A coding agent that runs on an iPhone 3G.
Not a remote control for one somewhere else — the model streams to the phone, the tool calls run on the phone, and the compiler is on the phone. You describe an app; GCC 4.2 on a 2008 ARM11 builds it and it appears on the home screen. The whole loop fits in 128 MB of RAM, because it has to.
Built for iOS 4.0 on the iPhone 3G (armv6) and iPhone 3GS (armv7)
with a current Xcode toolchain, which is a thing the current Xcode toolchain
refuses to do in three separate ways. blog/ has the long version.
Bring your own key. Three settings — base URL, API key, model — and
requests go straight from the phone to that endpoint. No server of ours, no
account, no device identity. The wire format is OpenAI's /chat/completions,
so the same field points at Anthropic's compatible endpoint (the default),
OpenRouter, or a llama.cpp server on your own Wi-Fi.
To install it: give INSTALL.md and this repository to a
coding agent. That is the release. There are no prebuilt packages — an iOS 4
phone's OpenSSL speaks TLS 1.0 and cannot fetch one from anywhere on today's
web.
Jailbroken devices only. Substrate is a runtime dependency; every phone Legacy-iOS-Kit jailbreaks has it.
make # build/AirBuild3G.app (armv6 + armv7, plus the setuid helper)
make verify # architectures and the load commands iOS 4's dyld demands
make test # JSON parser, reply splitting, project store, stash, tools
make package # all three .deb packages
make install-device DEVICE=root@<ip>Needs the iOS 4.1 SDK (~/theos/sdks/iPhoneOS4.1.sdk, or LEGACY_SDK=) and
brew install dpkg ldid. Without ldid the binary is unsigned and will not
launch.
Xcode 27 ships only the iOS 27 SDK, and its linker blocks a 4.0 target three
ways. The compiler is fine — Clang still emits armv6 and still accepts
-mios-version-min=4.0.
| Blocker | Workaround |
|---|---|
The iOS 4.1 SDK's dylibs predate LC_VERSION_MIN_IPHONEOS, so ld sees platform unknown and errors |
tools/mkstubs.py regenerates them as .tbd stubs declaring armv7-ios |
ld: building for iOS with 4.0 minimum deployment target is no longer supported |
Link at 5.0, then tools/patch_minos.py stamps the load command back to 4.0 |
ld: linking for armv6 is no longer supported |
Compile real armv6, relabel cpusubtype to armv7 for the link, relabel back (tools/relabel_arch.py) |
Headers still come from the real SDK via -isysroot; only the link is
redirected. make verify then checks the three things that produce a binary
which builds cleanly and cannot be loaded: LC_VERSION_MIN_IPHONEOS 4.0,
LC_UNIXTHREAD rather than LC_MAIN, and the Thumb bit on every method IMP
in the armv7 slice.
AGENTS.md is the working agreement: every non-obvious constraint, and why.
Read it before changing anything in tools/ or LDFLAGS.
The open-source relative of the AirBuild client at air.build, with the account, the metering and the device binding taken out and your own API key in their place.
MIT. Third-party packages it installs on the phone are not ours —
Packaging/payload.lock names every one by URL and sha256, and this
repository redistributes none of them.