Claude Code was printing MCP secrets resolved from ${VAR} placeholders into error messages
Claude Code Changelog·high signal
2.1.274 fixes MCP connection errors and the MCP login tool's description showing secrets resolved from `${VAR}` placeholders in MCP configs. If you templated API keys into `.mcp.json` expecting the indirection to keep them out of logs, any captured terminal output or shared error paste from before this build may contain the resolved value. Rotate anything that went through a `${VAR}` in an MCP config and was followed by a connection failure.