.message?.tool_calls?.map((toolCall: any) => ({
+        id: toolCall.id || `tool-${Date.now()}-${Math.random().toString(36).substring(2, 11)}`,
+        name: toolCall.name,
+        content: JSON.stringify(toolCall.args || toolCall.arguments || {}),
+      })) || [];
+
+      // Create token usage from response data
+      const tokenUsage = new TokenUsage();
+      tokenUsage.input = data.prompt_eval_count || 0;
+      tokenUsage.output = data.eval_count || 0;
+
+      return {
+        text: content,
+        toolCalls: toolCalls,
+        tokenUsage: tokenUsage,
+      };
+    } catch (error) {
+      throw new Error(
+        `Error calling Ollama API: ${(error as Error).message}`,
+      );
+    }
+  }
+
+  /**
+   * Format messages for Ollama API
+   */
+  private formatMessages(messages: Message[]): any[] {
+    return messages.map((msg) => {
+      if (msg.role === 'user' || msg.role === 'assistant' || msg.role === 'system') {
+        return {
+          role: msg.role,
+          content: msg.content,
+        };
+      } else if (msg.role === 'tool_result') {
+        // Ollama expects tool results as a 'tool' role
+        return {
+          role: 'tool',
+          content: msg.content,
+          tool_call_id: msg.tool_use_id,
+        };
+      } else if (msg.role === 'tool_use') {
+        // We'll convert tool_use to assistant messages with tool_calls
+        return {
+          role: 'assistant',
+          content: '',
+          tool_calls: [
+            {
+              id: msg.id,
+              name: msg.name,
+              arguments: msg.content,
+            },
+          ],
+        };
+      }
+      // Default fallback
+      return {
+        role: 'user',
+        content: msg.content,
+      };
+    });
+  }
+}