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Matthew Fontana
Matthew Fontana

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Taming Context Windows: Disable Auto-Compact for Better AI

Have you ever been deep in a coding session with Claude, everything flowing perfectly, when suddenly you see that dreaded message: "compacting..."?

Your heart sinks. You know what's coming next. The quality drops. The responses get vaguer. What was once a brilliant coding partner just got noticeably... dumber.

This isn't your imagination. It's a fundamental constraint of AI coding tools, and understanding it is the difference between fighting your tools and designing workflows that actually work.

Building with AI agents? I'm documenting everything I learn about agentic engineering at The Agentic Engineer—from Claude Code workflows to shipping full-stack SaaS in an afternoon. Come for the tutorials, stay for the "wait, you can do that?" moments.

The Hidden Cost of Auto-Compact

Let's run a quick experiment. Start a fresh Claude Code session and run these commands:

/prime          # Load your codebase context
/context        # Check context window usage
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Here's what you'll see:

Claude context window breakdown showing auto-compact buffer usage

Notice anything alarming? The auto-compact buffer is consuming 22.5% of your available context window — that's 45,000 tokens out of 200,000 — before you've even started coding.

What Is Auto-Compact?

Auto-compact is Claude's safety mechanism. When your conversation history approaches the context limit, Claude automatically:

  1. Compresses older messages into summaries
  2. Discards details it deems less relevant
  3. Continues the conversation without hitting a hard limit

This sounds great for interactive chat sessions. But for agentic coding workflows? It's a silent performance killer.

Why Context Loss Makes AI "Dumber"

Every time Claude compacts, you lose information. Not just any information — often the precise technical details that matter most:

  • Variable names get generalized to "the variable"
  • Specific error messages become "some errors occurred"
  • Architecture decisions fade into "we discussed this earlier"
  • Code patterns you established get forgotten

The more you compact, the vaguer everything becomes. This is why long coding sessions feel like they degrade over time. You're literally watching the AI forget.

The Traditional Flow: Fighting the Context Window

Most developers use AI tools in a continuous, linear flow:

Start session → Code → Code → Code → Compact → 
Code (worse) → Compact → Code (even worse)
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This "in-the-loop developer flow" is typical of agentic coding. You're constantly building context, asking questions, making changes, all within a single session.

The problem: You're trapped in one context window that keeps degrading.

The Agentic Engineering Solution: Workflow Composition

Here's the shift: Stop trying to do everything in one session.

Instead of fighting the context window, design workflows that externalize state and compose cleanly:

/prime → /plan → save plan.md → /clear
/implement plan.md → save code → /clear
/test plan.md → save results → /clear
/review plan.md → save feedback → /clear
/document plan.md code/ → save docs
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Each workflow:

  • Starts fresh with maximum context available
  • Reads its inputs from files (plan, code, specs)
  • Writes its outputs to files (code, tests, docs)
  • Never compacts because it finishes before hitting limits

The Power of File-Based State

Instead of relying on conversation history, you rely on artifacts:

  • Plan files capture decisions and architecture
  • Code files are the source of truth
  • Test results document what works
  • Review comments track quality checks

Each new Claude session reads these artifacts and has full context of what matters, without the accumulated noise of every conversational back-and-forth.

Turning Off Auto-Compact

If you're designing standalone workflows, you don't want that 22.5% buffer eating your context:

  1. Open Claude Code settings
  2. Find the Auto-Compact toggle
  3. Turn it off

Now check your context again with /context:

Context window after disabling auto-compact, showing 22.5% more available space

You just gained back 45,000 tokens — over a fifth of your total context window.

When to Use This Setting

Turn OFF auto-compact when:

  • Building standalone workflow commands
  • Each task has a clear output artifact
  • You're okay with sessions ending when context is full

Keep auto-compact ON when:

  • Doing exploratory coding with no clear endpoint
  • Having long conversational debugging sessions
  • You need the session to continue indefinitely

Designing Context-Efficient Workflows

Here's how to structure your workflows for maximum AI intelligence:

1. One Job Per Session

Don't ask Claude to plan, implement, test, and document in one go. Each of these is a separate workflow:

# Planning session
/prime
/plan "Add user authentication"
# Outputs: plan.md

# Implementation session
/clear  # Start fresh!
/implement plan.md
# Outputs: code changes

# Testing session
/clear
/test plan.md
# Outputs: test results
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2. Push Context to Files

Every workflow should produce an artifact:

## plan.md
- Add JWT authentication
- Use bcrypt for password hashing
- Implement rate limiting
- Add password reset flow
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Now your next session can read plan.md and has perfect context without conversational drift.

3. Compose Workflows Like Functions

Think of each workflow as a pure function:

plan(requirements) → plan.md
implement(plan.md) → code/
test(plan.md, code/) → results.md
review(plan.md, code/) → feedback.md
document(plan.md, code/) → docs/
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Each function:

  • Has clear inputs (files)
  • Produces clear outputs (files)
  • Doesn't depend on previous conversation state

Real-World Example: My Blog Workflow

I use this pattern for generating blog posts:

# One workflow: Create post
/create-post "Context window management"
# Outputs:
# - website/content/posts/2025-11-03-context-windows.mdx
# - website/public/blog/2025-11-03-context-windows/hero.webp

# Separate workflow: Quality review
/clear
/mdx-quality-review website/content/posts/2025-11-03-context-windows.mdx
# Outputs: SEO report, Vale linting results

# Separate workflow: Git deployment
git add .
git commit -m "Add post about context management"
git push
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Each slash command is a standalone workflow. They don't share conversation state. They read from and write to files.

Result? Every workflow runs with maximum context and intelligence.

The Memory Constraint Reality

Here's the truth: AI tools are incredibly intelligent, but their memories are very limiting.

No matter how smart Claude gets, it's still bound by:

  • 200K token context windows (for now)
  • Information loss during compaction
  • Degraded quality over long sessions

We can't change these constraints (yet). But we can design around them.

Key Takeaways

  1. Auto-compact costs you 22.5% of your context window before you start
  2. Every compact loses information and makes responses vaguer
  3. Long sessions degrade because the AI is literally forgetting details
  4. File-based workflows let you compose clean, standalone tasks
  5. Turning off auto-compact gives you more power per session, but requires workflow discipline

Quick Tips for Context Management

  • ✅ Use /context regularly to check your usage
  • ✅ Turn off auto-compact for workflow-based coding
  • ✅ Start new sessions for each major task
  • ✅ Push important decisions to plan files
  • ✅ Let workflows read files instead of relying on conversation history
  • ✅ Think of Claude sessions as stateless functions

The Future

One day, AI tools might have perfect context management. Infinite windows. Zero information loss.

Until that day, design your workflows around the constraints.

The developers who understand context windows aren't fighting their tools — they're architecting workflows that maximize every available token.


Did this help you rethink your AI coding workflow? Want more tips check out The Agentic Engineer

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