nomad — Fe2O3 on the phone

How it works

Each app carries one Fe₂O₃ workflow off the laptop and onto an Android phone. The interesting code lives in Rust and is shared with the desktop tools, so the phone and the terminal compute identically — the Kotlin side stays a thin shell.

Shared Rust core

One crate (fe2o3-mobile-core) holds the models, parsers, transforms and engines — the same logic as the desktop tools. Exposed to Kotlin through UniFFI, which generates the bindings. Never hand-rolled JNI.

Thin Compose shells

Compose for screens, Glance for home-screen widgets, WorkManager for background work that respects Doze and App Standby. No business logic that could live in the core.

Syncthing, not cloud

Data rides the same Syncthing channel the desktop already uses — todo.hl, gear.json, the relay gateway, .xrpn programs. One source of truth, no account, no middleman.

One monorepo

A single Cargo workspace and Gradle multi-project. Each app ships as its own signed APK with its own launcher icon, sideloaded from the synced folder. minSdk 33, Material 3.

The apps

Seven phone apps, each pairing with a tool from the Fe₂O₃ family.

tasks

HyperList todo

Pairs with scribe & kastrup

Editor + Glance home-screen widget for the same ~/.tasks/todo.hl hyperlist that scribe edits and kastrup's z triage appends to.

apps/tasks

hyperlist

HyperList editor

Pairs with scribe

A general HyperList editor: full syntax highlighting, fold, drag-reorder across depth (collapsed items move as one), and auto-renumber.

apps/hyperlist

relay

Notification gateway

Pairs with kastrup

Relays WhatsApp / Messenger / Instagram / SMS / Discord (and photo previews) into kastrup and fires replies — replacing the laptop's Firefox/Marionette bridge with an on-device listener.

apps/relay

astro

Astronomy companion

Pairs with astro

Ephemeris, met.no weather + observing conditions, in-the-sky events, APOD, starchart, and a telescope/eyepiece gear catalog — the gear.json shared with desktop astro.

apps/astro

watchit

Movie / series browser

Pairs with watchit

TMDB browser — top-rated & popular lists, your own wish and dump lists, posters, full detail (cast, plot, streaming), and search-to-add.

apps/watchit

amardice

RPG dice roller

Pairs with amar

Amar RPG O6 roller: D6, skill, and combat rolls with the full crit/fumble tables, plus fear rolls with mental-fortitude vs a fear DR. Engine shared with the desktop and the d6gaming wiki.

apps/amardice

xrpn

RPN calculator

Pairs with xrpn

Pocket HP-41 RPN scientific calculator — full stack, registers, modes and the XRPN command set, an HP-41-style multi-shift keypad, persistent state, and a FOCAL program runner that loads .xrpn files from the synced folder.

apps/xrpn

Build & sideload

Clone the monorepo, build the app you want, drop the signed APK in a Syncthing-shared folder, and sideload it on the phone:

# host tests for the shared Rust core (no emulator needed)
PATH="/usr/bin:$PATH" cargo test -p fe2o3-mobile-core

# a signed release APK (cargo-ndk + uniffi-bindgen run from Gradle)
export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
export ANDROID_NDK_HOME="$HOME/.android-sdk/ndk/27.2.12479018"
./gradlew :apps:xrpn:assembleRelease

# APK lands in apps/<name>/build/outputs/apk/release/ — sync & sideload