5Claude Code Release Notes·
Claude Code 2.1.212 release: /fork background sessions, runaway-loop caps, and ~40 bug fixes
Anthropic shipped Claude Code version 2.1.212 with several notable behavioral changes: /fork now copies conversations into independent background sessions (previously launched in-session subagents), and new per-session caps on WebSearch calls (default 200) and subagent spawns (default 200) guard against runaway loops. MCP tool calls exceeding 2 minutes are automatically backgrounded to keep sessions responsive. The release also includes roughly 40 bug fixes spanning plan-mode permission bypasses, SIGTERM process-tree orphaning, Windows PowerShell compatibility, /ultrareview edge cases, OpenTelemetry export failures, and prompt caching improvements for LLM gateways.
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Claude Code 2.1.216 release: quadratic slowdown fix, agent session restoration, and broad bug fixes
Anthropic released Claude Code version 2.1.216, a maintenance update addressing a significant performance regression where message normalization cost grew quadratically with conversation length, causing multi-second stalls in long sessions. The release also fixes agent session state restoration (prompt and tool restrictions now persist across resumes), OAuth token expiry mid-session, and numerous edge cases in worktree isolation, background subagent lifecycle, and MCP re-authentication. Additional improvements cover UI rendering, telemetry accuracy, PowerShell/Bash command parsing, and cloud session resilience on container restart.
Claude Code 2.1.203 release: major background agent reliability fixes and MCP roots integration
Anthropic released Claude Code version 2.1.203, a substantial patch addressing over 25 bugs primarily affecting background agent sessions, subagent orchestration, and worktree isolation. Key fixes include automatic recovery when daemon session tokens go stale, correct subagent state carry-over when returning to sessions, and PATH/environment variable inheritance issues on Windows. The release also adds MCP roots/list integration for working directories and improves streaming responsiveness.
Claude Code 2.1.210 release: bug fixes, security hardening, and agent workflow improvements
Anthropic released Claude Code version 2.1.210, a substantial patch addressing over 30 bugs and adding several improvements to the agentic coding tool. Notable fixes include hardening against indirect prompt injection via subagent-read content, correcting git worktree isolation for subagents, fixing hook callback timeouts that caused unattended sessions to stall, and resolving MCP server teardown during mid-session re-syncs. The release also improves auto-mode permission classification by defaulting to Sonnet 5 for external sessions and adds UX enhancements for the multi-agent dashboard.
Claude Code 2.1.214 release: security fixes, EndConversation tool, and extensive bug fixes
Anthropic released Claude Code version 2.1.214, a substantial patch addressing multiple permission-check security vulnerabilities including a Windows PowerShell 5.1 bypass, file-descriptor redirect bypass, and path-traversal issues in allow rules. The release adds the EndConversation tool enabling Claude to terminate sessions with abusive users or jailbreak attempts, improved OpenTelemetry observability attributes, and docker/Podman permission prompts. Dozens of bug fixes address Windows-specific issues, background session lifecycle problems, memory management, and streaming reliability.
Claude Code 2.1.191 release: /rewind support, MCP reliability improvements, 37% CPU reduction
Anthropic shipped Claude Code version 2.1.191 with a notable set of bug fixes and performance improvements. Key additions include /rewind support for resuming conversations before a /clear, roughly 37% CPU reduction during streaming via coalesced text updates, and improved MCP server reliability with retry logic for transient network errors. Several agent-related bugs were fixed, including background agents resurrecting after being stopped and slash commands being incorrectly forwarded to background sessions.
Claude Code 2.1.208 release: accessibility, background agents, memory fixes, and performance improvements
Anthropic released Claude Code version 2.1.208, a substantial patch addressing dozens of bugs and adding several new features. Key additions include screen reader accessibility mode, vim insert-mode remapping, and a corporate process wrapper for enterprise deployments. The release fixes significant issues including memory leaks in long sessions, background agent reliability problems, streaming output truncation, and multi-second per-turn slowdowns from permission rule matching, alongside performance improvements yielding up to 7x faster tool rounds at high MCP tool counts.
Claude Code 2.1.196 release: org-default models, MCP security fix, background agent reliability improvements
Anthropic released Claude Code version 2.1.196 with a notable security fix preventing untrusted workspace .mcp.json servers from auto-spawning, and added support for organization-level default model configuration via the admin console. The release includes significant background agent reliability improvements — long-running workflows now survive process restarts on all platforms including Windows — plus a streaming idle watchdog enabled by default that aborts and retries stalled response streams after 5 minutes. Numerous bug fixes address agent session state management, MCP OAuth scope handling, PowerShell compatibility, and a /code-review token usage reduction of ~25%.
Claude Code 2.1.211 release: subagent streaming, security hardening, and numerous bug fixes
Anthropic released Claude Code version 2.1.211 with a new --forward-subagent-text flag to expose subagent thinking in stream-json output, and a significant security fix neutralizing bidirectional-override and zero-width characters in permission previews that could visually alter approval messages. The release also fixes a prompt-caching regression on Bedrock, Vertex, Mantle, and Foundry that was incorrectly billing trailing system context blocks as fresh input tokens on every request. Dozens of additional bug fixes address session management, background agent lifecycle, Windows compatibility, MCP reconnection, and rendering performance.