Decompilation
Rock Band 3 (Xbox 360) — 18,689 functions matched
Byte-exact decompilation of a symbol-less Xbox 360 binary: 18,689 functions matched in eight weeks by orchestrating fleets of Claude Code agents.
Xbox 360 · agent orchestration · reverse engineering
Progress
Matched code (fuzzy, game + engine target scope)
62.7%
as of July 19, 2026
- May 26, 2026: AI decomp effort begins — First fork commits scaffold the engine and build pipeline from the sibling Dance Central 3 decompilation.
- Jun 11, 2026: 978 names from Wii sibling — Cross-compiler symbol identification ships 978 vetted function identities from the Wii decompilation.
- Jun 21, 2026: Cheap veins declared exhausted — Wave-20 close-out declares the cheap-matching format exhausted and pivots strategy.
- Jul 8, 2026: Retarget to Title Update 5 — Mid-flight switch to the final updated executable, peaking at 190 commits in a day.
- Jul 17, 2026: +1,871 names in a mega-run — Identification stack (fingerprints, Ghidra, BinDiff) names 1,871 functions in one push.
- Jul 19, 2026: COMDAT-scatter fix: +1,176 in a day — Diagnosing linker-scattered code attribution yields 1,176 new byte-exact matches in a single day.
- May 26, 2026: 34 commits — Effort begins: engine scaffolded from DC3 sibling
- Jul 10, 2026: 190 commits — Busiest day: 190 commits
- Jul 19, 2026: 110 commits — COMDAT-scatter day
Source: self-measured with objdiff-cli 4.2.3 (decomp-synth progress-history job 6d53): per-commit fork measurements, dtk-era pinned; 0% anchored on the eve of the fork's first commit (2026-05-26) — day one imported the sibling engine scaffold, giving immediate partial credit
A matching decompilation of Rock Band 3 for the Xbox 360, held to the strictest standard the console-preservation community recognizes: clean-room C++ that, when compiled with the original Microsoft toolchain at retail optimization flags, produces machine code byte-identical to the shipped executable. The twist is scale and method — over roughly eight weeks, a single person orchestrating fleets of Claude Code agents byte-matched 18,689 functions of a retail binary that shipped with zero debug symbols, across 1,472 commits.
With no symbols, every function starts as an anonymous address. The project bootstraps identification by treating two sibling decompilations as Rosetta Stones: a Dance Central 3 decomp (same engine, same compiler, symbols available) serves as the engine and toolchain oracle, while a Wii decomp of the same game serves as the game-code oracle. Fingerprint matching over strings, callees, and constants — plus structural diffing through Ghidra and BinDiff with a custom SLEIGH fork for the Xenon vector ISA — triangulates names into the stripped binary.
The infrastructure is as much the story as the matches. Dozens of concurrent agents work through an eleven-tool MCP orchestrator backed by SQLite, isolated in a copy-on-write reflink worktree pool so no agent can corrupt another’s build. A content-addressed compiler cache cut cold rebuilds from about five minutes to 3.5 seconds. Evidence-graded state documents let an AI coordinator classify dead ends honestly and escalate genuine resourcing decisions back to the human.
The hardest problem was a large pool of correctly named functions stuck at 0% match. The diagnosis: the linker scatters per-function COMDAT sections freely across the binary, so functions were being attributed to the wrong translation units — the source was right; the linker’s layout was lying. Diagnosing this and applying three byte-neutral fix shapes produced +1,176 strict matches in a single day.
Current state, measured against the whole executable with no denominator gaming: 73.1% of game code and 60.4% of the shared engine matched. The project is active, sitting at a deliberate strategic pivot — the cheap veins are exhausted, and the remaining long tail is being routed to automated grind machinery while several techniques (COMDAT-scatter fixes, empirically gated precompiled headers, object-symbol-table patchers) ship back to the wider decompilation community through shared tool forks.