# Stop Letting Claude Code Hallucinate Your Modernization: Write OpenRewrite LST Recipes Instead

> Source: <https://dev.to/machinecodingmaster/stop-letting-claude-code-hallucinate-your-modernization-write-openrewrite-lst-recipes-instead-il6>
> Published: 2026-08-10 04:15:12+00:00

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Stop Letting Claude Code Hallucinate Your Modernization: Write OpenRewrite LST Recipes Instead

Letting autonomous AI agents directly rewrite million-line Java monoliths is a dangerous game of Russian roulette with silent runtime bugs. The real way to execute large-scale JDK 26 upgrades is using Claude Code CLI to author deterministic OpenRewrite LST recipes—not blindly edit source files.

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Why Most Developers Get This Wrong

- Yolo-prompting Claude Code CLI to edit hundreds of
`.java`

files directly, introducing non-existent API calls and broken imports.
- Treating OpenRewrite Lossless Semantic Trees (LST) like naive regex text manipulation instead of type-attributed AST structures.
- Relying on LLM self-correction loops to fix hallucinated method signatures instead of relying on the Java compiler.

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The Right Way

Use Claude Code CLI to generate, unit-test, and refine type-safe OpenRewrite Java recipes, then let `rewrite-maven-plugin`

execute them deterministically.

- Prompt Claude Code to extend
`org.openrewrite.java.JavaVisitor`

targeting specific legacy patterns (e.g., Spring Boot 3+ or Jakarta EE migrations).
- Validate recipe execution against OpenRewrite's type-attribution engine to guarantee zero semantic drift across your codebase.
- Execute the generated recipe via
`mvn rewrite:run`

in a clean CI container for 100% reproducible diffs.
- Isolate LLM non-determinism to the recipe authoring phase—keep your production target repo completely deterministic.

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Show Me The Code (or Example)

Prompt Claude Code CLI to generate this exact imperatively-safe recipe structure:

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Key Takeaways

- LLMs generate logic; deterministic AST engines transform code—never confuse the two responsibilities.
- Generating OpenRewrite recipes via Claude Code gives you compiler-backed type safety across enterprise-scale Java migrations.
- If an AI-driven refactor isn't backed by a Lossless Semantic Tree parser, it belongs nowhere near your production monolith.