Melee Decomp Assistant

A desktop GUI tool for contributing to the doldecomp/melee decompilation of Super Smash Bros. Melee. Covers the full workflow — from installing dependencies and cloning the repo, to diffing assembly, generating decomp.me context, and submitting matched functions.

No API key required.

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Features

One-time setup wizard

Walks through every prerequisite in order: devkitPPC, Git, cloning the melee repo, Dolphin disc extraction, and the initial ninja build. Each step has a button that does the work — no terminal required.

Function browser

Searchable, filterable table of every function in the project showing name, module, address, line count, and current match percentage from report.json. Green = matched, orange = in progress, white = not started.

Analyze window

Before committing to a function:

• Assembly viewer scoped to just that function (toggle to see the full unit file)
• Live decomp.me scratch lookup showing the best public match and author
• One-click access to the decomp.me helper, assembly copy, and the loop

Decompilation loop

Split view: editable C source on the left, live objdiff output on the right.

• Check — compiles the function in isolation, diffs against target, no repo changes
• Build & Check — full ninja build, writes to repo, commits if it compiles
• Attempt history with click-to-restore
• Restore Original resets to the decompiled starting point

AI workflow (bring your own chat)

Works with any AI — Claude, ChatGPT, Gemini, etc. No API key needed.

• Copy Prompt — assembles a complete prompt with target assembly, current C, diff, sibling functions for struct context, and attempt history
• Feed Reply — reads NEED_TYPE: / NEED_SYMBOL: requests from clipboard, resolves them from project headers and symbols.txt, and copies a follow-up ready to paste back

decomp.me helper

Prepares all four decomp.me fields in one window:

Field	What's generated
Diff label	Function name
Target assembly	.fn/.endfn block, macros expanded, @sda21 substituted
Context	Headers inlined recursively; missing types resolved from project headers; _struct_* stubs generated; global externs inferred
Source code	Target function only, no #include lines

Submission guide

Step-by-step walkthrough of the full submission process: match verification, deleting the .s stub, staging, git clang-format, committing, and opening a PR or GitHub Issue.

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Requirements

• Python 3.10 or later
• The doldecomp/melee repo built with ninja (the setup guide handles this)
• A NTSC-U v1.02 Melee disc image (Game ID: GALE01) for the initial build

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Installation

Windows (recommended)

Download run.bat from the latest release and double-click it. It installs Python if needed, then installs all dependencies automatically.

From source

git clone https://github.com/Bootstrings/melee-assist.git
cd melee-assist
python run.py

run.py installs dependencies on first launch and keeps them up to date on subsequent runs.

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First launch

The setup guide opens automatically if no melee repo is configured. Follow the steps in order:

1. Get a disc image — NTSC-U v1.02 only (GALE01)
2. Clone the repo — click Clone... or run git clone https://github.com/doldecomp/melee.git
3. Extract game data — use Dolphin → right-click ISO → Properties → Filesystem → Extract System Data into orig/GALE01/ inside the cloned repo
4. Configure and build — click Run next to python configure.py, then Run next to ninja
5. Point the app at the repo — Settings → General → Melee Repo Path

Once the build completes the function list loads automatically.

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Usage

Finding a function to work on

1. Browse the function list — filter by module or match status
2. Click Analyze to inspect the assembly and check for existing decomp.me scratches
3. Click Open Loop → (or double-click in the main list) to start working

The decompilation loop

1. Edit the C source in the left panel
2. Click Check to see the diff — fast, nothing written to disk
3. Refine until the match percentage climbs
4. When satisfied, click Build & Check for a full repo build

Working with an AI

1. Click Copy Prompt and paste into any AI chat
2. If the AI responds with NEED_TYPE: or NEED_SYMBOL: requests, click Feed Reply — it resolves them automatically and copies the follow-up
3. Paste the AI's C into the editor and click Check

Submitting a matched function

Click How to Submit in the loop window for the full step-by-step guide.

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Project structure

run.bat / run.py          # launcher and bootstrap
src/melee_assist/
  ui/                     # all windows (app, loop, analyze, settings, ...)
  loop/                   # decompilation loop and context packaging
  build/                  # ninja runner and objdiff integration
  setup/                  # dependency checker and installer
  api/                    # decomp.me API client
  assembly/               # report.json parser
  resolver/               # symbols.txt and header type lookup
  llm/                    # prompt templates
uninstall.bat             # removes installed dependencies (respects pre-existing tools)

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Notes

• The app only installs tools it needs and tracks which were already present before first launch — uninstalling will not remove tools you had before
• The bundled objdiff-cli from the melee repo is always preferred over any system version, since the repo pins a specific version for consistent match percentages
• decomp.me scratch search is approximate and searches public scratches by function name — it may miss private or differently-named scratches

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License

MIT — see LICENSE