What is an ACK timeout breach in merge queue governance?

An ACK timeout breach occurs when the assigned owner fails to acknowledge an escalation alert within the agreed time window, which leaves incident decisions unowned and increases repeat-risk in rollback windows.

Which timer should start first during an escalation incident?

Start the acknowledgement timer first, then the action timer after acknowledgement, and run a leadership timeout in parallel as the safety rail if acknowledgement never arrives.

How many escalation tiers should teams use for ACK breaches?

Most teams can use three tiers: primary responder, secondary on-call, and incident/governance lead as final tie-break owner.

What evidence is required before closing an ACK timeout breach?

Record breach timestamp, paging evidence, owner handoff timestamps in UTC, remediation actions taken, and confirmation that baseline protections and required checks were restored.

How do you prevent recurring ACK timeout breaches?

Use a weekly closure-quality review that tracks ACK SLA misses by team and service, then trigger ownership corrections when the miss rate crosses your recurring-incident threshold.

GitHub Merge Queue Escalation ACK Timeout Remediation Runbook: On-Call Handoffs, Breach Timers, and Recovery Templates (2026)

Published February 18, 2026 · 11 min read

Most merge queue incident playbooks define who to page. Fewer define what to do when nobody acknowledges the page on time. ACK timeout breaches are where ownership fails silently and rollback windows remain exposed.

This guide gives a practical ACK-timeout remediation runbook for GitHub merge queue governance: timer model, escalation tiers, handoff expectations, and copy-paste communication templates.

⚙ Quick links: Threshold Alert Routing Playbook · Closure Quality Metrics Dashboard · Approval Evidence Template Guide · Denial Appeal Escalation Path Guide · Expiry Extension Reapproval Guide

Why ACK timeout breaches are high-risk
Three-timer model for escalation governance
Severity thresholds and ACK SLA targets
Escalation path and owner handoff matrix
15-minute remediation workflow
Copy-paste communication templates
Anti-patterns and guardrails
FAQ

1. Why ACK timeout breaches are high-risk

A missed acknowledgement is not just a paging issue. It means incident ownership is undefined while branch-protection exceptions are still active, required checks are still unstable, or recovery decisions are still pending.

Failure pattern	What usually happens next	Control you need
Primary owner silent past ACK window	Informal chat escalation with no timestamp trail	Automatic tier handoff at timeout boundary
Multiple responders answer late	Duplicate actions and conflicting decisions	Single acting owner declaration macro
No leadership fallback trigger	Incident drifts beyond rollback-safe window	Parallel leadership timer with hard cutover

Critical rule: treat ACK timeout as a governance breach event, not an operator preference issue. The breach itself should create a trackable record.

2. Three-timer model for escalation governance

Run three explicit timers from the moment the first escalation alert is sent. This prevents ownership ambiguity and avoids silent waiting loops.

Timer A

ACK timer

How long the assigned owner has to acknowledge and claim execution.

Timer B

Action timer

How long after ACK to post first concrete remediation action in the PR timeline.

Timer C

Leadership timer

Independent timeout that triggers governance lead takeover if A or B is missed.

Implementation tip: start all three timers at once in your incident bot payload, but only surface Timer B after ACK. This keeps the model simple and auditable.

3. Severity thresholds and ACK SLA targets

ACK windows should scale by impact. Use severity mapping that is short enough to stop drift but realistic for your on-call coverage model.

Severity	ACK SLA	Action SLA	Leadership cutover
SEV-1 production rollback blocked	5 minutes	10 minutes from ACK	15 minutes from initial alert
SEV-2 merge queue unstable, safe rollback path exists	10 minutes	20 minutes from ACK	30 minutes from initial alert
SEV-3 policy drift risk, no active customer impact	20 minutes	40 minutes from ACK	60 minutes from initial alert

These values are starting points. Calibrate weekly with your closure-quality dashboard and adjust only with explicit owner sign-off.

4. Escalation path and owner handoff matrix

The path must be deterministic: each timeout has one destination owner and one expected action. No "whoever is online" routing.

