Root causes, each reproduced against the live server or endpoint:
- Server-only JIDs decoded as "@s.whatsapp.net" and pairing replies copied them
into `to`, so the device was never registered and every login returned 401.
Decoder/encoder fixed, replies use s.whatsapp.net, ADV hosted prefixes follow
whatsmeow. The link wizard now waits for the restart, logs in, uploads prekeys
and retries once with a fresh device on 401/403.
- Closed sockets made every receive loop spin until its deadline (the 7 minute
CPU burn). Loops stop on a closed stream.
- whatsapp_send had no image argument and send_image was a stub. Added WaMedia
(byte-exact against 8 wa-go golden vectors), media_conn upload, image send and
the DeviceSentMessage copy for the user's other devices.
- Phone contacts never reached the client: added app-state sync (WaAppState,
WaReceiver, LTHash and MAC checks verified against a whatsmeow-built oracle)
and the historySyncConfig declaration at registration.
- Contact lookup: FTS5 trigram plus fuzzy ranking, ambiguity is reported and
never guessed, global search lists contacts. Send caps (10/min, 200/day) are
enforced and survive unlink.
Failover and agent:
- Every failed backend candidate is printed the moment it fails.
- muse runs with low reasoning effort, an empty preset and one stable workspace
(36.5s down to 2.8s on the real prompt); Ctrl-C no longer counts as a backend
failure; CLI backends use the circuit breaker; opencode runs are capped at 30s.
- Orphan tool results are dropped before sending (devplace HTTP 400, reproduced);
compaction no longer starts its window on a tool result.
- Terminal art pasted as a prompt is refused before any model call.
Tests: whatsapp_test, muse_flags_test, llm_history_test; full suite 40 steps
(agent.e2e reads live tmux panes and is flaky, green on re-run).
Research archived under research/whatsapp-automation.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>