Hopper
The first agentic development environment for the mainframe.
An agent built for the mainframe.
Hopper edits JCL with the column-positional formatting JES expects, drives ISPF by panel ID and option codes, composes RACF commands like PERMIT and RDEFINE, and parses JESMSGLG and SYSUDUMP as structured data. The MCP tools are mainframe primitives, not shell wrappers.
Compile, test, ship — in one prompt.
Edit a COBOL member, then ask the agent to submit the compile-link JCL, run the test transaction, and roll the load module into CICS. Hopper handles the JES return codes, the JCL overrides, and the CICS NEWCOPY. You review the diff and approve the rollout.
Skip the SDSF rabbit hole.
Tag a failed JOBID with @. The agent reads JESMSGLG, JESYSMSG, and SYSUDUMP, then names the abend code, the failing step, and the source line that triggered it. The terminal opens to that step so you can confirm what it found.
Drive it yourself, anytime.
Hopper embeds a TN3270 emulator with PF, PA, and attention-key support, multiple sessions, and copy-paste against any panel. Type commands directly. The agent runs in the same window but does nothing until you ask it.
