Quick Jump

• 2.1.x Series (January-August 2026): /skill-doctor unused-skill audit + bashOutputMaxChars/taskOutputMaxChars limits + resumed-session hook-output fix (2.1.261), ⭐ /diff panel for live uncommitted-change review + parenthesis/regex permission-rule security fixes + Fable [1m] tag fix (2.1.260), ⭐ managedMcpServers org-wide MCP setting + --permission-prompts none + concurrent-session ~/.claude.json corruption fix + Bash Read() deny-rule gap closures (2.1.259), macOS 12 launch regression fix + remote/scheduled session empty-content fix (2.1.258), ⭐ Claude Fable 5.1 becomes the default Fable model (1M context) + Containment Escape auto-mode rule + permissions.blockReadsOutsideWorkingDirectories + project-level bypassPermissions now ignored (2.1.257), bug fixes: task-output-swap error on Mac + "always allow" save fix + Remote Control stall fix (2.1.252), ⭐ PreModelSwitch/PostModelSwitch hooks + /usage spend-limit bar + symlink/plugin-path/sandbox-output security fixes + CLAUDE_CODE_SUBAGENT_MODEL now a default not an override (2.1.251), bug fixes (2.1.250), ⭐ --restricted mode removing command/code/WebFetch tools + Bedrock/Vertex/Foundry cross-session messaging + hourly prompt-cache-miss fix + per-agent experimental.cacheTtl (2.1.248), SendFeedback tool + Sonnet 5 full 1M-context auto-compact window + /claude-api cost-optimize + sub-agent model-404 fallback fix (2.1.247), Bash allow-rule wildcard startup warning + Auto mode tab in /permissions + Write tool overwrite-freeze fix + non-interactive session auto-continue on stream cutoff (2.1.246), glibc 2.44 startup crash fix on Linux (2.1.245), /usage Loops breakdown + modelPicker setting + promptCacheTtl/subagentPromptCacheTtl settings + keyless Anthropic Console sign-in (2.1.243), bug fixes (2.1.241, 2.1.240), ⭐ Bedrock streaming proxy fix that stopped billing every turn twice + Windows cross-session SendMessage/ListAgents + data-residency cost premium in /cost + claude-api upgrade for the Python SDK (2.1.239), keybindingFlavor: "readline" + plugin marketplace headersHelper + long-session memory-growth fix + self-hosted-runner graceful shutdown and proxy auth headers (2.1.238), built-in "Concise" output style + gateway prompt-caching fix (2.1.237), ANTHROPIC_DEFAULT_MODEL + notify_when_idle on cross-session SendMessage + macOS sandbox wildcard read-deny precedence + auto-mode classifier parity on Bedrock/Vertex/Foundry (2.1.236), prompt-input spellcheck setting + permission dialogs matching what a grant covers + lighter background cloud sessions (2.1.235), ⭐ NT-namespace (\??\) path rejection across every pre-approval file access + GitLab MR badge in footer/statusline + auto-continue when a claude.ai usage limit resets + claude-api skill context cost cut from ~200K to ~25K tokens (2.1.234), todo/task tools removed on Opus 4.8/Sonnet 5/Fable 5/Mythos 5 and newer + CLAUDE_CODE_TOOL_MEMORY_LIMIT memory cgroups on Linux + NT \??\ UNC-validation bypass fixed + 2.1.232 Bash permission changes reverted (2.1.233), ⭐ subagent forking on by default + @-mention another session by name + GitLab plugin marketplaces and token redaction + PowerShell/Git Bash/nested-repo-trust security fixes (2.1.232), MCP OAuth redirect URI fix for pre-registered clients (2.1.231), plugin marketplace command sources + streaming duplication fix + narrow-terminal and Windows-path crash fixes + /commit-push-pr dangerous-flag approvals + VSCode session groups (2.1.229), claude.ai-synced skill hardening + Write tool overwrite rule for newer models + memory-folder cleanup fix (2.1.228), Fable usage-credits prompt fix for Max + claude-code-action Bash fix (2.1.227), bug fixes (2.1.226), gateway spend-limit warning + SendMessage to Remote Control sessions on other machines + CLAUDE_CODE_OAUTH_TOKEN 401 fix (2.1.225), ⭐ self-hosted environments (claude self-hosted-runner) + cross-session SendMessage + archive plugin source + sandbox