[BUG] The math for `/context` doesn't add up correctly

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude version

claude --version
2.0.1 (Claude Code)

Issue

The free space calculation in /context seems wrong:

> /context 
  ⎿  Context Usage 60k/200k tokens (30%)
     ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛝ ⛝ ⛝ 
     ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ 
     ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝ ⛝   ⛁ System prompt: 3.0k tokens (1.5%)
     ⛀ ⛀ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶   ⛁ System tools: 11.5k tokens (5.8%)
     ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶   ⛝ Reserved: 45.0k tokens (22.5%)
     ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶     [autocompact + output tokens]
     ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶   ⛁ Memory files: 271 tokens (0.1%)
     ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶   ⛁ Messages: 91 tokens (0.0%)
     ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶   ⛶ Free space: 95k (47.6%)
     ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ ⛶ 

     Memory files · /memory
     └ Local                                                              271 tokens
     (.../CLAUDE.local.md):

     SlashCommand Tool · 0 commands
     └ Total: 757 tokens

The 60K of Context Usage seems to be System prompt + System tools + Reserved + Memory files + Messages.

Then Free space should be 140K (200K - 60K) - not 95K as the display states.

NOTE: I simply ran claude on the terminal. I did not pass any arguments like --continue or --resume.

What Should Happen?

Then Free space should be 140K (200K - 60K) - not 95K as the display states.

Error Messages/Logs

Steps to Reproduce

Type /context in a claude session (no extra command line args) and check the math of Free space.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.0.0

Claude Code Version

2.0.1

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Warp

Additional Information

_No response_