Buildsworn: Claude that proves your build works
Epic's official MCP lets Claude edit your Unreal project. Buildsworn makes sure Claude does not lie about it: compile gates, log gates, automation tests, screenshot verification, packaging and release, plus an index of your engine's API so it stops inventing signatures. Built on six shipped games.
The key and the installer arrive by e-mail within a minute. No card, no trial clock, no strings.
For companies and teams. Perpetual license, 12 months of updates included, then $149 a year for the whole team. Invoice on request.
Solo is free for individual developers: same tool, same updates, no feature cut. Studio is the license for a company or a team of up to five machines. Windows 10/11, UE 5.6 to 5.8, Claude Code required.
Studio is a digital product delivered immediately: no refunds once the key is issued, support included instead. Try the free Solo key first. By using Buildsworn you accept the EULA and terms.
Buildsworn Solo is free because people who find it useful chip in. Support the project with any amount, or just say hi on Discord.
Lost your key?
The problem it solves
A clean compile is not "it works". A process that stays alive for 8 seconds is not "it works".
Without Buildsworn
- Claude edits C++ and says "done". Nobody compiled.
- Sprites end up upside down, text outside frames, a black screen. The agent never looked.
- A 3000-line build log is pasted into context. Tokens burn, the fix is wrong.
- Every session starts from zero and rediscovers last week's bug.
With Buildsworn
/gatereturns a PASS/FAIL table: compile, function audit, tests, log scan, screenshot. "Done" is only allowed while quoting it.- Hooks make a backup before every edit, block sed on C++, and ask you before any kill, restart or delete.
- Compile errors come back as
file:line. A bounded agent loops compile-fix-compile until green. - Session state lives on disk. The next session starts with a briefing, not history.
What you get
One installer, three parts. Nothing to configure by hand.
MCP server, 162 tools
An API index built from your engine headers (about 300,000 classes, functions, properties, includes and deprecations), so Claude verifies every signature instead of guessing. Code navigation and safe edits, UnrealBuildTool compile (never Live Coding), packaging, plugin validation, quality gates
(gate_run, log_gate, ue_test_run, perf_gate), screenshots and game_visual_check,
session state, project notes, release pipeline. Optional PixelLab, Gemini review and your own SSH server.
Claude Code plugin
6 hooks (backup, no sed on C++, no base64 transfers, ask before kill/delete, compile digest, session brief),
skills /gate /compile /session-start /session-end,
agents: compiler fixer, adversarial QA, Blueprint reader, notes librarian, patch notes writer.
Playbook and lessons
The rules that keep an agent honest on a real game project, and a lessons database seeded with the traps we hit shipping six games (UE5 co-op horror, simulators, 2D arcade, a browser MMO). Your project starts with them and grows its own.
How a session looks
Real output of /gate on the demo project that ships with Buildsworn: one function declared without a body, caught before anyone says "done".
From the guides that ship with the product: Quickstart (zero to first map and first gate) and the Cookbook (eleven recipes from our own games: actors, multiplayer pickups, HUD, data tables, tests, crashes, Steam)
/session-start MyGame. Claude gets a briefing: done, next, known bugs, matching lessons.
Ask for the feature. Every edited file gets a .bak. sed on C++ is refused. taskkill asks you first.
/compile. UnrealBuildTool, right engine picked from the .uproject, errors as file:line, optional fix loop (max 5 rounds, stops on repeats).
/gate. Deterministic table. No log = FAIL. No screenshot = SKIPPED, never PASS.
/session-end. State to disk, decision and lesson recorded. Tomorrow starts running.
Requirements
| OS | Windows 10/11 x64 |
|---|---|
| Engine | Unreal Engine 5.6, 5.7 or 5.8 (launcher or source build) and Visual Studio 2022 with the C++ game development workload |
| Agent | Claude Code, installed and logged in (claude --version works). Any Claude plan that runs Claude Code. |
| Optional | PixelLab key (pixel art tools), Gemini key (second-opinion review), an SSH server of your own, Python Editor Script Plugin for in-editor tools on 5.6/5.7 |
| Install | One setup.exe with a 4-page wizard. It registers the MCP server and the plugin in Claude Code for you and builds the API index of your engine in the background (3 minutes). No Python needed. |
Questions
Is this a replacement for Epic's unreal-mcp?
No. Epic's server edits the editor (Blueprints, UMG, Niagara). Buildsworn owns the production side: building, gating, packaging, releasing, and keeping the agent honest. On UE 5.8 we recommend using both; Buildsworn also carries an editor bridge for 5.6 and 5.7.
How does the license work?
One key per person or purchase: Solo (free) covers two machines of one developer, Studio covers five machines of a company or team. The installer activates the key online once; a signed token keeps working offline for 30 days and renews itself. Changed PCs? Support resets your seats. The key never expires.
Why is Solo free? What is the catch?
No catch. Solo is the full tool with every update, for individual developers. Buildsworn grows faster with a thousand people gating their builds than with ten licenses sold, and companies pay for Studio because they need a license on paper, five machines and someone to answer the phone. If Solo saves you time, chip in what you like; it is optional and always will be.
What can the agent do on my computer?
Everything a developer can: run commands, kill processes, edit files under your profile and projects, take screenshots. The hooks make the dangerous actions ask first and back up first; Claude Code's permission prompt has the final say. The guide has a dedicated section on this.
Does it work with 2D games or non-Unreal C++?
The code tools, gates on logs and screenshots, session state and release tools are engine-agnostic. The compile and packaging tools are Unreal-specific.
Updates and support?
Solo gets every update, forever (buildsworn --update or the update_check tool). Studio includes 12 months of updates; after that the version you have keeps working forever and new versions need a renewal: $149 a year for the whole team, bought here with the same PayPal e-mail, no reinstall. Support through the contact form or Discord, reply within two working days.
Renew Studio with the same PayPal e-mail you bought with; the confirmation arrives by e-mail, nothing to reinstall.
Support the project
Solo is free and stays free. If Buildsworn saved you a night of debugging, pay what you want.
Every dollar goes into the next release. You get a thank-you e-mail, nothing else changes: Solo is not a trial and support unlocks nothing. Prefer to help with words? Report bugs and ideas on Discord.