credential masking + 200-subagent cap removed (2.1.224), ⭐ security fixes for Bash/PowerShell permission-check bypasses (hidden command parts, tab/Unicode padding, workflow-script sandbox escape via dynamic import()) + /review becomes a /code-review alias + owner wildcard marketplace entries + /teleport hint (2.1.223), ⭐ security fix for worktree-isolated sessions running destructive git commands against the main checkout + PreToolUse auto-allow bypass fix + Remote Control auto-start locked to user scope + ultraplan removed (2.1.222), ⭐ security fixes for a Bash zsh [[ ]] permission bypass and a PowerShell path-quoting bypass + VSCode Focus view + sandbox credential masking + background sessions auto commit/push (2.1.221), bug fixes (2.1.220), ⭐ Claude Opus 5 becomes the default Opus model with 1M context and fast mode at $10/$50 per Mtok + DirectoryAdded hook + sandbox.network.strictAllowlist + workflowSizeGuideline setting + subagent nesting restored to depth 3 + Opus 4.7 dropped from fast mode (2.1.219), ⭐ /code-review runs as a background subagent + agent frontmatter hooks require workspace trust + context: fork skills background by default + /deep-research manual-only + left-arrow conversation-discard fix (2.1.218), concurrent subagent cap (default 20) + --max-budget-usd halts background subagents + MCP truncated-output memory leak fix + emoji shortcode autocomplete + background-session symlink escape fix (2.1.217), sandbox.filesystem.disabled + quadratic message-normalization slowdown fix + auto-mode HTTP 401 classifier fix (2.1.216), /verify and /code-review skills no longer auto-invoked (2.1.215), ⭐ eight Bash permission-check security fixes + EndConversation tool + long-tool-call heartbeat + OTel message correlation attributes + hook dir/** matching narrowed to cwd (2.1.214), ⭐ /fork copies conversation into a background session + in-session subagent renamed /subtask + WebSearch/subagent-spawn session caps + MCP calls auto-background after 2min + plan-mode Bash permission-prompt security fix + Task tool mode param deprecated (2.1.212), --forward-subagent-text + permission-preview character-neutralization security fix + auto-mode PreToolUse ask floor + subagent model-override resume fix (2.1.211), live elapsed-time counter on tool calls + Agent tool prompt-injection hardening + Write(path)/Glob(path) permission rules deprecated (2.1.210), background-session dialog fix (2.1.209), ⭐ screen reader mode + vimInsertModeRemaps + CLAUDE_CODE_PROCESS_WRAPPER (2.1.208), ⭐ Bedrock/Vertex/AWS default to Opus 4.8 + terminal streaming perf fix + plugin shell-injection hardening (2.1.207), /doctor full setup checkup + /commit-push-pr push-remote auto-allow + background agents upgrade after update (2.1.206), ⭐ /doctor becomes full setup checkup (/checkup alias) + agent view classifier headlines + auto mode blocks transcript tampering (2.1.205), SessionStart hook streaming fix in headless sessions (2.1.204), login-expiry warning + manual-mode footer badge + background-agent stability fixes (2.1.203), dynamic workflow size setting + workflow OTel attributes (2.1.202), Sonnet 5 harness reminder role fix (2.1.201), ⭐ permission mode 'default' renamed 'Manual' + AskUserQuestion no longer auto-continues (2.1.200), retry hardening + subagent partial-work fixes + stacked slash-skill loading (2.1.199), ⭐ subagents background by default + Claude in Chrome GA (2.1.198), ⭐ Claude Sonnet 5 default model + native 1M context (2.1.197), org default models + clickable file attachments + security fix for self-approved .mcp.json servers (2.1.196), bug fixes: hook exact-match + voice dictation + background agents (2.1.195), ⭐ OTel response event + autoMode.classifyAllShell + bash path autocomplete (2.1.193), ⭐ /rewind after /clear + ~37% CPU streaming reduction + MCP reliability improvements (2.1.191), bug fixes (2.1.190), ⭐ sandbox.credentials + org model restrictions + MCP 5-min timeout (2.1.187), ⭐ claude mcp login/logout + ! bash auto-response + background subagent permission prompts (2.1.186), stream-stall hint improved to 20s delay (2.1.185), ⭐ auto mode safety blocks destructive git/terraform ops (2.1.183), ⭐ /config key=value inline setting syntax + subagent panel improvements + 30+ bug fixes (2.1.181), bug fixes: connection drops + WSL2 scroll (2.1.179), ⭐ Tool(param:value) permission syntax + nested skills + auto mode classifier (2.1.178), ⭐ session titles in conversation language + enforceAvailableModels (2.1.176, 2.1.175), wheelScrollAccelerationEnabled + VS Code usage attribution (2.1.174), bug fixes (2.1.173), ⭐ sub-agents spawn sub-agents + Bedrock region auto-detection (2.1.172), ⭐ Claude Fable 5 (2.1.170), ⭐ --safe-mode + /cd command (2.1.169), bug fixes (2.1.168, 2.1.167, 2.1.165), fallbackModel + deny rule glob + thinking disable + hardened SendMessage (2.1.166), requiredMinimumVersion/requiredMaximumVersion + /plugin list + Stop hook additionalContext (2.1.163), Quieter startup + agents waitingFor + slash-command fill-in (2.1.162), OTEL custom dimensions + agents done/total + parallel tool-call isolation (2.1.161), ultracode keyword replaces workflow + security prompts for startup files + Edit after grep (2.1.160), internal infra (2.1.159), Auto mode on Bedrock/Vertex/Foundry for Opus 4.7/4.8 (2.1.158), plugin auto-load from .claude/skills + claude plugin init + 20+ bug fixes (2.1.157), Opus 4.8 thinking-blocks crash fix (2.1.156), Opus 4.8 + dynamic workflows + lean system prompt default (2.1.154), /model saves as default (IDE parity) + modelPicker keybinding rename (2.1.153), code-review fix applies to working tree, disallowed-tools frontmatter, MessageDisplay hook, auto mode opt-in removed, 35+ bug fixes (2.1.152), internal infra (2.1.150), /usage per-category breakdown (skills/subagents/plugins/MCP), GFM task list checkboxes, PowerShell permission bypass security fix, sandbox worktree write allowlist fix, allowAllClaudeAiMcps enterprise setting, 20+ bug fixes, pinned background sessions (Ctrl+T), /code-review --comment for inline GitHub PR comments, auto-updater improvements, Bash exit-127 hotfix, /code-review command (renamed from /simplify) with effort level, AskUserQuestion restored in auto mode, agents --json, /plugin previews before install, permission-prompt bypass security fix, /resume lists background sessions, /model session-only (d for default), usage credits rename, 75s startup hang fix, plugin dependency enforcement, projected context cost in /plugin, worktree.bgIsolation: "none", fast mode Opus 4.7 default, new claude agents dispatch flags, SKILL.md root-level plugin surfacing, hook terminalSequence, claude agents --cwd, Rewind summarize, subagent_type case-insensitive, plugin folder warnings, agent view (Research Preview), /goal command, hook args exec form + continueOnBlock, settings.autoMode.hard_deny, CLAUDE_CODE_ENABLE_FEEDBACK_SURVEY_FOR_OTEL, MCP /clear disappear fix, 40+ UI fixes, worktree.baseRef setting, effort level in hooks, CLAUDE_CODE_SESSION_ID in Bash env, CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN, MCP memory fix (10GB+ RSS), subagent skills fix, 40+ bug fixes, Worktree isolation, background agents, ConfigChange hook, Fast mode Opus 4.6, 1M context, claude.ai MCP connectors, remote-control, auto-memory, /copy command, HTTP hooks, worktree config sharing, ultrathink re-introduced, InstructionsLoaded hook, 4 security fixes, Agent model override restored, 12x SDK token cost reduction, /context actionable suggestions, modelOverrides setting, 1M context Opus 4.6 default for Max/Team/Enterprise, MCP elicitation, PostCompact hook, /effort command, Opus 4.6 64k/128k output tokens, allowRead sandbox setting, /branch command, StopFailure hook, streaming line-by-line, --console auth flag, SessionEnd fix, enterprise retry fix, rate_limits statusline