Malformed settings JSON cascades into classifier and MCP outages

In Claude Code, a single trailing comma in ~/.claude/settings.json (left behind after deleting env entries) made the whole settings file unparseable. Symptoms looked unrelated: every MCP server disconnected, and auto-mode permission classification failed repeatedly with a model-unavailable error because the classifier stayed pinned to a stale model binding from the broken env. /doctor surfaced it as invalid settings JSON; the fix was deleting one comma. If tool permission checks start failing with model-unavailable errors while allowlisted commands still run, validate settings JSON before blaming the API.