# Claude Code 2.1.49

Captured: 2026-05-10T16:27:28.327Z

- Improved MCP OAuth authentication with step-up auth support and discovery caching, reducing redundant network requests during server connections
- Added `--worktree` (`-w`) flag to start Claude in an isolated git worktree
- Subagents support `isolation: "worktree"` for working in a temporary git worktree
- Added Ctrl+F keybinding to kill background agents (two-press confirmation)
- Agent definitions support `background: true` to always run as a background task
- Plugins can ship `settings.json` for default configuration
- Fixed file-not-found errors to suggest corrected paths when the model drops the repo folder
- Fixed Ctrl+C and ESC being silently ignored when background agents are running and the main thread is idle. Pressing twice within 3 seconds now kills all background agents.
- Fixed prompt suggestion cache regression that reduced cache hit rates.
- Fixed `plugin enable` and `plugin disable` to auto-detect the correct scope when `--scope` is not specified, instead of always defaulting to user scope
- Simple mode (`CLAUDE_CODE_SIMPLE`) now includes the file edit tool in addition to the Bash tool, allowing direct file editing in simple mode.
- Permission suggestions are now populated when safety checks trigger an ask response, enabling SDK consumers to display permission options
- Sonnet 4.5 with 1M context is being removed from the Max plan in favor of our frontier Sonnet 4.6 model, which now has 1M context. Please switch in /model.
- Fixed verbose mode not updating thinking block display when toggled via `/config` — memo comparators now correctly detect verbose changes
- Fixed unbounded WASM memory growth during long sessions by periodically resetting the tree-sitter parser
- Fixed potential rendering issues caused by stale yoga layout references
- Improved performance in non-interactive mode (`-p`) by skipping unnecessary API calls during startup
- Improved performance by caching authentication failures for HTTP and SSE MCP servers, avoiding repeated connection attempts to servers requiring auth
- Fixed unbounded memory growth during long-running sessions caused by Yoga WASM linear memory never shrinking
- SDK model info now includes `supportsEffort`, `supportedEffortLevels`, and `supportsAdaptiveThinking` fields so consumers can discover model capabilities.
- Added `ConfigChange` hook event that fires when configuration files change during a session, enabling enterprise security auditing and optional blocking of settings changes.
- Improved startup performance by caching MCP auth failures to avoid redundant connection attempts
- Improved startup performance by reducing HTTP calls for analytics token counting
- Improved startup performance by batching MCP tool token counting into a single API call
- Fixed `disableAllHooks` setting to respect managed settings hierarchy — non-managed settings can no longer disable managed hooks set by policy (#26637)
- Fixed `--resume` session picker showing raw XML tags for sessions that start with commands like `/clear`. Now correctly falls through to the session ID fallback.
- Improved permission prompts for path safety and working directory blocks to show the reason for the restriction instead of a bare prompt with no context
