AI agents have fundamentally changed the economics of legacy migration by automating the mechanical 80% of the work — namespace swaps, event renames, API translations — while leaving architectural decisions to experienced developers. Using a real WPF-to-Uno Platform migration of Text-Grab (84 C# files), the author demonstrates a structured approach: a migration contract file (CLAUDE.md) that encodes architectural decisions once and applies them consistently across all files, combined with MCP server-based verification loops that catch runtime bugs inside the agent's workflow. The result was a 60% reduction in code lines, elimination of heavy native dependencies, addition of 14 service interfaces and 1,208 unit test lines, and cross-platform reach expanded from Windows-only to Windows, WebAssembly, and macOS/Linux — with 26 of 30 features at full parity.
Table of contents
The Old Economics Were BrutalThe 80/20 Split Is RealThe Migration ContractThe Verification LoopThis Isn't "AI Replacing Developers"The New EconomicsTry It YourselfSort: