fallbackModelinsettings.jsonstacks up to three fallback models tried in order when the primary is overloaded or unavailable.--fallback-modelnow applies to interactive sessions too, not just headless and pipe mode. (more below)- Deny rules now accept glob patterns in the tool-name position, including
"*"to deny all tools. Allow rules reject non-MCP globs, and unknown tool names in deny rules warn at startup, so check your config if you see new warnings. SendMessageacross sessions no longer carries user authority. Receivers refuse relayed permission requests, and auto mode blocks them, so multi-session permission-relay workflows will break. (more below)MAX_THINKING_TOKENS=0,--thinking disabled, and the per-model thinking toggle now actually disable thinking on default-thinking models via the Claude API. Third-party providers are unchanged.
New in 2.1.167, 2.1.166, 2.1.165
2.1.167 (June 6, 2026)
- Bug fixes and reliability improvements
2.1.166 (June 6, 2026)
- Added
fallbackModelsetting to configure up to three fallback models tried in order when the primary model is overloaded or unavailable;--fallback-modelnow also applies to interactive sessions - Added glob pattern support in deny rule tool-name position (
"*"denies all tools); allow rules reject non-MCP globs, and unknown tool names in deny rules warn at startup - Hardened cross-session messaging: messages relayed via
SendMessagefrom other Claude sessions no longer carry user authority, receivers refuse relayed permission requests, and auto mode blocks them MAX_THINKING_TOKENS=0,--thinking disabled, and the per-model thinking toggle now disable thinking on models that think by default via the Claude API (3P providers unchanged)- Claude Code now retries a turn once on the fallback model when the API rejects an unexpected non-retryable error; auth, rate-limit, request-size, and transport errors still surface immediately
claude updatenow announces the target version before downloading instead of going silentclaude agents: typing a URL into the list now filters to the session whose first prompt contained it- Fixed a recurring "image could not be processed" error and extra token usage when an unprocessable image was sent in a session
- Fixed remote sessions becoming permanently stuck when a brief backend disruption occurred during worker registration at startup
- Fixed flickering in JetBrains IDE terminals (IntelliJ, PyCharm, WebStorm, etc.) on 2026.1+ by enabling synchronized output
- Fixed Shift+non-ASCII characters (e.g. Shift+ä → Ä) being dropped in terminals using the Kitty keyboard protocol (WezTerm, Ghostty, kitty)
- Fixed PowerShell command validation occasionally hanging far past its time budget on Windows when a killed process's children held its output pipes
- Fixed orphaned
claude --bg-pty-hostprocesses spinning at 100% CPU after the daemon dies while connected on macOS - Fixed voice mode requiring
/loginto clear a stale auth check after toggling/voice - Fixed managed settings with an invalid entry silently disabling enforcement of their remaining valid policies
- Fixed managed-settings
allowedMcpServers/deniedMcpServerspredicates not matching when they use${VAR}references - Fixed background agent sessions that entered a git worktree crash-looping with "No conversation found" when reopened from
claude agents - Fixed duplicated thinking text in the Ctrl+O transcript view while streaming
- Fixed
/doctorshowing a contradictory failed "Not inside a remote session" check when run inside a remote session - Fixed the cursor sticking at the end of the first line when typing a multiline prompt in the
claude agentsdispatch and reply inputs - Fixed blank lines appearing between background agent rows in the task list on terminals without Unicode support
2.1.165 (June 6, 2026)
- Bug fixes and reliability improvements
Notes
fallbackModel completes a three-release arc from CLI flag to persistent setting. In 2.1.152, --fallback-model was a CLI-only flag that switched the model for the rest of the session when the primary hit overload. In 2.1.143, /bg and detach began preserving the flag so backgrounded workers degraded gracefully. Now 2.1.166 promotes it to a settings.json entry that accepts up to three models and extends to interactive sessions. If you have been passing --fallback-model on every launch, you can set it once in settings and forget it.
Cross-session messaging authority is now locked down. The 2.1.162 fix for SendMessage silently breaking with deep $TMPDIR paths suggested cross-session messaging was getting real production use. Anthropic is now tightening the trust model: a relayed message is treated as agent-generated, not user-generated, so a coordinator session can no longer relay permission grants to workers. If you orchestrate multi-session pipelines where one session approves tools on behalf of another, those flows will need rearchitecting around explicit per-session permission grants.