Your AI assistant, now fluent in mainframe.

What it does

AI assistants often write JCL or DFSORT statements that look right but fail. MainframeKit gives your assistant the same rule-based checks this site uses, so it can catch the mistake before you submit the job.

Tool	What your assistant can do with it
check_jcl	Find common JCL mistakes and explain every JOB, EXEC and DD statement in plain English.
explain_dfsort	Explain SORT, INCLUDE/OMIT, INREC/OUTREC and SUM statements and flag problems.
lookup_code	Explain 161 abends, SQLCODEs, CICS and MQ codes: causes, fixes, IBM sources and the matching lesson.
copybook_layout	Start, length and type of every copybook field, and the record length.

Ready-made prompts: Review my JCL, Explain this abend and Build a sort step.

Try asking

• "Write JCL to copy MY.INPUT to a new data set, then check it with MainframeKit."
• "My batch job ended with S0C7 after the payroll step. What should I check first?"
• "Here is my copybook. At which position does CUST-BAL start, and how long is the record?"

Set it up

You need Node.js 18 or later. Then add MainframeKit to your assistant's MCP settings:

Claude Desktop (Settings → Developer → Edit config) or Cursor (Settings → MCP):

{
  "mcpServers": {
    "mainframekit": { "command": "npx", "args": ["-y", "mainframekit-mcp"] }
  }
}

Claude Code:

claude mcp add mainframekit -- npx -y mainframekit-mcp

VS Code (GitHub Copilot agent mode): add to .vscode/mcp.json:

{
  "servers": {
    "mainframekit": { "type": "stdio", "command": "npx", "args": ["-y", "mainframekit-mcp"] }
  }
}

Private by design

• It runs on your PC. It makes no network requests and connects to no mainframe, so your code never leaves your machine.
• No login, no account, no tracking, no AI tokens: your own assistant does the talking, MainframeKit only runs its rules.
• The same input always gives the same answer. Every rule comes from IBM documentation.

Good to know

• Works alongside IBM and Broadcom tools; it does not replace them or connect to z/OS.
• Free to use for personal and work purposes; see the licence in the package. Always confirm against IBM documentation before changing production.
• Package: mainframekit-mcp on npm.