← Claude Code changelog

Claude Code 2.1.210

This release introduces a new live elapsed-time counter for tool calls, providing immediate visual feedback on long-running operations. It also adds startup warnings for specific permission rules, enhancing security guidance. Key fixes address critical issues such as isolated subagents modifying the main repository, external editors leaking paste markers, and session failures during attach or due to malformed tool results. Further improvements enhance reliability, user experience, and security across background services, permission handling, and the agent dashboard, benefiting all users with a more robust and responsive environment.

Added

  • 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

Improved

  • 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

Changed

  • Hardened the Agent tool against indirect prompt injection via content a subagent read
  • 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

Fixed

  • 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
  • Fable temporarily shows as unavailable in the advisor picker while a server-side issue causing Fable advisor failures is fixed