Capture it where it's already written: resolved tickets, internal notes, and Slack threads. Then ask your experts to narrate the tricky areas while they work, and turn repeated answers into runbooks.
Practical sources
- Resolved escalations and their root causes
- Internal notes on long-running tickets
- Engineering answers in support channels
- Recorded walkthroughs from your most senior people
Reducing the need for it
A lot of tribal knowledge is about how the code actually behaves. Tools that read the code directly need less of it.
Decimal learns from resolved tickets and reads the code, so that knowledge is available on every ticket. See tribal knowledge and runbook.