Working Within Claude Code's Context Window
Long sessions degrade. Here's how to keep Claude effective as context fills up — and when to start fresh.
Claude Code sessions get less effective as they get longer. This isn't a bug — it's just how context windows work. The model has to attend to everything in context, and as the window fills with old code, old errors, and old attempts, the signal-to-noise ratio drops.
Here's how I manage context to keep sessions sharp.
Know the signs of context degradation
The first sign is usually repetition — Claude suggests something you already tried, or asks you to confirm something you already confirmed. The second sign is drift — the output stops following your established patterns and starts reverting to generic style. The third is hallucination uptick — wrong function names, wrong file paths, inventing APIs that don't exist in your codebase.
When I see any of these, I don't keep pushing. I compact or start a new session.
Front-load context, don't accumulate it
The most common mistake in long sessions is letting context accumulate passively — pasting errors, pasting file contents, asking follow-up questions. Each exchange adds tokens, and after an hour the model is carrying all of it.
Better approach: at the start of each session, give Claude a precise summary of what matters. What files are in scope. What patterns the codebase uses. What you're building today. Then work in focused bursts on one thing at a time.
Use /compact strategically
In Claude Code, /compact summarizes the conversation and resets the active context. I use it when:
- A subtask is done and I'm moving to the next one
- I've resolved a bug and want to start fresh on the next feature
- Context is around 60-70% full (before it starts degrading, not after)
After compacting, the summary Claude generates is usually good enough to carry the essential state forward. If there's something critical that might get lost, I write it to a file before compacting so I can paste it back if needed.
Keep a task state file
For multi-session work, I keep a simple markdown file that tracks what I'm building, what's done, and what's next. When I start a new session, I paste that file into the first message. Claude picks up where the previous session left off without needing the full history.
This also means container restarts and context resets don't lose work — the state file is the persistent record, not the conversation.
Scope sessions by task, not by time
A session should have a clear scope: "implement the pagination component" or "debug the auth token refresh." When that scope is done, the session is done. Starting a second thing in the same session because you still have context budget left is how sessions become unfocused.
Fresh context is free. Use it.