[BUG] MAX100 subscription - abnormal quota consumption and rate_limit_error with multi-session Claude Code

Description

MAX100 subscriber experiencing abnormal 5-hour quota consumption and rate_limit_error when running multiple Claude Code sessions simultaneously.

Environment

• Plan: Claude MAX100
• Claude Code version: 2.1.81
• OS: Windows 11 Pro
• Sessions: 5 concurrent Claude Code sessions (VS Code terminals)

Issue 1: Abnormal Quota Consumption

• Previous 5-hour quota period: 45% consumed in 45 minutes
• Current 5-hour quota period: 23% → 32% within minutes of starting sessions, with NO active work being done
• Sessions were idle (no prompts submitted, no tool calls)

Issue 2: Rate Limit Error on /usage

Error: Failed to load usage data: 
{"error":{"type":"rate_limit_error","message":"Rate limited. Please try again later."}}

This occurred immediately after session startup, with no active work.

Expected Behavior

• Idle sessions should not consume significant quota
• 5 concurrent sessions should be supported for MAX100 plan
• /usage should not return rate_limit_error

Steps to Reproduce

1. Open 5 Claude Code sessions in VS Code (different project directories)
2. Run /start-agent-chat-loop in each (registers agent + starts background watcher)
3. Observe quota rapidly increasing without any work
4. Run /usage → rate_limit_error

Additional Context

• Each session has MCP servers (agent-chat, memory, supabase, context7)
• Background watcher (watch.py) polls SQLite locally, not API
• This pattern worked fine in previous quota periods with similar setup