[Bug] Intermittent malformed tool-call emission with corrupted "court" prefix delimiter

Bug Description
Intermittent malformed tool-call emission — spurious court + <invoke> prefix stalls the turn. Intermittently a tool call is emitted with a corrupted opening delimiter: a literal court prefix followed by an XML-style <invoke name="..."> tag, instead of the real function-call token. The harness doesn't parse it — it prints the block as plain text and the turn stalls (no tool runs). The user must nudge; re-emitting the byte-identical call then executes fine. - Not content-dependent: same Bash/PushNotification/Monitor call, re-emitted, works. - Ruled out project causes: no hooks, no env overrides in ~/.claude/settings.json. - Seen across Bash, Monitor, PushNotification in one session; ~6+ occurrences over a multi-hour run. - Impact: silently stalls autonomous/long-running loops until manual intervention. Env: Claude Code 2.1.200 · model claude-opus-4-8 (Opus 4.8, 1M) · Linux 6.17. Expected: every tool call emitted with the correct delimiter and executed deterministically.

Environment Info

• Platform: linux
• Terminal: vte-based
• Version: 2.1.197
• Feedback ID: 298cf213-a292-42f1-9ba8-12e1a615e3e7

Errors

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