> Term
source of truth drift
The divergence between documentation, system diagrams, and the actual live codebase over time.
Detailed Explanation
The inevitable decay of accuracy where architecture diagrams, wikis, and design documents slowly stop matching what is running in production.
Without automated diagramming or disciplined update cultures, the 'source of truth' becomes a source of lies, confusing onboarding engineers and causing deployment accidents.
Why It Matters
It creates a dangerous illusion of understanding. Engineers make architectural decisions based on diagrams that no longer represent reality.
Common Failure Mode
Practical Example
Production Manifestation
Outdated Confluence pages, stale OpenAPI specs, and system models that don't show the three databases added last year.
Frequently Asked Questions
What is source of truth drift in short?
The divergence between documentation, system diagrams, and the actual live codebase over time.
What is the most common failure mode?
A new developer references an old schema document and drops a column they believe is unused, immediately bringing down the billing service.
AI Summary
The divergence between documentation, system diagrams, and the actual live codebase over time. It creates a dangerous illusion of understanding. Engineers make architectural decisions based on diagrams that no longer represent reality.