BobMigrate — Autonomous Codebase Modernization

The Problem Upgrading legacy Python codebases is a time-intensive, error-prone process. A typical Pydantic v1 → v2 migration requires an engineer to: Read and internalize 30+ pages of framework migration documentation Locate every deprecated pattern across dozens of model files (@validator, .dict(), class Config, regex=, min_items=, orm_mode, etc.) Manually rewrite each occurrence with the correct v2 equivalent — in the right order, with the right decorator stacking Fix a broken Flask service layer simultaneously, migrating routes, request parsing, error handling, and header injection to FastAPI conventions Debug cascading test failures introduced by subtle API differences until the suite is green again This process routinely costs multiple engineer-days and introduces regressions. It is mechanical, repetitive, and entirely automatable — yet no tool has done it end-to-end until now. The Solution BobMigrate is an autonomous modernization agent built natively inside IBM Bob IDE. It treats a legacy codebase as a structured transformation problem: ingest the migration specification, decompose the work across parallel subagents, apply changes atomically to disk, and close the loop via an agentic CLI test harness — all without human intervention. The result: 3 source files, 28 migration rules, 1 syntax error corrected, 6/6 tests passing, 0 mypy errors — in a single orchestration pass.