/mainframe-removal

name: mainframe-removal
description: Apply mainframe dependency transformations to COBOL code using a pre-generated transformation guide. Converts CICS/VSAM constructs to standard COBOL.
license: MIT
compatibility: Requires GnuCOBOL (cobc) for verification
triggers:
  - remove mainframe
  - cobol transformation
  - cics removal
  - standard cobol

Apply the transformations from a transformation guide to convert mainframe-specific COBOL to standard COBOL.

**Prerequisite**: A transformation guide must exist (see `cobol-mainframe-planning` skill).

Transformation Requirements

Data Operations

• Replace each CICS/VSAM construct with its standard COBOL equivalent per the plan
• Add FILE STATUS checks after EVERY file operation:
• Check for success (00) before proceeding
• Handle "not found" (23) distinctly from I/O errors (3x)
• Handle "file not exists" (35) at OPEN time
• Add explicit CLOSE statements in all code paths (including error paths)

UI/Terminal Operations (BMS maps, SEND/RECEIVE)

• Replace with simple stubs or ACCEPT/DISPLAY statements
• Do NOT spend time replicating screen layouts
• Focus on preserving data flow, not UI fidelity

Error Handling

• Replace CICS RESP/RESP2 checks with equivalent FILE STATUS logic
• Replace HANDLE CONDITION with explicit status checking after operations
• Ensure error paths don't leave files open

See [references/cics-transformation-examples.md](references/cics-transformation-examples.md) for before/after code examples.

Verification

After transformation:

• Code MUST compile without errors
• Test with valid input → should execute core business logic
• Test with missing/invalid files → should fail gracefully, not crash

Preserve

• All original business logic
• Data transformations and calculations
• Validation rules

Checklist

• [ ] All EXEC CICS commands replaced
• [ ] FILE STATUS declared for all files
• [ ] FILE STATUS checked after every I/O operation
• [ ] CLOSE statements in all code paths
• [ ] Code compiles successfully
• [ ] Basic test execution passes