[BUG] React reconciler crash: No matching component was found for

Bug Description

Claude Code crashes mid-session with a React component reconciliation error. The terminal session is killed with no recovery option - all in-flight work (tool calls, agent context) is lost.

Error Output

+(c.join(" > ")+`

No matching component was found for:

 - O7 (/$bunfs/root/claude:668:20555)
 - RX (/$bunfs/root/claude:668:28704)
 - rO (/$bunfs/root/claude:668:28858)
 - M7 (/$bunfs/root/claude:668:25070)
 - <anonymous> (/$bunfs/root/claude:471:8027)
 - ER (/$bunfs/root/claude:3559:4179)
 - W_0 (/$bunfs/root/claude:6327:12557)
 - Z$T (/$bunfs/root/claude:6340:10357)
 - v1 (/$bunfs/root/claude:668:20765)
 - U6 (/$bunfs/root/claude:668:39157)

Context / Reproduction

• Session type: Heavy MCP-driven session with multiple tool calls, background agents, and hooks (startup hooks, beads workflow, private-journal, agent-mail)
• What was happening: Mid-conversation with active MCP tool calls (kite-paper-engine FastMCP server) and multiple startup hooks resolving
• MCP servers active: kite-paper-engine (FastMCP), context7, zen, XcodeBuildMCP, agent-mail, private-journal, plus others
• Hooks active: Startup hooks (episodic-memory, beads priming), pre-tool-use hooks

The crash appears to be a React fiber tree corruption during component reconciliation - the bundled React renderer can't find a component that should exist in its tree. This is consistent with state corruption from concurrent updates (multiple tool results arriving simultaneously, hook outputs, MCP responses).

Possibly Related Issues

• #20685 - React hook dependency array undefined (similar React reconciler crash)
• #22632 - Bun segfault after extended sessions
• #10021 - General Bun crashes

Environment

• Claude Code version: 2.1.33
• OS: macOS 26.1 (Sequoia, arm64, Apple M4 Pro)
• Kernel: Darwin 25.1.0
• Terminal: Standard macOS Terminal

Impact

• Session state completely lost (no graceful degradation)
• No crash report generated or option to resume
• Particularly disruptive for long sessions with accumulated context

Expected Behavior

Either:

1. The React reconciler should handle missing components gracefully (skip render, retry)
2. Or the session should save state before crashing so /resume can recover

Suggested Investigation

The /$bunfs/root/claude:668 references suggest the crash is in the Bun-bundled React renderer. The minified function names (O7, RX, rO, M7) make it hard to pinpoint, but c.join(" > ") looks like breadcrumb/component path logging before the crash — possibly in a findComponentByFiber or similar reconciler function.

Could be triggered by:

• Race condition: multiple async tool results updating React state concurrently
• Memory pressure from large context + many MCP connections
• Hook output interleaving with tool result rendering