[BUG] v2.1.111 with Opus 4.7 consumes ~1.7–2x more context tokens than v2.1.110 on a fresh session

What's Wrong?

Claude Code v2.1.111 consumes roughly ~1.7x the context tokens of v2.1.110 on a fresh session for the same minimal task (read a ~100-line markdown file).

Measured on my ~/.claude directory:

• v2.1.110 + Opus 4.6 → ~21.5k tokens
• v2.1.111 + Opus 4.7 → ~36.7k tokens

Same repo, same prompt, clean session, no prior conversation.

In another repository the gap is even larger — ~20k vs ~40k tokens (~2x).

I also compared with Haiku across both CC versions: the new version is consistently heavier, though the absolute delta with Haiku is smaller than with Opus. This suggests the increase is driven primarily by the Claude Code harness (system prompt, tools, skills, MCP descriptors) rather than by the model itself.

What Should Happen?

A fresh session in v2.1.111 should consume roughly the same context as v2.1.110 (~21.5k tokens in my setup). A ~1.7–2x jump for an identical task is a significant regression in effective context budget and cost.

Steps to Reproduce

1. Install @anthropic-ai/claude-code@2.1.110, start a clean session, select Opus 4.6 via /model.
2. Run a trivial prompt such as read ~/.claude/learnings/tmux-quickstart.md (any ~100-line markdown file).
3. Run /context and record the total tokens used.
4. Install @anthropic-ai/claude-code@2.1.111, start a clean session, select Opus 4.7 via /model.
5. Run the exact same prompt on the same file.
6. Run /context and compare.

Observed in my setup (v2.1.111 /context breakdown, 36.7k total):

• System prompt: 8.3k
• System tools: 13.7k
• Custom agents: 0.6k
• Memory files: 4.2k
• Skills: 2.9k
• Messages: 7.1k
• Compact buffer: 3.0k

The system tools (13.7k) and system prompt (8.3k) figures look notably higher than what I saw on v2.1.110 under the same configuration.

Claude Model

Opus (primary comparison); also reproduced with Haiku at a smaller delta.

Is this a regression?

Yes, this worked in a previous version.

Last Working Version

2.1.110

Version

2.1.111

Platform

macOS (Darwin 25.4.0), zsh, Ghostty terminal.

Additional context

• Feedback ID: 20aab3e2-5310-4d40-a6d6-4c28a867f515

• Configuration includes plugins (Mapbox, Slack), custom agents (low-dev, mid-dev, high-dev), and a number of user/plugin skills. However, the same configuration was in place for both measurements — only the CC version and model changed.
• Happy to provide full /context dumps from both versions if useful.

<img width="660" height="484" alt="Image" src="https://github.com/user-attachments/assets/2ee61e34-6ba4-4d2c-b749-57f8064284f6" />

<img width="724" height="514" alt="Image" src="https://github.com/user-attachments/assets/0e84cb3e-9c73-4750-b4f5-a19fdfd75507" />

Errors

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/dzianissheka/.local/share/claude/versions/2.1.111 (expected in multi-process scenarios)\n    at Kd_ (/$bunfs/root/src/entrypoints/cli.js:2748:2177)\n    at qe6 (/$bunfs/root/src/entrypoints/cli.js:2748:1257)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-04-16T18:20:34.729Z"},{"error":"Error: Claude Code web sessions require authentication with a Claude.ai account. API key authentication is not sufficient. Please run /login to authenticate, or check your authentication status with /status.\n    at rD (/$bunfs/root/src/entrypoints/cli.js:2628:1328)\n    at ac1 (/$bunfs/root/src/entrypoints/cli.js:3084:14570)\n    at Se9 (/$bunfs/root/src/entrypoints/cli.js:3084:15206)\n    at Iw5 (/$bunfs/root/src/entrypoints/cli.js:5452:14243)\n    at xw5 (/$bunfs/root/src/entrypoints/cli.js:5452:14320)\n    at _f (/$bunfs/root/src/entrypoints/cli.js:477:26078)\n    at useState (/$bunfs/root/src/entrypoints/cli.js:477:104955)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:467:9336)\n    at ia_ (/$bunfs/root/src/entrypoints/cli.js:5452:14280)\n    at KV7 (/$bunfs/root/src/entrypoints/cli.js:6257:26313)\n    at async <anonymous> (/$bunfs/root/src/entrypoints/cli.js:18148:2451)","timestamp":"2026-04-16T18:20:34.792Z"},{"error":"Error: Claude Code web sessions require authentication with a Claude.ai account. API key authentication is not sufficient. Please run /login to authenticate, or check your authentication status with /status.\n    at rD (/$bunfs/root/src/entrypoints/cli.js:2628:1328)\n    at ac1 (/$bunfs/root/src/entrypoints/cli.js:3084:14570)\n    at Se9 (/$bunfs/root/src/entrypoints/cli.js:3084:15206)\n    at Iw5 (/$bunfs/root/src/entrypoints/cli.js:5452:14243)\n    at xw5 (/$bunfs/root/src/entrypoints/cli.js:5452:14320)\n    at _f (/$bunfs/root/src/entrypoints/cli.js:477:26078)\n    at useState (/$bunfs/root/src/entrypoints/cli.js:477:104955)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:467:9336)\n    at ia_ (/$bunfs/root/src/entrypoints/cli.js:5452:14280)\n    at ay7 (/$bunfs/root/src/entrypoints/cli.js:6257:18467)\n    at async <anonymous> (/$bunfs/root/src/entrypoints/cli.js:18148:2451)","timestamp":"2026-04-16T18:20:34.792Z"}]