Claude Code 2.1.277 adds AGENTS.md fallback support, new gateway proxy options, and fixes CLI session hangs

Claude Code 2.1.277 now reads AGENTS.md when a project lacks CLAUDE.md, with the setting configurable under Project instructions in /config. The release also adds gateway proxy controls and fixes several reliability issues, including hung CLI and Agent SDK sessions, resume failures tied to empty text blocks, unexpected logouts, update-check errors, and plugin reinstall problems.

The AGENTS.md fallback reflects a broader push toward more portable, tool-agnostic project instruction files as AI coding agents proliferate. The proxy and gateway changes also show Anthropic adapting Claude Code for more controlled enterprise deployments, where network boundaries, static headers, and predictable failure modes matter as much as model capability.