DeepSeek MCP Server

Implementation Reference

• src/index.ts:199-260 (handler)

  Handler function that processes arguments, calls DeepSeek chat completions API (with fallback to deepseek-chat model), and returns text content.

  async (args) => {
    let messages: ChatMessage[];
    if (args.message) {
      messages = [{ role: 'user', content: args.message }];
    } else if (args.messages) {
      messages = args.messages;
    } else {
      throw new Error("Either 'message' or 'messages' must be provided");
    }
  
    try {
      const response = await this.axiosInstance.post<DeepSeekResponse>(
        API_CONFIG.ENDPOINTS.CHAT,
        {
          messages,
          model: args.model,
          temperature: args.temperature,
          max_tokens: args.max_tokens,
          top_p: args.top_p,
          frequency_penalty: args.frequency_penalty,
          presence_penalty: args.presence_penalty
        }
      );
  
      return {
        content: [{
          type: "text",
          text: response.data.choices[0].message.content
        }]
      };
    } catch (error) {
      console.error("Error with deepseek-reasoner, falling back to deepseek-chat");
      
      try {
        const fallbackResponse = await this.axiosInstance.post<DeepSeekResponse>(
          API_CONFIG.ENDPOINTS.CHAT,
          {
            messages,
            model: 'deepseek-chat',
            temperature: args.temperature,
            max_tokens: args.max_tokens,
            top_p: args.top_p,
            frequency_penalty: args.frequency_penalty,
            presence_penalty: args.presence_penalty
          }
        );
  
        return {
          content: [{
            type: "text",
            text: "Note: Fallback to deepseek-chat due to reasoner error.\n\n" + 
                  fallbackResponse.data.choices[0].message.content
          }]
        };
      } catch (fallbackError) {
        if (axios.isAxiosError(fallbackError)) {
          throw new Error(`DeepSeek API error: ${fallbackError.response?.data?.error?.message ?? fallbackError.message}`);
        }
        throw fallbackError;
      }
    }
  }

• src/index.ts:187-198 (schema)

  Zod input schema defining parameters for the chat_completion tool, including message, model, and generation parameters.

    message: z.string().optional(),
    messages: z.array(z.object({
      role: z.enum(['system', 'user', 'assistant']),
      content: z.string()
    })).optional(),
    model: z.string().default('deepseek-reasoner'),
    temperature: z.number().min(0).max(2).default(0.7),
    max_tokens: z.number().positive().int().default(8000),
    top_p: z.number().min(0).max(1).default(1.0),
    frequency_penalty: z.number().min(-2).max(2).default(0.1),
    presence_penalty: z.number().min(-2).max(2).default(0)
  },

• src/index.ts:184-261 (registration)

  Registration of the chat_completion tool on the McpServer instance in the setupTools method.

  this.server.tool(
    "chat_completion",
    {
      message: z.string().optional(),
      messages: z.array(z.object({
        role: z.enum(['system', 'user', 'assistant']),
        content: z.string()
      })).optional(),
      model: z.string().default('deepseek-reasoner'),
      temperature: z.number().min(0).max(2).default(0.7),
      max_tokens: z.number().positive().int().default(8000),
      top_p: z.number().min(0).max(1).default(1.0),
      frequency_penalty: z.number().min(-2).max(2).default(0.1),
      presence_penalty: z.number().min(-2).max(2).default(0)
    },
    async (args) => {
      let messages: ChatMessage[];
      if (args.message) {
        messages = [{ role: 'user', content: args.message }];
      } else if (args.messages) {
        messages = args.messages;
      } else {
        throw new Error("Either 'message' or 'messages' must be provided");
      }
  
      try {
        const response = await this.axiosInstance.post<DeepSeekResponse>(
          API_CONFIG.ENDPOINTS.CHAT,
          {
            messages,
            model: args.model,
            temperature: args.temperature,
            max_tokens: args.max_tokens,
            top_p: args.top_p,
            frequency_penalty: args.frequency_penalty,
            presence_penalty: args.presence_penalty
          }
        );
  
        return {
          content: [{
            type: "text",
            text: response.data.choices[0].message.content
          }]
        };
      } catch (error) {
        console.error("Error with deepseek-reasoner, falling back to deepseek-chat");
        
        try {
          const fallbackResponse = await this.axiosInstance.post<DeepSeekResponse>(
            API_CONFIG.ENDPOINTS.CHAT,
            {
              messages,
              model: 'deepseek-chat',
              temperature: args.temperature,
              max_tokens: args.max_tokens,
              top_p: args.top_p,
              frequency_penalty: args.frequency_penalty,
              presence_penalty: args.presence_penalty
            }
          );
  
          return {
            content: [{
              type: "text",
              text: "Note: Fallback to deepseek-chat due to reasoner error.\n\n" + 
                    fallbackResponse.data.choices[0].message.content
            }]
          };
        } catch (fallbackError) {
          if (axios.isAxiosError(fallbackError)) {
            throw new Error(`DeepSeek API error: ${fallbackError.response?.data?.error?.message ?? fallbackError.message}`);
          }
          throw fallbackError;
        }
      }
    }
  );