Claude Code v2.1.210 Release: Fixes Subagent Isolation, Session Crashes, and Paste Character Leaks

What's changed

• Added a live elapsed-time counter to the collapsed tool summary line so long-running tool calls visibly tick instead of looking stuck
• Added a startup warning for Write(path), NotebookEdit(path), and Glob(path) permission rules — use Edit(path) or Read(path) instead
• Fixed isolation: 'worktree' subagents being able to run git-mutating commands against the main repo checkout instead of their own isolated worktree
• Fixed the ultracode keyword opt-in firing on non-human-originated input such as webhook payloads and relayed PR comments
• Fixed a rendered text fragment leaking into crash telemetry when a UI component returned content outside a styled text element
• Fixed paste markers leaking into external editors opened from Claude Code, which could appear as stray È/É characters around pasted text
• Fixed claude attach sometimes failing with "job not found" or "agent is still starting" errors during session transitions — attach now waits for the daemon to settle, and terminal resizes during a slow attach are applied once it completes
• Fixed a session crash when a tool's result renderer returned a numeric bigint value or plain text instead of a UI element
• Fixed a hook callback timeout being misreported to the model as a user rejection, which made unattended sessions stop and wait
• Fixed Claude assuming a cd took effect after its command was moved to the background; the tool result now states the working directory is unchanged
• Fixed plugin-provided MCP servers being torn down when MCP servers are re-synced mid-session
• Fixed plan approvals without edits being labeled "(edited by user)" and overwriting the plan file with a stale snapshot
• Fixed /doctor skipping its auto-mode-default proposal on Bedrock, Vertex, and Foundry, where auto mode no longer needs an opt-in
• Fixed Grep content mode claiming "No matches found" when paginating past the end of results
• Fixed unmatched $1/$2 positional placeholders in skills and commands being silently stripped; they are now preserved verbatim
• Fixed plugin cache writes leaving temp files behind on failure and failing on locked-file renames on Windows and network filesystems
• Fixed background workers crash-looping when a client resets its connection to the background service
• Fixed claude agents --effort ultracode not reaching dispatched sessions; the value was silently dropped
• Fixed pressing ← to open the agents view dropping the task tracker when returning to the session
• Fixed the agents dashboard retaining pasted images from abandoned reply drafts after their session was deleted
• Fixed killed background sessions leaving a permanent git worktree lock behind; the periodic sweep now releases locks whose owning process is gone
• Fixed SDK MCP servers registered via an initialize control request waiting until the next turn to start connecting
• Fixed returning to the agents view from a session leaving overlapping ghost frames with CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1
• Fixed late-appearing .claude/* symlinks not being reconciled into the sandbox deny-write list
• Hardened the Agent tool against indirect prompt injection via content a subagent read
• Improved the Bash/PowerShell tool message when a command hits its timeout and is auto-backgrounded, so the model can distinguish a hang from an explicit background request
• Improved auto mode: the permission classifier now defaults to Sonnet 5 for external sessions, validated on the session's first request and pinned for the session
• Improved the bundled dataviz skill's chart color validation with perceptual OKLab color difference and recalibrated color-blindness thresholds
• Memory writes that leave a MEMORY.md index over its read limit now produce an explicit error instead of silent truncation
• Screen reader mode now announces permission mode changes aloud when cycling modes with Shift+Tab
• The agents footer hint now shows how many background agents are waiting on your input, with a brief color emphasis when the count changes
• Agent view: the session you pressed ← from stays visibly marked even after mouse hover or arrow keys move the selection
• Fable temporarily shows as unavailable in the advisor picker while a server-side issue causing Fable advisor failures is fixed