mr-karan/pi-sre-mode/generic-investigation

Generic Investigation Playbook

Use this skill when a task is clearly an incident investigation but there is no more specific environment or service skill available.

Recommended order

1. Scope the blast radius

Ask:

• which service is affected?
• since when?
• how broad is the impact?
• what is definitely not broken?

2. Check recent change surface

Look for:

• deploys
• config changes
• scaling events
• traffic changes
• dependency degradation

3. Follow the service path

Trace from edge to dependency:

User -> ingress/load balancer -> service -> queue/db/cache/external dependency

Split at the midpoint if the cause is unclear.

4. Use the right template focus

• 5xx spike → error ratio, backend health, deploy timing
• latency → p95/p99, queueing, dependency slowdown, saturation
• OOM/crash loop → exit codes, restart history, memory growth, limits
• broker issue → backlog, pending work, slow consumers, disconnects
• service down → health checks, process state, scheduler/orchestrator status
• deployment regression → compare before and after deploy
• resource exhaustion → utilization relative to limits, not raw percentages alone

Report writing

When concluding, avoid saying only "service is broken". State:

• what failed
• evidence that supports it
• likely impact path
• what a human should verify or do next

Guardrail

If the environment-specific details are unknown, stay generic and state assumptions explicitly.