Reliability for FAST channels and ad-supported linear,
on a programming-clock the agent owns.
The Streamwake reliability loop applied to the four failure modes free ad-supported linear inherits — manifest drift on long-running channels, encoder regressions on long-running channels, regional CDN brownouts during primetime ad breaks, and SCTE-35 mid-roll marker misalignment that lands the ad break at slate. Detected, classified, fixed, verified, and written up before the next programming-clock transition.
Four failure modes
FAST lanes inherit.
The same scheduled-programming traffic that makes FAST the highest-margin ad-supported business on streaming also concentrates failures at the primetime mid-roll ad break and on the long-running on-air cohort. Four of them show up only on FAST lanes — and each one has a known playbook the Streamwake agent owns.
Detect. Classify. Fix. Verify. Report.
The same four-act loop the Streamwake reliability agent runs on every cohort, tuned for the four pain points above — and the long-running, programming-clock traffic they all hit on a FAST lane.
Reroute the regional peer when the primetime mid-roll hits, retune the long-window encoder switchover on the FAST lane, snapshot + reissue the packager when the long-running channel drifts, split the cue-pass policy when the SCTE-35 marker lands at slate, and write up the postmortem in Slack and Linear before the next programming-clock transition.
How the loop runs on your FAST lane.
Each use case shows what the agent sees, how it ranks the hypotheses, what the fix branch looks like, how the recovery is verified, and where the write-up lands — followed by the postmortem that proves it ran in production on a FAST cohort.
What the agent does on a weekday FAST cohort when the long-running on-air packager drifts at the next programming-clock transition and the per-channel probe catches the median-hiding drift.
- DetectPer-channel parse-stall at 9% + EXT-X-MEDIA-SEQUENCE drift
The per-channel probe pattern reads EXT-X-MEDIA-SEQUENCE drift and parse-stalls on the long-running channel while the cohort median stays green — a 9% parse-stall on a single on-air lane is the smoking gun.
- Classifymanifest_packager_segment_drift_long_channel at 88%
Top hypothesis: manifest_packager_segment_drift_long_channel; the per_title_packaging_regression and discontinuity_injection_stitcher lanes are ruled out from the per-channel probe result.
- FixSnapshot + reissue the packager for the affected channel only
Snapshot the clean source window for the affected on-air channel, reissue the manifest from the snapshot, and split the packager so the rest of the FAST lanes hold the anchor while the affected channel recovers.
- VerifyPer-channel parse-stall returns under 0.5%
A re-read of the per-channel probe pattern confirms the parse-stall rate has dropped back under 0.5%; the cohort on the other FAST lanes is unaffected.
- ReportPostmortem in Slack + Linear
Structured write-up with the per-channel probe packet, the EXT-X-MEDIA-SEQUENCE drift, and the agentic-act split lands in the channel with the affected on-air channel flagged as the scope of the fix.
What the agent does on an 8-hour FAST lane when the cohort median hides the long-window encoder drift until the primetime slot opens and the buffer-cliff spike gets misattributed to player-side switching.
- DetectMid-window CWA overshoot + egress flag on the primetime lane
The encoder mid-window CWA overshoots the cohort-aligned target on the 8-hour FAST lane; the egress-budget lane flags the overshoot at the primetime slot open even though the cohort median is still green.
- Classifyencoder_abr_ladder_drift_long_window at 87%
Top hypothesis: encoder_abr_ladder_drift_long_window; the encoder_abr_switchover_overshoot and manifest_packager_segment_drift lanes are ruled out from the multi-window probe result.
- FixRetune long-window switchover + raise egress tolerance
Retune the encoder mid-window switchover against the long-window cohort baseline, raise the egress-budget tolerance on the affected encoder pool, and pin the rendition profile to the recovery bucket for the FAST lane.
- VerifyMid-window CWA snaps to cohort target
A re-read of the affected mid-window confirms the weighted average has snapped to the incoming rung; buffer-cliff frequency on the panel-set devices returns to baseline.
- ReportPostmortem in Slack + Linear
Structured write-up with the long-window drift chart, the egress-budget tolerance, and the agentic-act split lands in the channel with the affected FAST lane flagged.
What runs against the pre-mid-roll egress lane when a regional peer absorbs the primetime ad-break traffic spike and the buffer-cliff on the affected cohort gets misattributed to the player instead of the CDN.
- DetectCDN-side egress spike + cue-coverage gap on the pre-mid-roll peak
A buffer-cliff lands on the regional cohort at the mid-roll ad break — but the cohort QoE at the top of the show is unaffected. Probe pattern joins CDN egress to cue coverage and reads the egress spike preceding the cliff on the regional peer.
- Classifyregional_cdn_brownout_ad_break at 89%
Top hypothesis: regional_cdn_brownout_ad_break; the player-side switchover and license_server_cold_start lanes are ruled out from the regional egress envelope.
- FixRegroup regional egress + pin cohort to the warm peer
Regroup regional egress to a warm peer for the affected cohort, raise the egress budget tolerance on the affected regional POP, and pin the cohort until the affinity heuristic confirms parity.
- VerifyBuffer-cliff frequency returns to baseline
A cohort-aligned QoE probe on the affected regional cohort confirms the buffer-cliff frequency has snapped back to baseline; the egress-budget lane is back inside target before the next mid-roll.
- ReportPostmortem in Slack + Linear
Structured write-up with the regional egress envelope, the warm-peer regroup, and the agentic-act split lands in the channel with the affected regional cohort and the pre-mid-roll peak flagged.
What the agent does at the primetime mid-roll on a weekday FAST lane when the SCTE-35 cue alignment drifts out of window and the mid-roll ad break lands at slate or black-frame — a direct miss against the ad-server SLA.
- DetectMid-roll cue misalignment + slate duration spike
The probe pattern reads cue-pass timestamps on the FAST lane at the same window and sees the `splice_insert` marker land before the program-return anchor; the slate duration on the affected cohort spikes past the cue budget.
- Classifyscte35_marker_misalignment at 90%
Top hypothesis: scte35_marker_misalignment; the stitcher_cue_filter_overshoot and packager_preflight_drift lanes are ruled out from the parallel probe result.
- FixSplit cue-pass policy + reissue mid-roll alignment
Split the encoder/packager cue-pass policy to recover the splice seam, reissue the mid-roll alignment against the clean program-return anchor, and raise the cue-coverage probe threshold so the misalignment triggers on the next sync window.
- VerifyMid-roll cue coverage recovers above 95%
The cohort-aligned cue-coverage recovery check confirms the fix branch landed; the mid-roll cue lands on the program-return anchor instead of slate before the next ad break.
- ReportPostmortem in Slack + Linear
Structured write-up with the cue-pass split, the slate-duration envelope, and the agentic-act split lands in the channel with the affected FAST lane and mid-roll ad break flagged.
Medians across the current Streamwake cohort, refreshed on the quarterly streaming-reliability benchmark — the relationship to fix-branch selection holds at long-running linear channel scale, with the largest effects seen in identifying the affected FAST lane before the primetime mid-roll ad-break window opens.
Fewer 3 a.m. pages.
A team that sleeps.
Streamwake is in early access for FAST channels and ad-supported linear cohorts running long-running on-air lanes. Run the Free Stream Check on any FAST channel, or pull up the ROI calculator to model your primetime mid-roll ad-break incident load and MTTR curve.