Ollama MCP Server

Instructions

Implementation Reference

• src/index.ts:207-238 (handler)

  Handler function that executes the chat_completion tool logic: calls ollama.chat with provided parameters and returns an OpenAI-compatible chat completion JSON response.

  async ({ model, messages, temperature, think }) => {
    try {
      const response = await ollama.chat({
        model,
        messages,
        options: { temperature },
        ...(think !== undefined ? { think } : {}),
      });
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify({
              id: "chatcmpl-" + Date.now(),
              object: "chat.completion",
              created: Math.floor(Date.now() / 1000),
              model,
              choices: [
                {
                  index: 0,
                  message: response.message,
                  finish_reason: "stop",
                },
              ],
            }, null, 2),
          },
        ],
      };
    } catch (error) {
      return { content: [{ type: "text", text: `Error: ${formatError(error)}` }], isError: true };
    }
  }

• src/index.ts:191-239 (registration)

  Registration of the 'chat_completion' tool using McpServer.registerTool, including schema and handler.

  server.registerTool(
    "chat_completion",
    {
      title: "Chat completion",
      description: "OpenAI-compatible chat completion API. Supports optional images per message for vision/multimodal models.",
      inputSchema: {
        model: z.string(),
        messages: z.array(z.object({
          role: z.enum(["system", "user", "assistant"]),
          content: z.string(),
          images: z.array(z.string()).optional(), // Array of image paths
        })),
        temperature: z.number().min(0).max(2).optional(),
        think: z.boolean().optional(),
      },
    },
    async ({ model, messages, temperature, think }) => {
      try {
        const response = await ollama.chat({
          model,
          messages,
          options: { temperature },
          ...(think !== undefined ? { think } : {}),
        });
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify({
                id: "chatcmpl-" + Date.now(),
                object: "chat.completion",
                created: Math.floor(Date.now() / 1000),
                model,
                choices: [
                  {
                    index: 0,
                    message: response.message,
                    finish_reason: "stop",
                  },
                ],
              }, null, 2),
            },
          ],
        };
      } catch (error) {
        return { content: [{ type: "text", text: `Error: ${formatError(error)}` }], isError: true };
      }
    }
  );

• src/index.ts:196-205 (schema)

  Zod input schema definition for the chat_completion tool, validating model, messages (with optional images), temperature, and think parameters.

  inputSchema: {
    model: z.string(),
    messages: z.array(z.object({
      role: z.enum(["system", "user", "assistant"]),
      content: z.string(),
      images: z.array(z.string()).optional(), // Array of image paths
    })),
    temperature: z.number().min(0).max(2).optional(),
    think: z.boolean().optional(),
  },