Ollama MCP Server

Instructions

Implementation Reference

• src/index.ts:471-536 (handler)

  The handler function that implements the core logic of the chat_completion tool. Converts messages to a prompt, calls Ollama generate API, and returns formatted OpenAI-compatible response.

  private async handleChatCompletion(args: any) {
    try {
      // Convert chat messages to a single prompt
      const prompt = args.messages
        .map((msg: any) => {
          switch (msg.role) {
            case 'system':
              return `System: ${msg.content}\n`;
            case 'user':
              return `User: ${msg.content}\n`;
            case 'assistant':
              return `Assistant: ${msg.content}\n`;
            default:
              return '';
          }
        })
        .join('');
  
      // Make request to Ollama API with configurable timeout and raw mode
      const response = await axios.post<OllamaGenerateResponse>(
        `${OLLAMA_HOST}/api/generate`,
        {
          model: args.model,
          prompt,
          stream: false,
          temperature: args.temperature,
          raw: true, // Add raw mode for more direct responses
        },
        {
          timeout: args.timeout || DEFAULT_TIMEOUT,
        }
      );
  
      return {
        content: [
          {
            type: 'text',
            text: JSON.stringify({
              id: 'chatcmpl-' + Date.now(),
              object: 'chat.completion',
              created: Math.floor(Date.now() / 1000),
              model: args.model,
              choices: [
                {
                  index: 0,
                  message: {
                    role: 'assistant',
                    content: response.data.response,
                  },
                  finish_reason: 'stop',
                },
              ],
            }, null, 2),
          },
        ],
      };
    } catch (error) {
      if (axios.isAxiosError(error)) {
        throw new McpError(
          ErrorCode.InternalError,
          `Ollama API error: ${error.response?.data?.error || error.message}`
        );
      }
      throw new McpError(ErrorCode.InternalError, `Unexpected error: ${formatError(error)}`);
    }
  }

• src/index.ts:210-248 (schema)

  Input schema definition for the chat_completion tool, specifying parameters like model, messages, temperature, and timeout.

  inputSchema: {
    type: 'object',
    properties: {
      model: {
        type: 'string',
        description: 'Name of the Ollama model to use',
      },
      messages: {
        type: 'array',
        items: {
          type: 'object',
          properties: {
            role: {
              type: 'string',
              enum: ['system', 'user', 'assistant'],
            },
            content: {
              type: 'string',
            },
          },
          required: ['role', 'content'],
        },
        description: 'Array of messages in the conversation',
      },
      temperature: {
        type: 'number',
        description: 'Sampling temperature (0-2)',
        minimum: 0,
        maximum: 2,
      },
      timeout: {
        type: 'number',
        description: 'Timeout in milliseconds (default: 60000)',
        minimum: 1000,
      },
    },
    required: ['model', 'messages'],
    additionalProperties: false,
  },

• src/index.ts:207-249 (registration)

  Registration of the chat_completion tool in the ListTools response, including name, description, and input schema.

  {
    name: 'chat_completion',
    description: 'OpenAI-compatible chat completion API',
    inputSchema: {
      type: 'object',
      properties: {
        model: {
          type: 'string',
          description: 'Name of the Ollama model to use',
        },
        messages: {
          type: 'array',
          items: {
            type: 'object',
            properties: {
              role: {
                type: 'string',
                enum: ['system', 'user', 'assistant'],
              },
              content: {
                type: 'string',
              },
            },
            required: ['role', 'content'],
          },
          description: 'Array of messages in the conversation',
        },
        temperature: {
          type: 'number',
          description: 'Sampling temperature (0-2)',
          minimum: 0,
          maximum: 2,
        },
        timeout: {
          type: 'number',
          description: 'Timeout in milliseconds (default: 60000)',
          minimum: 1000,
        },
      },
      required: ['model', 'messages'],
      additionalProperties: false,
    },
  },

• src/index.ts:274-275 (registration)

  Dispatch in CallToolRequestHandler switch statement that routes chat_completion calls to the handler function.

  case 'chat_completion':
    return await this.handleChatCompletion(request.params.arguments);