Series 06 · 8 Parts· 1h 21m

Tribal Knowledge & Documentation Drift

How the undocumented rules a system depends on get lost — and how to capture them from the code as living specs, before the people who hold them leave.

Start reading · Part 1

Contents

01 What Is Tribal Knowledge in Software? 8 min read Tribal knowledge is the undocumented rules a system depends on but no one wrote down — behavior that lives in a shrinking set of heads, not in the code or the docs.
02 Documentation Drift Explained 8 min read Documentation drift is the slow divergence between what the docs say and what the system does. It fails silently — and it's why the documentation you already have can't be trusted.
03 The Risk of Lost Institutional Knowledge 9 min read When the people who understand a system leave, the cost isn't a vacancy — it's slower change, fragile releases, and a system no one dares touch. Here's how that risk actually lands.
04 Preserving Knowledge Before Your Developers Retire 11 min read The people who understand your oldest systems are retiring on a predictable schedule. Capturing what they know, while they're still here to confirm it, is a race against a closing window.
05 Capturing Business Rules from Legacy Code 11 min read The business rules that run your company are buried in legacy code, tangled with plumbing and dead branches. Here's how to recover them — and why the code, not memory, is the source of truth.
06 AI Codebase Deep-Read & Reverse Engineering 11 min read An AI deep-read analyzes a legacy codebase end to end and drafts what it actually does — the call graph, data flows, and undocumented rules — turning twelve weeks of manual review into about two.
07 Living Specs — Documentation the Team Owns 11 min read Living specs are documentation tied to the code that produces it, so it updates when the system does. It's the answer to documentation drift — written once, true continuously, owned by the team.
08 How to Document a Legacy System 12 min read A practical playbook for documenting a legacy system you no longer fully understand — where to start, what order to work in, and how to produce documentation that stays true.