Intermittent 8-15 minute delays on simple tool calls (Write, Bash) in long sessions

Description

During a long Claude Code session (~10+ hours, 3000+ turns, ~420K tokens context on claude-opus-4-6 with 1M context), simple tool calls intermittently take 8-15 minutes to complete. This has happened approximately 20-30 times over the last 10 hours.

Reproduction

• Model: claude-opus-4-6 (1M context)
• Session: ~3,072 turns, ~418K tokens context, ~429K tokens total output
• Platform: macOS Darwin 25.2.0, Apple Silicon
• Claude Code version: latest CLI

Behavior

• A simple Write tool call (writing a small JSON file) or Bash call (a curl command) will hang for 8-15 minutes before completing
• The next response after the slow tool call is often instant (text response)
• This rules out context size as the sole cause, since the text response uses the same context
• The delays are intermittent — most tool calls complete in seconds, but some randomly stall

Expected behavior

Tool calls should complete within a few seconds, consistent with the speed of text responses at the same context size.

Environment

macOS Darwin 25.2.0
Claude Code CLI (latest)
Model: claude-opus-4-6 (1M context)
Session stats: 3072 turns, 418K context tokens

Additional context

The session involved heavy use of Bash, Write, Edit, Read, Grep, and MCP tools (Chrome automation, Slack, ClickUp). The slowness affects basic CLI tools (Write, Bash) not just MCP tools.