Timeout event	Escalates to	Expected action	Evidence required
ACK timer breached (Timer A)	Secondary on-call owner	Post owner-claim comment and begin action plan	UTC breach timestamp + pager receipt
Action timer breached (Timer B)	Incident commander	Take execution ownership and publish decision path	Missing-action proof + command takeover note
Leadership timer breached (Timer C)	Governance lead / manager on duty	Authorize bounded exception or enforce baseline restore	Risk justification + expiry + restoration plan

5. 15-minute remediation workflow

When ACK SLA is missed, run this sequence as a fixed protocol. Avoid ad-hoc negotiation until after ownership is restored.

Declare breach: post ACK-timeout breach comment with exact UTC timestamp.
Trigger handoff: page tier-2 owner and assign acting owner immediately.
Freeze ambiguity: record one acting owner in PR to avoid parallel decision makers.
Reconfirm risk: summarize current merge queue risk and rollback status in two to three lines.
Start action timer: set new action SLA checkpoint from handoff acceptance time.
Escalate if needed: if first action is missed, route to incident commander without debate.
Close with proof: finalize timeline with all breach and handoff timestamps.

Short principle: speed without timeline evidence creates future disagreement. Every handoff must have one UTC timestamp and one named owner.

6. Copy-paste communication templates

Use these templates directly in PR comments or incident channels to keep language consistent.

Template A: ACK timeout breach notice

[ACK TIMEOUT BREACH]
Incident: <id>
Severity: <SEV-1/2/3>
Primary owner: @<handle>
ACK deadline (UTC): <yyyy-mm-dd hh:mm>
Breach detected (UTC): <yyyy-mm-dd hh:mm>
Next owner (tier-2): @<handle>
Requested action: claim ownership and post first action within <N> min.

Template B: Tier handoff confirmation

[HANDOFF ACCEPTED]
Acting owner: @<handle>
Accepted at (UTC): <yyyy-mm-dd hh:mm>
Action deadline (UTC): <yyyy-mm-dd hh:mm>
Current risk summary:
- <required checks state>
- <rollback status>
- <branch protection exception state>

Template C: Leadership cutover

[LEADERSHIP CUTOVER]
Cutover trigger: <Timer B breach / Timer C breach>
Cutover owner: @<handle>
Cutover time (UTC): <yyyy-mm-dd hh:mm>
Decision needed: <bounded extension / enforce baseline restore / rollback path>
Decision deadline (UTC): <yyyy-mm-dd hh:mm>
Evidence links: <links>

Template D: Breach closure record

[ACK BREACH CLOSURE]
Incident: <id>
Initial breach at (UTC): <yyyy-mm-dd hh:mm>
Final owner: @<handle>
Remediation completed at (UTC): <yyyy-mm-dd hh:mm>
Restoration proof: <required checks + protection baseline links>
Follow-up owner: @<handle>
Follow-up due (UTC): <yyyy-mm-dd hh:mm>

7. Anti-patterns and guardrails

Anti-pattern	Why it fails	Guardrail
Waiting "a bit longer" after timeout	Extends unowned risk window	Auto-handoff trigger with no manual approval
Escalation in private chat only	No audit trail and unclear accountability	Mandatory PR timeline update before action
Multiple responders acting simultaneously	Conflicting rollback decisions	Single acting-owner declaration per phase
No post-breach review	Same team keeps missing ACK SLA	Weekly threshold review with ownership correction

FAQ

Should ACK timeout always trigger leadership escalation immediately?

Not always. Route first to tier-2 ownership if your timer model includes it, but leadership cutover should still be pre-timed and automatic if tier-2 fails.

Do we need separate timers for weekdays and weekends?

You can vary SLA values by staffing model, but keep the same timer structure and escalation path so responders do not relearn the process during incidents.

How do we measure if this runbook works?

Track ACK timeout frequency, median handoff completion time, repeated timeout rate by team, and closure completeness for breached incidents.

Can this runbook be used outside merge queue incidents?

Yes. The same timer and handoff model can be used for any incident class where delayed acknowledgement creates operational risk.

What is the minimum governance record for compliance reviews?

At minimum: initial alert timestamp, ACK deadline, breach timestamp, owner handoffs, final decision, and restoration proof links.

ACK timeout breaches are predictable. Treat them as first-class governance events, automate the handoff path, and keep timeline evidence strict. This is how you stop silent ownership failures from becoming recurring incidents.