Tool calls silently fail / return empty mid-session

Environment

• OS: Fedora 43 (Gram17-fedora laptop, GNOME Wayland)
• Model: claude-opus-4-6[1m]
• Claude Code: latest as of 2026-04-14

Symptom

Bash tool calls mid-session either:

1. Return Tool result missing due to internal error, OR
2. Hang indefinitely with no output returned to the model

Failure is intermittent within the same session — some calls succeed, others silently fail. Once degradation begins, the session becomes unusable as the model cannot observe command results.

Impact

From the user's perspective the assistant appears to freeze or loop. From the model's perspective, tool results are missing so it cannot make progress or diagnose. Creates long frustrating back-and-forth where neither side can tell what's broken.

Repro

Unclear root cause. Degradation appeared mid-session after ~dozen successful tool calls. No obvious trigger (no large outputs, no special characters, no long-running commands at the point of failure).

Expected

Tool calls should either succeed with output, or return a structured error the model can recognize and recover from.

Workaround

Restart the Claude Code session (exit + claude again).

Logs

~/.claude/logs/ on the affected machine.