[BUG] Session usage increasing without active prompts — macOS, Cowork/Chat/Code

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?

Summary

Session usage increases during confirmed idle periods — no Chat, Cowork, or Code sessions open or active. This has occurred twice within 24 hours, with precise timestamps documented below.

Incident 1 — June 10, 2026

• At approximately 19:00 MDT, all Claude activity stopped. Session usage: 84%.
• - No Chat, Cowork, or Code sessions were open or running after that time.
• - - At approximately 21:10 MDT (~2 hours 10 minutes later), session usage had jumped to 100%.
• - - - Net unexplained consumption: ~16 percentage points with zero user-initiated activity.

Incident 2 — June 11, 2026

• Completed a Claude Code session at approximately 08:00 MDT. Session usage: 19%.
• - No Chat, Cowork, or Code sessions were open or running after that time.
• - - By approximately 10:00 MDT, session usage had climbed to 64%.
• - - - Net unexplained consumption: ~45 percentage points with zero user-initiated activity.

What I ruled out

• I have one enabled scheduled task (a daily SITREP brief, weekdays at ~15:39 MDT). It was not running during either incident window.
• - No other scheduled tasks, background agents, skills, bots, or automations were active.
• - - A Gmail MCP connector is connected but was not being invoked.
• - - - Anthropic email support (support@anthropic.com) was contacted but the response was unhelpful.

Related issues (pattern is ongoing and cross-platform)

• #53378 — [BUG] Claude Code usage increasing without active prompts (closed as not planned/stale)
• - #38029 — [BUG] Abnormal Usage Consumption on Claude Code Session Resume
• - - #37436 — [BUG] MAX100 subscription - abnormal quota consumption with multi-session Claude Code

This report adds a macOS/Cowork/Chat/Code surface to an already-documented pattern. The behavior persists as of June 2026.

What Should Happen?

Session usage should only increase when the user actively sends prompts or executes commands. During confirmed idle periods — no open sessions, no background tasks, no automations — usage should remain static. Token consumption without corresponding user activity should never occur.

Error Messages/Logs

No explicit error messages or logs. Usage metrics increase silently with no visible API calls, no CLI output, and no corresponding activity in any Claude surface.

Steps to Reproduce

1. Complete all Claude activity (Chat, Cowork, Code) and note the session usage percentage.
2. 2. Close all Claude sessions. Confirm no scheduled tasks, agents, or automations are running.
3. 3. Wait 1–3 hours without opening any Claude surface.
4. 4. Return and check session usage.
5. 5. Observe that usage has increased despite zero user activity.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Latest (claude.ai — Cowork, Chat, and Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Note: This issue is observed on claude.ai (Cowork, Chat, and Code surfaces) on macOS — not via direct API integration. The Platform field above does not have a claude.ai option; "Anthropic API" is the closest available selection.

Email support at support@anthropic.com was contacted prior to filing this issue. The response was an automated AI reply that did not address the substance of the report.