Managing Your Context Window

The context window is Claude's working memory. Your conversation, file reads, command outputs and system prompts ALL live in this one fixed-size space. Handle it well and you get a productive 30-minute session. Handle it badly and Claude starts losing the plot after 10.

What Consumes Context#

Some things eat way more context than others.

Signs of Context Degradation#

Keep an eye out for these.

• Claude "forgets" something you told it earlier
• Answers get vaguer and more generic
• Claude re-reads files it already read
• The quality of its edits slips
• Claude starts guessing when it should be checking

/compact: Your Best Friend#

The /compact command squishes the conversation down into a summary while hanging on to the important stuff. Reach for it when any of these happen.

• Context usage hits 60-70%
• You just wrapped one subtask and you're starting another
• Claude just read a bunch of big files
• Wordy command outputs have bloated things

What /compact keeps.

• Key decisions made during the conversation
• File paths and functions you talked about
• The current task and where it stands
• Recent edits and why they were made

What /compact tosses.

• Detailed file contents (Claude can re-read them if needed)
• Wordy command outputs
• Old reasoning that doesn't matter anymore
• Repeated or redundant info

/clear: The Fresh Start#

Use /clear in these situations.

• You're switching to a totally unrelated task
• The conversation has gone off the rails
• Context is above 80% and even /compact won't free up enough
• You want to try a different approach from scratch

Subagents for Context Isolation#

When Claude uses the Agent tool to spawn a subagent, that agent gets its own context window. That's handy for a few things.

• Exploring big codebases without cluttering your main session
• Running complicated searches that spit out a ton of output
• Handing off independent subtasks

The subagent only reports back a summary, so your main context stays clean.

The One-Task-Per-Session Pattern#

Here's the context strategy that works best, hands down.

1. Start a session with one clear goal
2. Give Claude the task
3. Let it finish the task
4. End the session (or /clear for the next task)

Why this works.

• All of Claude's context is focused on one thing
• Nothing unrelated is fighting for attention
• The results stay consistently good
• You never hit the foggy zone halfway through a task

Practical Context-Saving Tips#

1. Give File Paths Upfront#

# Context-expensive (Claude searches)
"Fix the bug in the login form"
 
# Context-cheap (Claude goes straight there)
"Fix the TypeError in src/components/LoginForm.tsx line 42"

2. Limit Output Verbosity#

When you run commands, pipe them to head or use flags that cut down the output.

# Instead of: npm test (which might dump 500 lines)
# Use: npm test -- --reporter=dot (minimal output)

3. Be Concise in Your Prompts#

Every word you type costs context. Check out the difference.

# Verbose (wastes context)
"Hey Claude, I was wondering if you could please take a look at
the authentication middleware and maybe if you have time could you
add some rate limiting to prevent abuse? I think that would be
really helpful for our production deployment."
 
# Concise (same request, less context)
"Add rate limiting to the auth middleware in src/middleware.ts.
Use 100 requests per minute per IP."

Same request, half the words. (Being polite to the robot is sweet, it's just not free.)

4. Don't Ask Claude to Explain Unless You Need It#

"Add the feature" uses less context than "Add the feature and explain every decision." Save the explanations for when you're actually trying to learn something.

Monitoring Your Context#

Run /context regularly. It draws a lil grid of what's filling your context window and suggests ways to free up space. Here's how to read the numbers.

• 0-40%. Tons of room. Work like normal.
• 40-60%. Healthy range for mid-task work.
• 60-70%. Start thinking about /compact.
• 70-85%. Compact now. Quality might already be slipping.
• 85%+. Compact right away or /clear. You're deep in foggy territory...

If you let it fill all the way up, Claude Code compacts automatically so your session doesn't just die. Doing it yourself first is still better, because you pick the moment (and you can tell /compact what to focus on).

TL;DR#

• The context window is limited working memory, and everything lives there
• File reads and command outputs are the biggest context hogs
• Use /compact at 60-70% to free up space and keep the important stuff
• Use /clear when you switch to an unrelated task
• Subagents keep exploratory work out of your main context
• One task per session is the safest way to keep quality high
• Give file paths and keep it short to avoid wasting context