Paul HittandClaude Opus 5
b74cc1907f
Android's Session.sendCallSignal called the send path and threw the result away. That result is the same Sent every other send returns - how many devices took it, which failed - so an offer that reached NOBODY was indistinguishable from one that rang. The caller watched "Calling..." for a signal that had gone nowhere, and neither device had anything to say so. The same shape as the message-loss bug fixed earlier today, on the one path where the UI never shows a delivery banner because a call is placed from inside a WebRTC callback. Also instruments the drops. An incoming offer can be discarded in five places in iOS's CallManager - already-ended, older than the dial timeout, busy, wrong state, unknown id - and every one was a bare `return`. Working out which of the five happened costs more than the logging does. Same treatment E2EInbox.dropped already gives ingest, and for the same reason. Not a fix for "Android calls iOS and nothing happens" - I have not reproduced that. It rules out and instruments: the wire shapes match, iOS builds its CallManager eagerly at sign-in so onCallSignal is always hooked, Android sets no from_addr so the federated fork is not swallowing it, and every clock (mac, host, relay, db) agrees within a second so the staleness check is not misfiring. The next attempt will say where it stopped instead of nothing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Flamenet Messenger — Android
Nothing here is an app yet. This is the engine, and it is deliberately first.
An Android client needs the protocol implemented a third time. That third
implementation is the one that finds the places where the specification says
less than the two existing engines quietly agreed on — but only if it is
written against the spec and the published vectors rather than against a
reading of our own Swift and JavaScript. So the engine comes first, it is a
plain Kotlin/JVM library with no Android in it at all, and it is held to
engine/test/vectors/protocol-v1.json — the same file the other two engines
are checked against, read from that one location rather than copied here.
./gradlew :engine:test
No Android SDK, no emulator, no device. It runs anywhere a JVM does, which is also what lets it run in CI on Linux.
What the engine covers today
| Area | Spec | State |
|---|---|---|
| Safety numbers | §7 | Done — fingerprints and conversation ordering match the published vectors |
| Key transparency verification | §19 | Done — RFC 6962 leaf/node hashing, unbalanced split, bottom-up audit paths |
| Byte helpers | — | Unsigned comparison, constant-time equality |
What it does not cover
Listed rather than left to be discovered, because a table of green ticks with the hard parts quietly missing is worse than no table:
| Area | Spec | State |
|---|---|---|
| X25519 / Ed25519 | §3 | Not started — needs a provider that works on both JVM and Android |
| X3DH key agreement | §4 | Not started |
| Double Ratchet | §6 | Not started |
| Sealed sender | §12 | Not started |
| ML-KEM-768 hybrid | §11 | Not started |
| ML-DSA-65 identities | §20 | Not started |
| Relay client | §8 | Not started |
| The app itself | — | Not started |
Until those exist, Android is honestly marked "not started" on the website, and a conversation gets the protocol's guarantees only when both ends are iOS.
Why the vectors matter more than the code
Two implementations that agree may both be wrong in the same way, especially when one was written while reading the other. The audit-path ordering in §19 is the worked example: a top-down reading of a bottom-up path produces the correct root for every left-spine index, so it passes any test that only checks index 0. The vector file pins a right-descending index for that reason, and the Kotlin tests assert both that the published path verifies and that the same path reversed does not.
If this engine ever disagrees with the file, the interesting question is which of the three is wrong — not this one by default.