SERVICE 01

Codebase Modernization

Retire technical debt with agentic coding.

example.ts

// Large-scale refactor — plan first, then execute
const modernizer = new Subagent({
  model: "claude-opus-4-6",
  role: "legacy-refactor",
  tools: [repoSearch, astRewrite, runTests, openPR],
  mode: "plan",  // explore + propose before touching code
});

const plan = await modernizer.plan({
  task: "Port reservations-service from Java 8 to 21 + Spring 6",
  successCriteria: ["all tests green", "no public API changes"],
});

// Multi-pass review: per-file + cross-file integration
await modernizer.execute(plan, { review: "multi-pass" });
// → 142 files modernized · 37 PRs · 0 regressions

What it is

Legacy code isn't a documentation problem — it's a reasoning problem. The systems that are hardest to modernize are the ones where nobody left on the team remembers why they were built a certain way. Claude reads the code, reconstructs the intent, and proposes changes that preserve behavior.

We retire technical debt with agentic coding: mainframe-to-cloud migrations, monolith decomposition, framework version jumps, and language ports. We start every engagement in plan mode — Claude explores the codebase, maps dependencies, and proposes the migration order before touching a file. The heavy lifting then runs in Claude Code with custom subagents scoped to your repository, your conventions, and your test harness. Large reviews run as multi-pass: a focused per-file pass plus a cross-file integration pass, so nothing gets missed to attention dilution. Claude also lives in your CI/CD — reviewing PRs, generating tests, and catching regressions before humans touch them. Built on Anthropic's Code Modernization Starter Kit and extended for your stack.

What you get

01
Modernization assessment Scoped audit of the legacy surface — modules, failure modes, blast radius, and a prioritized migration order.
02
Custom subagents Claude Code subagents tuned to your repo conventions, coding style, and test infrastructure.
03
Automated refactors Large-scale code rewrites executed by Claude against a passing test suite, landed as reviewable PRs.
04
CI/CD code review Claude wired into your pipeline for automated PR review, test generation, and static-analysis follow-up.
05
Test generation Regression coverage for untested legacy paths, produced alongside the modernization work.
06
Handoff documentation Architecture deltas, decision log, and the runbook your team needs to keep the work going.

How we engage

A process designed for production.

Legacy audit

We map the codebase with Claude — inbound dependencies, risky modules, untested paths, and the order we'll take them in.

Subagent setup

We configure Claude Code with project-level CLAUDE.md, custom subagents, and the permissions and hooks your team is comfortable with.

Iterative refactor

Subagents run refactors against your test suite. Every change lands as a PR your engineers review — no silent rewrites.

CI wiring

Claude is wired into the pipeline so review, test generation, and regression catches continue after the engagement ends.

Tech stack

Claude Opus 4.6 Claude Sonnet 4.6 Claude Code Code Modernization Starter Kit TypeScript Python Java

Ready to build something that actually works?

We start every engagement with a two-week discovery sprint. No retainer required. You walk away with a spec whether you build with us or not.

Start a project →