Claude Clue #6: Your Context Window Is Already 30% Full

Ever wonder why your Claude conversation seems to "forget" things faster than you expected? Here's the thing: that 200K context window isn't actually 200K of space for your conversation. Before you type a single word, system prompts and built-in tools eat up about 7-8% of the space. Then there's the autocompact buffer—that's another 22.5% reserved so Claude can summarize your conversation and finish tasks without stopping mid-action. You're really starting with about two-thirds of what's advertised. Add in your MCPs and custom instructions, and that number drops further.

I discovered this after switching my Claude Code setup and finally running the /context command. It's like opening the hood on a car you've been driving for months—suddenly you understand why it handles the way it does. Claude Desktop doesn't show you this stuff, but Claude Code gives you real visibility into where your tokens are going. If you're on an API plan, you get the full breakdown including costs. Team plan gives you less detail but still way more than flying blind. Next time a conversation feels like it's losing the plot earlier than expected, now you know where to look.

For more about context, check out AEH Episode 48 - Pass The Note

Human ideas, AI-assisted polish.