[Bug] Context limit calculation inaccurate: reports available tokens but hits limit prematurely

Bug Description
In this latest version, I believe the context is buggy. I if I do manually slash context, it tells me that I still have about 40,000 tokens free. Yet I already get context limit reached. I have auto compact turned off. And so if I do slash context, it says I have this many tokens free and I should be able to continue. Yet I am not able to continue because it tells me that the context limit has been reached and also in the bottom right it tells me that I have three percent context remaining and even though with three percent I'm already getting context limit reached. So something is buggy in the context thing here.

Environment Info

• Platform: darwin
• Terminal: cursor
• Version: 2.1.12
• Feedback ID: 17e82fec-fed1-4f54-8d04-f859ed2acc46

Errors

[{"error":"Error: Tool mcp__exa__web_search_exa not found\n    at SqB (/$bunfs/root/claude:2563:6640)\n    at Pq (/$bunfs/root/claude:524:20763)\n    at cC (/$bunfs/root/claude:524:39155)\n    at fm (/$bunfs/root/claude:524:49774)\n    at yM (/$bunfs/root/claude:524:86045)\n    at Js (/$bunfs/root/claude:524:85019)\n    at xm (/$bunfs/root/claude:524:84844)\n    at km (/$bunfs/root/claude:524:81267)\n    at BA (/$bunfs/root/claude:524:6274)\n    at ZsR (/$bunfs/root/claude:517:15348)","timestamp":"2026-01-20T09:48:00.377Z"},{"error":"Error: Tool mcp__exa__web_search_exa not found\n    at SqB (/$bunfs/root/claude:2563:6640)\n    at Pq (/$bunfs/root/claude:524:20763)\n    at cC (/$bunfs/root/claude:524:39155)\n    at fm (/$bunfs/root/claude:524:49774)\n    at yM (/$bunfs/root/claude:524:86045)\n    at Js (/$bunfs/root/claude:524:85019)\n    at xm (/$bunfs/root/claude:524:84844)\n    at km (/$bunfs/root/claude:524:81267)\n    at RA (/$bunfs/root/claude:524:6394)\n    at oT (/$bunfs/root/claude:524:4896)","timestamp":"2026-01-20T09:48:01.015Z"},{"error":"Error: Tool mcp__exa__web_search_exa not found\n    at SqB (/$bunfs/root/claude:2563:6640)\n    at Pq (/$bunfs/root/claude:524:20763)\n    at cC (/$bunfs/root/claude:524:39155)\n    at fm (/$bunfs/root/claude:524:49774)\n    at yM (/$bunfs/root/claude:524:86045)\n    at Js (/$bunfs/root/claude:524:85019)\n    at xm (/$bunfs/root/claude:524:84844)\n    at km (/$bunfs/root/claude:524:81267)\n    at BA (/$bunfs/root/claude:524:6274)\n    at ZsR (/$bunfs/root/claude:517:15348)","timestamp":"2026-01-20T09:48:01.133Z"},{"error":"Error: Tool mcp__exa__web_search_exa not found\n    at SqB (/$bunfs/root/claude:2563:6640)\n    at Pq (/$bunfs/root/claude:524:20763)\n    at cC (/$bunfs/root/claude:524:39155)\n    at fm (/$bunfs/root/claude:524:49774)\n    at yM (/$bunfs/root/claude:524:86045)\n    at Js (/$bunfs/root/claude:524:85019)\n    at xm (/$bunfs/root/claude:524:84844)\n    at km (/$bunfs/root/claude:524:81267)\n    at BA (/$bunfs/root/claude:524:6274)\n    at ZsR (/$bunfs/root/claude:517:15348)","timestamp":"2026-01-20T09:48:01.234Z"},{"error":"Error: Tool mcp__exa__web_search_exa not found\n    at SqB (/$bunfs/root/claude:2563:6640)\n    at Pq (/$bunfs/root/claude:524:20763)\n    at cC (/$bunfs/root/claude:524:39155)\n    at fm (/$bunfs/root/claude:524:49774)\n    at yM (/$bunfs/root/claude:524:86045)\n    at Js (/$bunfs/root/claude:524:85019)\n    at xm (/$bunfs/root/claude:524:84844)\n    at km (/$bunfs/root/claude:524:81267)\n    at BA (/$bunfs/root/claude:524:6274)\n    at ZsR (/$bunfs/root/claude:517:15348)","timestamp":"2026-01-20T09:48:01.348Z"},{"error":"Error: Tool mcp__exa__web_search_exa not found\n    at SqB (/$bunfs/root/claude:2563:6640)\n    at Pq (/$bunfs/root/claude:524:20763)\n    at cC (/$bunfs/root/claude:524:39155)\n    at fm (/$bunfs/root/claude:524:49774)\n    at yM (/$bunfs/root/claude:524:86045)\n    at Js (/$bunfs/root/claude:524:85019)\n    at xm (/$bunfs/root/claude:524:84844)\n    at km (/$bunfs/root/claude:524:81267)\n    at BA (/$bunfs/root/claude:524:6274)\n    at ZsR (/$bunfs/root/claude:517:15348)","timestamp":"2026-01-20T09:48:01.426Z"},{"error":"Error: Tool mcp__exa__web_search_exa not found\n    at SqB (/$bunfs/root/claude:2563:6640)\n    at Pq (/$bunfs/root/claude:524:20763)\n    at cC (/$bunfs/root/claude:524:39155)\n    at fm (/$bunfs/root/claude:524:49774)\n    at yM (/$bunfs/root/claude:524:86045)\n    at Js (/$bunfs/root/claude:524:85019)\n    at xm (/$bunfs/root/claude:524:84844)\n    at km (/$bunfs/root/claude:524:81267)\n    at BA (/$bunfs/root/claude:524:6274)\n    at ZsR (/$bunfs/root/claude:517:15348)","timestamp":"2026-01-20T09:48:01.502Z"},{"error":"Error: Tool mcp__exa__web_search_e

Note: Error logs were truncated.