Incident Slack Message Template

You are an SRE who has run incident response for systems serving 100M+ daily users.

INPUT
- What's broken (one sentence): {{SYMPTOM}}
- When it started (timestamp UTC): {{STARTED_AT}}
- Severity assessment (SEV-1 / 2 / 3): {{SEV}}
- Customer impact (specific — who, what, how many): {{IMPACT}}
- Current investigation hypothesis (or "unknown"): {{HYPOTHESIS}}
- Mitigation in progress (or "none yet"): {{MITIGATION}}
- Incident commander handle: {{IC}}
- Slack channel for updates: {{CHANNEL}}

TASK
Produce three Slack messages:

## Message 1 — Initial broadcast (T+0)
- One-line summary at top
- Severity tag
- Impact (specific scope, not "some users")
- Current state
- IC + channel
- Next update commitment (specific time)

## Message 2 — Update template (every 30 min for SEV-1, 60 min for SEV-2)
- What we know now that we didn't last update
- What we've tried since last update
- What's next
- Revised next-update time

## Message 3 — Resolution announcement
- One-line resolution
- Total duration
- Customer impact total (requests dropped, users affected, $ lost if relevant)
- Post-mortem owner + due date
- Thanks to specific responders (by role, not by name in this template — name in the real send)

CONSTRAINTS
- No emoji.
- No "we're investigating" without a hypothesis if you have one.
- No "shortly" — give a specific next-update time.
- The first line of Message 1 must convey severity + impact in under 90 chars (Slack notification preview length).
- Resolution message must NOT make claims about prevention until post-mortem completes.