Claude Code: Context Window Reset Bug After /clear

Hey everyone, let's dive into a little hiccup we've found with Claude Code CLI, specifically when it comes to how it tracks our context window. You know, that crucial piece of info that tells us how much of Claude's memory we're using up in our current chat? Well, it turns out there's a bug where this tracking doesn't quite reset like we'd expect after using the /clear command. This can be super confusing because we think we're starting fresh, but the numbers are still showing a high usage from previous chats. It’s like trying to start a new game, but the score from the last one is still displayed!

Why Context Window Tracking Matters

Alright guys, let's talk about why this context window tracking is a big deal for us using Claude Code CLI. Think of the context window as Claude's short-term memory. It’s how much information Claude can actively consider when you're chatting with it. When you send a message, it takes up some of that space. When Claude responds, that also uses up space. The total_input_tokens and total_output_tokens are supposed to give us a heads-up on how much of this memory we've used up in our current conversation. This is super important because there are limits to this memory. If we go over, Claude might start forgetting earlier parts of our chat, or we might hit a hard limit that stops the conversation altogether. So, having an accurate, real-time view of this is essential for managing our interactions effectively. We want to know if we’re approaching the edge, so we can maybe summarize things, prune unnecessary details, or just be aware that Claude might not remember the very beginning of a long discussion. Without this accurate tracking, we're kind of flying blind, which isn't ideal when you're trying to build something complex or have a nuanced conversation.

The Problem: Context Window Confusion After /clear

So, here's the juicy bit, the actual bug we're seeing. When you're in a session with Claude Code CLI, and you’ve been going back and forth, building up a good chunk of conversation, you'll notice the statusline shows your total_input_tokens and total_output_tokens. This gives you a snapshot of your current memory usage. Now, if you decide to start fresh, maybe because the conversation went in a weird direction or you just want a clean slate, you hit that /clear command. Logically, /clear should, well, clear everything and start a brand new conversation, right? This means Claude should have its full memory available again, and our token count should reset to pretty much zero (just the initial system prompt tokens). However, that’s not what’s happening. Instead of resetting, the total_input_tokens and total_output_tokens just keep on ticking up, accumulating from previous conversations within the same CLI session. It’s like running a marathon, crossing the finish line, and then starting another race right away, but the timer from the first race is still running and adding to your overall time. This means the statusline keeps showing a high context usage, even though you've explicitly told it to start over. This is a bummer because it completely defeats the purpose of /clear for managing your context window. You might think you're being mindful of your limits, but in reality, the numbers are skewed, and you might be much closer to hitting a limit than you realize.

Expected vs. Actual Behavior: What We Want vs. What We Get

Let's break down what we expect to happen when we use /clear versus what's actually going down. Our expected behavior is pretty straightforward, guys. After we type /clear and hit enter, we anticipate a clean slate. This means our context window usage, represented by total_input_tokens and total_output_tokens, should reset. It should go back to a minimal value, representing just the baseline system prompt that Claude uses to understand its role and instructions. This is because the /clear command is designed to discard the current conversation history and initiate a new, independent chat session. In this fresh session, Claude should have access to its entire context window capacity again, free from the baggage of past exchanges. It’s the logical outcome of wanting to start anew.

Now, for the actual behavior, it’s a bit of a curveball. Instead of resetting, the total_input_tokens and total_output_tokens values continue to accumulate. They don't just track the current conversation; they seem to be tracking the cumulative usage across your entire CLI session, even across multiple /clear commands. So, if you had a long conversation, cleared it, and then started a new one, the token count shown in the statusline will still reflect the combined usage of both. This leads to the statusline showing a high context usage percentage that remains unchanged even after you’ve gone through the process of clearing the conversation. It’s misleading because it gives the impression that you're deep into your context limit, when in fact, the current conversation might be using very little. This discrepancy is the core of the problem and makes it hard to rely on the statusline for making informed decisions about conversation length and context management.

Steps to Reproduce: Let's See It in Action!

Okay, so you want to see this bug for yourselves? It's pretty easy to reproduce, guys. Just follow these simple steps, and you'll see exactly what we're talking about. This will help us all get on the same page about the issue.

1. Start a Claude Code session: The first thing you need to do is actually start up the Claude Code CLI. You'd typically do this by typing claude in your terminal and hitting enter. This gets the environment ready for our chat.
2. Have a conversation that uses significant context: Now, this is where you build up some data. Start chatting with Claude. Ask it questions, give it code to analyze, ask for explanations, whatever you need to do. The key here is to have a conversation that generates a decent amount of input and output tokens. We're not talking about a quick