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Cobol Legacy Ledger

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Description

Learn COBOL through a live banking system — 18 programs, 6-node settlement network, real-time simulation, Python read/write bridge, SHA-256 tamper detection, AI tutor (Ollama + Claude), static analysis with orthogonal call graphs, and a glass morphism web console. 800 tests.

Installation

This entry records only its repository, not the path inside it, so there is no exact command to give. Open the source below and copy the folder into ~/.claude/skills/, or the file into ~/.claude/agents/.

README

COBOL Legacy Ledger

[![Live Demo](https://img.shields.io/badge/%F0%9F%9A%80_Live_Demo-Try_It_Now-blue?style=for-the-badge)](https://cobol-legacy-ledger-production.up.railway.app/console/)

[![CI](https://github.com/albertdobmeyer/cobol-legacy-ledger/actions/workflows/ci.yml/badge.svg)](https://github.com/albertdobmeyer/cobol-legacy-ledger/actions/workflows/ci.yml) ![Python 3.9+](https://img.shields.io/badge/python-3.9%2B-blue) ![License: MIT](https://img.shields.io/badge/license-MIT-green) ![Tests: 820](https://img.shields.io/badge/tests-820%20passing-brightgreen) ![COBOL Programs: 18](https://img.shields.io/badge/COBOL-18%20programs-purple) ![Nodes: 6](https://img.shields.io/badge/nodes-6%20banks-orange)

**Learn COBOL through a live banking system** — run simulations, corrupt ledgers, catch fraud with SHA-256 hash chains, and explore spaghetti code with AI-powered static analysis.

"COBOL isn't the problem. Lack of observability is."

This is a fully functional **6-node inter-bank settlement system** in COBOL, wrapped with a Python read/write bridge that adds cryptographic integrity without modifying a single line of legacy code. An AI tutor (Ollama local or Claude cloud) can explain any paragraph, trace execution paths, and compare spaghetti vs clean code side by side. Every source file teaches COBOL syntax, banking concepts, and integration patterns inline.

At a Glance

**Stack**: COBOL (GnuCOBOL) · Python 3.9+ · FastAPI · SQLite · Vanilla JS · Docker

  • 18 COBOL programs (10 clean + 8 intentional spaghetti) with a Python observation layer — no legacy code modified
  • SHA-256 hash chain integrity across 6 independent banking nodes, with live tamper detection in <100ms
  • 807 automated tests (unit, integration, E2E browser), CI with linting, multi-version Python matrix
  • AI-powered static analysis — call graphs, dead code detection, complexity scoring, cross-file dependency mapping

**See it in action**: Run `pytho