Understanding Context
What Claude knows, what it forgets, and how to help it help you.
How Claude sees your work
When you start a session, Claude builds up a mental picture from several sources:
- CLAUDE.md files — Read automatically when you start
- Files you mention — When you reference or ask about them
- The conversation — Everything said in this session
- What it’s discovered — Results from searches and commands
This is what Claude “knows” at any moment. Understanding how it works helps you work together more effectively.
The forgetting problem
Claude has a limited memory — roughly 200,000 tokens of context. That sounds like a lot, but long conversations fill it up.
When context fills up:
- Older parts of the conversation get summarized
- Details from earlier may be compressed
- Claude might “forget” things you discussed
Signs you’re hitting limits:
- Claude asks questions you already answered
- Suggestions conflict with earlier decisions
- Claude seems to have forgotten the goal
What stays, what fades
| Information | When it’s available | How strongly |
|---|---|---|
| CLAUDE.md | Always | High priority |
| Recent conversation | Always | High priority |
| File you just mentioned | When relevant | High priority |
| Earlier conversation | Summarized | Lower priority |
| Old details | May be compressed | Lowest priority |
Helping Claude remember
Put important things in CLAUDE.md. Information there is always available, not subject to forgetting.
Be explicit about files. Instead of “check the notes,” say “read Notes/project-plan.md.”
Summarize after long discussions. “So we’re going with the simple approach, keeping everything in one folder.”
Start fresh when needed. If a conversation has gone off track, a new session with good CLAUDE.md context is often cleaner than continuing.
The key insight
Claude doesn’t have perfect memory. It has weighted attention — recent and explicit information matters more than old implicit information.
For developers
When working with code, context matters even more:
| Source | When included | Priority |
|---|---|---|
| CLAUDE.md | Always, at session start | High |
| Current file | When you’re editing | High |
| Grep/Glob results | When searching | Medium |
| Older conversation | Summarized | Low |
Large codebases fill context quickly. Keep CLAUDE.md focused on what matters, reference files explicitly, and don’t be afraid to start fresh sessions for new tasks.
Official Documentation
- Context windows — How Claude manages conversation context and token limits