field, effort frontmatter for skills, --channels MCP research preview, --bare flag, worktree session resume fix, MCP query collapsing, managed-settings.d/ drop-in, CwdChanged/FileChanged hooks, transcript search, credential scrubbing, PowerShell tool Windows preview, conditional hooks if field, MCP headersHelper multi-server env vars, headless AskUserQuestion hooks, X-Claude-Code-Session-Id header, Jujutsu/Sapling VCS exclusions, @ mention token reduction, Read tool compact format, Cowork Dispatch fix, PermissionDenied hook, thinking summaries off by default, "defer" PreToolUse permission, CLAUDE_CODE_NO_FLICKER, /powerup interactive lessons, PowerShell hardened permissions, SSE linear-time performance, MCP 500K result override, disableSkillShellExecution, plugin bin/ executables, Edit tool shorter anchors, interactive Bedrock wizard, forceRemoteSettingsRefresh, /cost per-model breakdown, interactive /release-notes, Linux sandbox apply-seccomp fix, Bedrock Mantle support, high effort default for API/enterprise users, Bedrock auth fix, NO_FLICKER focus view (Ctrl+O), refreshInterval status line, 30+ bug fixes, Vertex AI wizard, Monitor tool, CLAUDE_CODE_PERFORCE_MODE, Bash security hardening, subprocess PID namespace sandboxing, /team-onboarding command, OS CA cert store trust by default, /ultraplan auto-cloud-environment, 40+ bug fixes, PreCompact hook blocking, EnterWorktree path param, plugin monitors, /proactive alias, WebFetch CSS/JS stripping, /doctor status icons, thinking hints sooner, ENABLE_PROMPT_CACHING_1H, /recap session context, built-in slash commands via Skill tool, /undo alias, rotating extended-thinking indicator, /tui fullscreen command, push notification tool, --resume resurrects scheduled tasks, /focus command, autoScrollEnabled config, session recap for telemetry-disabled, 30+ bug fixes, Opus 4.7 xhigh effort, /ultrareview cloud code review, /less-permission-prompts skill, Auto mode for Max subscribers, plan files named after prompts, read-only bash glob patterns no prompt, interactive /effort slider, many bug fixes, native binary spawning, sandbox.network.deniedDomains, security hardening exec wrappers, crash fix permission dialog, /resume 67% faster, inline thinking progress, sandbox dangerous-path security fix, agent frontmatter hooks via --agent, many terminal and UI bug fixes, default effort high for Pro/Max on Opus 4.6+Sonnet 4.6, native bfs/ugrep on macOS/Linux, /model persistence across restarts, Opus 4.7 1M context fix, 15+ bug fixes, vim visual mode, /usage merged from /cost+/stats, custom named themes, hooks invoke MCP tools, DISABLE_UPDATES env var, wslInheritsWindowsSettings, 15+ bug fixes, /config settings persist to settings.json, --from-pr multi-platform support, agent frontmatter honors tools+permissionMode, blockedMarketplaces security fix, TaskList ordering fix, 30+ bug fixes, Windows no longer requires Git Bash (PowerShell fallback), claude ultrareview CI subcommand, ${CLAUDE_EFFORT} in skills, alwaysLoad MCP option, plugin prune, PostToolUse output replacement for all tools, ANTHROPIC_BEDROCK_SERVICE_TIER, PR URL in /resume search, OAuth 401 hotfix, gateway /v1/models listing in /model picker, claude project purge, OAuth paste code for WSL2/SSH/containers, security fix allowManagedDomainsOnly/allowManagedReadPathsOnly, Windows PowerShell 7 as primary shell, 40+ bug fixes, EnterWorktree branch from local HEAD fix, --plugin-dir .zip support, --channels console auth, /mcp tool count per server, parallel bash tool call fix, sub-agent prompt cache fix, 35+ bug fixes, --plugin-url flag, CLAUDE_CODE_PACKAGE_MANAGER_AUTO_UPDATE, Ctrl+R all-projects history restored, skillOverrides fix, 1h cache TTL fix, OAuth refresh race fix, 20+ bug fixes, VS Code Windows activation fix, Mantle auth fix
• 2.0.x Series (Nov 2025 - Jan 2026): Opus 4.5, Claude in Chrome, Background agents
• Breaking Changes Summary
• Milestone Features