root cause (proven, not inferred): contentDetails.boundStreamId on
liveBroadcasts.insert does NOT bind the broadcast. Our diagnostic reads
lifeCycle=created privacy=private autoStart=true bound=NONE
boundMatches=NO-BINDING | streamStatus=active
created is Google's "incomplete settings" state, so enableAutoStart has no
bound stream to fire from; close-out then 403s invalidTransition because
created -> complete is not a legal edge. A reusable stream accepts bytes for
a broadcast that isn't watching it, so a perfectly healthy 99MB RTMP session
is exactly what an unbound broadcast looks like -- every observable pointed
away from the binding.
Google's migration guide states the rule outright: a liveBroadcast must be
bound to exactly one stream before it can start, and is not bound at creation.
That was in the docs read during the original design and was not applied.
Shipped:
- BindBroadcastAsync -> POST liveBroadcasts/bind?part=id&id&streamId (no body),
called from PrepareAndStartLiveAsync right after CreateBroadcast, before the pump.
Failure is fatal to the session: an unbound broadcast can never go live, so a
live-looking UI over one is a lie.
- boundStreamId removed from the insert body, and the streamId parameter removed
from CreateBroadcast. A parameter that looks meaningful but cannot affect the
outcome is what made the misdiagnosis possible.
- Replaced CreateBroadcast_With_StreamId_Binds_Reusable_Stream_At_Insert, which
asserted the disproven behaviour and therefore laundered a guess into a
guarantee, with tests for the omitted field and the real bind endpoint.
Error messages (creator ruling 2026-10-04): bind failures are not all "check the
sign-in". Six documented reasons exist and only one is auth; BindFailureMessage
gives each its own text, and the fallback passes the raw reason through verbatim
so an unmapped reason stays greppable. liveBroadcastBindingNotAllowed matters
most -- it means our ordering is wrong, and a generic re-auth message would hide
a bug in our own code behind a plausible excuse. See MyMistakes.md.
ai.md: also corrects the TASK 44 claim that liveChatId is only populated once the
broadcast is live. The diagnostic shows it present while lifecycle is created.
That claim was inferred from a sample's active-status guard, which is not a spec.
Suite 395/395, 0 warnings.
The open creator report ('I still cannot post a chat message in the TEST tab',
feedback 'Chat polling couldn't start — Mock Chat Input is disabled') was a single
cause: the liveChatId never resolved. Two YouTube API facts:
1. The id lives in snippet.liveChatId — contentDetails has no such property
(TASK 44 read part=contentDetails: could never resolve).
https://developers.google.com/youtube/v3/live/docs/liveBroadcasts
2. It only exists once the broadcast is LIVE — the official sample lists
broadcastStatus=active, and our fetch ran before the frame pump pushed RTMP
(enableAutoStart flips ready→live). A ready-state list legitimately returns
no id.
https://github.com/youtube/api-samples/blob/master/java/src/main/java/com/google/api/services/samples/youtube/cmdline/live/GetLiveChatId.java
Fix: GetBroadcastLiveChatIdAsync reads part=snippet and polls with a bounded
retry (10x/2s); PrepareAndStartLiveAsync starts the frame pump FIRST, then
resolves the id. Chat stays non-fatal. Docs ai.md/TASKS.md/HANDOFF.md +
MyMistakes recipe updated same commit. TASK 44.
Good Dog: ONE integration test (GetBroadcastLiveChatIdAsync_Polls_Snippet_...
) drives a broadcast that gains its id mid-retry and asserts every request used
part=snippet. Gate: clean build 0 warnings, vstest 318/318.
startup.log 2026-09-22 (user runs of the new build): ALL THREE session stops
logged 'Broadcast transition(complete) failed (403) invalidTransition → End
close-out: enableAutoStop will finish'. The old ai.md assumption ('invalidTransition
when autoStop already fired') was wrong — the blind complete POST races
YouTube/autoStop marking the broadcast complete (enableAutoStop=true is always
set, tests included), so a blind POST earned only the 403 + log noise. Per the
transition errors table, invalidTransition is a current-status problem and
complete is not gated on streamStatus (only testing/live are):
https://developers.google.com/youtube/v3/live/docs/liveBroadcasts/transition
Fix: EndBroadcastAsync pre-flights liveBroadcasts.list -> status.lifeCycleStatus
and skips the POST when the broadcast is already complete/revoked; an inconclusive
pre-check still posts (old behavior) rather than silently stranding a live
broadcast; still never throws (enableAutoStop finishes every skip).
Good Dog: EndBroadcast test rewritten to the one contract — live -> GET pre-check
+ POST transition (URL shape asserted); already complete -> zero transition POSTs;
inconclusive pre-check + 403 POST -> error string, never a throw. Full suite
315/315 (one-run audio/mouse timing flakes cleared), build 0 warnings.
Recipe recorded in MyMistakes.md; ai.md / Services index / TASK-9 note corrected.
startup.log 2026-09-22 (via the user's run of the new build): every session
start logged 'Stream health poll failed: The requested operation requires an
element of type String, but the target element has type Object'.
Root cause: GetStreamHealthAsync did status.healthStatus.GetString(), but the
real API nests it as status.healthStatus = {status, lastUpdateTimeSeconds,
configurationIssues[]} — an OBJECT, per the liveStreams reference
https://developers.google.com/youtube/v3/live/docs/liveStreams (checked the
docs before fixing, per derivative-work rule). Our flat-string fixture was the
wrong assumption since TASK 9; the report-by-exception health banner had been
silently dead.
Fix: read the nested healthStatus.status + nested configurationIssues[], tolerating
the legacy flat-string shape so nothing else breaks. Tests flipped to the real
object shape (the Good Dog for this change). Full suite 315/315, build 0 warnings.
Also recorded in MyMistakes.md (API-shape recipe) and ai.md/Services index. End-of-session
transition(complete) 403 invalidTransition (enableAutoStop fallback) observed on all three
2026-09-22 stops — separate racy-design issue, carried, not in this change.
The specced 'End stream -> transition(complete)' call never existed: stopping relied
entirely on enableAutoStop (viewers sat on a frozen stream-offline for ~a minute, VOD
finalized late). Found during the 2026-09-01 recording-verification pass while the
creator asked 'if there's proper close-out info yt needs, we'll provide it?'
EndBroadcastAsync POSTs liveBroadcasts/transition?broadcastStatus=complete&id=..&part=status,
called after the pump stops (RTMP EOF first) and only when a live session had a broadcast —
record-only stops stay offline. invalidTransition/410 (autoStop already ended it) is logged
and returned as an error string, never thrown: a stop must never fail over close-out.
ONE integration test (URL shape + never-throws on 403). ai.md/TASKS.md design lines marked
SHIPPED with the map-lie note.
Ref: https://developers.google.com/youtube/v3/live/docs/liveBroadcasts/transition
gramps