Introducing Hopper

Documentation Index

Fetch the complete documentation index at: https://docs.hypercubic.ai/llms.txt

Use this file to discover all available pages before exploring further.

Hopper is an AI-powered development environment for IBM z/OS engineers and developers. It understands your mainframe (datasets, JCL, COBOL, and CICS) and works across multiple subsystems to ship features, fix failed batch jobs, and triage production incidents. Four panels share one mainframe session:

1. A TN3270 terminal. A clickable, copy-pasteable rendering of the mainframe’s 24×80 green-screen interface.
2. A datasets browser. Filter, click, and preview mainframe files inline without typing IDCAMS commands.
3. A jobs browser. Watch JES queue entries change status in real time without opening SDSF.
4. A chat agent. A panel that runs alongside the terminal. It reads source, submits jobs, decodes records, and writes changes under your supervision.

Hopper connects to your z/OS system over standard FTP and TN3270. There is no agent installed on the mainframe. Everything runs on your laptop. You don’t need to be a mainframe expert to do mainframe work with Hopper. Either way, you’ll ship more with it than without it.

​

Start here

​

What it’s for

Mainframes run core systems at most large banks, insurers, governments, and airlines. They use a 1970s block-mode terminal, JCL, and EBCDIC fixed-format files. Modern tooling expects HTTP, JSON, and UTF-8. Hopper bridges that gap. Common requests and what Hopper does to satisfy them:

​

What the chat agent does

You ask in plain English. The agent picks the right operations and runs them.

• “Show me what CBACT01C does.” It reads the COBOL from the source PDS and walks you through it.
• “This job failed last night — what happened?” It pulls the spool, classifies the abend, points at the offending step.
• “Add a check for negative balances to the validation paragraph.” It reads, edits, recompiles, reports back. You approve before any write.
• “How many accounts have a balance over $1M?” It snapshots the VSAM file, decodes via copybook, runs SQL.

Mutating actions — writing a dataset, submitting a job, modifying CICS resources — pause for your approval. The agent shows the exact change. You approve or reject. See Tools.

​

Who uses it

• Mainframe developers who want a modern interface and an AI assistant that understands JCL, COBOL, and CICS.
• Engineers onboarding to a mainframe codebase, who need to read and reason about old code without years of context.
• Modernization teams encapsulating mainframe systems behind modern APIs.

​

Where it fits in modernization

Mainframe modernization usually means rehosting, rewriting, refactoring, or encapsulating. Hopper is for the encapsulating phase: read what’s running, understand the data, test interactions before you commit to a direction. It does not migrate, rewrite, or translate COBOL.

​

What Hopper doesn’t do

• No mainframe-side install. The product runs on your laptop.
• No bulk data movement. Hopper reads and writes datasets; it doesn’t move data between systems.
• No production change management. The deploy feature targets dev and test environments.

​

Learn the basics

​

New to mainframes?

If you’ve never seen TN3270, JCL, or EBCDIC, start with How Hopper works. The chat agent can also explain the screen you’re on — paste or attach it and ask.