IBM AS/400 ISeries MCP Server

This project implements a customizable MCP server to execute RTE protocol.

Example

Development

Requirements

• Java 21+*

Run

• Compile project ./mvnw clean package

• Run server on SSE mode

  java -jar target/rte-mcp-server-0.0.1-SNAPSHOT.jar
  

• Run server on STDIO mode

  java -jar -Dspring.ai.mcp.server.stdio=true rte-mcp-server-0.0.1-SNAPSHOT.jar
  

RteUtils

The intention of this project is to be easily extensible. You can add your own MCP tools by using RteUtils class.

Also is needed to define the RTE connection parameters and the RTE flow in a yaml format.

RteUtils has the following methods implemented:

• static RteProtocolClient connect(RteConfig config): Connects to the RTE server using the provided yaml.
• static String executeSteps(RteProtocolClient client, List<RteStep> steps): Executes the provided steps on the RTE server and returns the screen result as a string using the provided yaml.

The method exposed as MCP tool should be annotated as @Tool and the class should be annotated as @Services like in the followig example:

@Service
public class RteServiceLoginTool implements RteTool {

  private static final Logger logger = LoggerFactory.getLogger(RteServiceLoginTool.class);

  @Tool(description = "Execute an RTE transaction in a given server", name = "TN5250 Login")
  public String executeRteTransaction(String server, int port) {
    try {
      RteFlow flow = RteYamlLoader.load("/flow.yaml");
      RteProtocolClient client = RteTool.connect(flow.getConfig(), server, port);
      return RteTool.executeSteps(client, flow.getSteps());
    } catch (IOException | RteIOException | InterruptedException | TimeoutException e) {
      logger.error("Error executing RTE flow", e);
      return "Error executing RTE flow: " + e.getMessage();
    }
  }
}

The yaml defines the connection parameters and the steps to execute in the RTE server. This * yaml* file should have the following structure

config:
  server: localhost
  port: 2324
  protocol: TN5250
  terminalType: 'IBM-3477-FC: 27x132'
  sslType: None

steps:
  - actions:
      - label: User
        input: TESTUSR
      - label: Password
        input: TESTPSW
    attentionKey: ENTER

Any number the steps can be defined in the yaml file.

• server: The server address to connect to the RTE server.

• port: The port to connect to the RTE server.

• protocol: The supported protocols are TN5250, TN3270 and VT420

• terminalType: The following table shows the supported terminal types for each protocol:

  Protocol	Terminal Type
  TN5250	IBM-3477-FC: 27x132
  	IBM-3179-2: 24x80
  TN3270	IBM-3278-M2: 24x80
  	IBM-3278-M2-E: 24x80
  	IBM-3278-M3: 32x80
  	IBM-3278-M3-E: 32x80
  	IBM-3278-M4: 43x80
  	IBM-3278-M4-E: 43x80
  	IBM-3278-M5: 27x132
  	IBM-3278-M5-E: 27x132
  VT420	VT420-7: 24x80

• sslType: The supported ssl types are None TLS and SSLv3.

• steps: A list of actions representing the steps to execute in the RTE server.

• actions: All the actions to execute in the current screen, any number of pairs label/input could be added.

  • label: The label of the field to fill in the RTE screen.
  • input: The value to fill in the field.
  • attentionKey: The key to press after filling the fields, it can be ENTER, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, F13, F14, F15, F16, F17, F18, F19, F20, F21, F22, F23, F24, ATTN, CLEAR, SYSRQ, RESET, ROLL_UP, ROLL_DN, PA1, PA2 or PA3.

Testing

An example of integration test is provided in the RteServiceLoginToolTest class, this test uses the MCPClient validate the list of tools and execute it.

note: to test the behaving of to tool is recommended to generate a dump of the RTE flow to be executed and mock it using wiresham

More information on how to test and debug the server could be found here