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Matins
23 changes / 4 actionable / 2 deep dives
Claude Code
  • fallbackModel in settings.json stacks up to three fallback models tried in order when the primary is overloaded or unavailable. --fallback-model now 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.
  • SendMessage across 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 fallbackModel setting to configure up to three fallback models tried in order when the primary model is overloaded or unavailable; --fallback-model now 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 SendMessage from 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 update now announces the target version before downloading instead of going silent
  • claude 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-host processes spinning at 100% CPU after the daemon dies while connected on macOS
  • Fixed voice mode requiring /login to 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/deniedMcpServers predicates 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 /doctor showing 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 agents dispatch 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.