Why Your Claude Code Sessions Keep Losing Context (And How to Fix It)

Why Your Claude Code Sessions Keep Losing Context (And How to Fix It) Context loss is the most common productivity killer in long Claude Code sessions. You start with a clear plan, 45 minutes in Claude has forgotten key decisions, and you're re-explaining things you already covered. Here's what's actually happening and the structural fixes that eliminate it. What Causes Context Loss Claude Code has a finite context window. In long sessions: Early files get compressed — the model's effective attention on files read 30 minutes ago degrades Implicit decisions aren't retained — if you said "use Zod for validation" in conversation, that can drift out of focus Error history gets lost — Claude stops connecting current errors to past ones you already fixed This isn't a bug. It's how transformer models work. The fix is structural, not prompt-based. Fix 1: The Session Spec File Create .claude/session.md at the start of every significant work session: # Session: Auth System Refactor Date: 2026-04