Claude Code v2.1.20 / Changelog

Keybindings Customization Skill #

What

New /keybindings skill enables full customization of keyboard shortcuts via ~/.claude/keybindings.json configuration file.

Usage

/keybindings

Details

Create custom keybindings organized by context (Global, Chat, Autocomplete, etc.)
Support for chord bindings (multi-keystroke shortcuts like ctrl+k ctrl+s)
Validation integrated into /doctor command with detailed error/warning messages
Unbind default shortcuts by setting them to null
Schema validation with JSON Schema support for editor autocomplete
Documentation at https://code.claude.com/docs/en/keybindings

Evidence

Skill registration at line 748555 (name: "keybindings-help", contains "Use when the user wants to customize keyboard shortcuts")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Debug Logging to File #

What

New --debug-file CLI flag writes debug logs to a specific file path.

Usage

claude --debug-file /path/to/debug.log
claude --debug-file=/path/to/debug.log

Details

Implicitly enables debug mode when specified
Useful for persistent debugging and troubleshooting

Evidence

Argument parser at line 2836 (if (K.startsWith("--debug-file="))) and help text at line 577087 ("--debug-file <path>")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Hard Fail Mode #

What

New --hard-fail CLI flag causes Claude Code to exit immediately on certain errors rather than attempting recovery.

Usage

claude --hard-fail

Details

Useful for CI/CD pipelines and automated testing
Ensures failures are detected rather than silently handled

Evidence

Detection at line 5582 (return process.argv.includes("--hard-fail"))

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Package Manager Ownership Detection #

What

New --who-owns integration for Alpine Linux (apk) package manager to verify file ownership.

Usage

Internal feature - automatically used when verifying Claude Code installation on Alpine Linux.

Details

Detects apk-managed installations with logging: "Detected apk installation: ..."
Also detects deb, rpm, and pacman installations
Enables better package manager integration and update guidance

Evidence

APK query at line 419998 (OP1("apk", ["info", "--who-owns", K]) and detection logs at lines 420004, 420011, 420018, 420025

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

SendMessageTool for Teammate Communication #

What

New SendMessageTool replaces previous teammate messaging implementation with clearer protocol separation.

Usage

Internal tool used by agents in swarm mode.

Details

Handles message, broadcast, request, and response types
Protocol subtypes for shutdown and plan approval workflows
Better error messages for missing parameters
Improved in-process teammate abort handling

Evidence

Tool definition at line 448126 (SendMessageTool: () => tT2) with logging prefix [SendMessageTool] at lines 448249, 448275, 448284

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Compact Conversation Keybinding #

What

New ctrl+k ctrl+k chord keybinding to trigger /compact command.

Usage

ctrl+k ctrl+k

Details

Quick access to conversation compaction
Uses the new chord keybinding system
Replaces removed ctrl+k ctrl+c for /commit

Evidence

Keybinding definition at line 486662 ("ctrl+k ctrl+k": "command:compact")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

"Newspapering" Feature #

What

New feature or mode referenced in codebase (details unclear from minified code).

Usage

Internal implementation detail.

Evidence

String literal at line 388067 ("Newspapering")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Enhanced Sandbox Security #

What

Significantly improved Unix domain socket security with ownership verification and stale socket cleanup.

Details

Socket directory ownership check: warns if directory owned by different user
Stale socket cleanup: removes sockets for non-running PIDs
Better seccomp filter path discovery for global @anthropic-ai/sandbox-runtime installations
Added .npm-global to seccomp binary search paths
Improved error messages with actionable installation instructions
Warning when seccomp binaries unavailable: "[Sandbox Linux] Seccomp binaries not available - unix socket blocking disabled. Install @anthropic-ai/sandbox-runtime globally for full protection."

Evidence

Socket ownership check at line 523583 ("Socket directory not owned by current user"), stale socket cleanup messages, seccomp search paths at line 95936 (".npm-global"), warning at line 96398

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Browser MCP Accessibility Tree Improvements #

What

MCP browser tool's accessibility tree output limit is now configurable.

Details

Default limit remains 50,000 characters
New parameter allows setting custom limits for clients that can handle larger outputs
More flexible description: "Output is limited to 50000 characters by default" (was: "Output is limited to 50000 characters")
New parameter: "Maximum characters for output (default: 50000). Set to a higher value if your client can handle large outputs."

Evidence

Description change at line 522359 and parameter at line 522387

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Updated Conversation Compaction Notification #

What

Compaction notification now shows "✻ Conversation compacted" with visual symbol instead of plain text.

Details

Old: Conversation compacted · {keybinding} for history
New: ✻ Conversation compacted ({keybinding} for history)
More visually distinct in transcript

Evidence

Notification text at line 410281 ("✻ Conversation compacted (")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Improved Permission Dialog Text #

What

Refined safety check messaging for workspace trust.

Details

Slightly more concise wording in safety prompt
Old: "Quick safety check: ... If not, take a moment to review what's in this folder first."
New: "Quick safety check: ... If not, take a moment to review what"
Message continues with context about Claude Code's file access capabilities

Evidence

Safety message at line 570322

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Guest Pass Notification Enhancement #

What

Clearer guest pass sharing notification in UI.

Details

More prominent formatting: "You have free guest passes to share · /passes"
Encourages user engagement with referral system

Evidence

Notification at line 562731

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Enhanced Task and Agent Status Logging #

What

More detailed logging for task claiming and agent operations.

Details

New logs: [inProcessRunner] Claimed task #N: {subject}
Task failure logging: [inProcessRunner] Failed to claim task #N
Task list check errors: [inProcessRunner] Error checking task list:
New logs for task assignment and completion

Evidence

Logs at lines 422622, 522622, 522628 with prefix [inProcessRunner]

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Layout Engine Identification #

What

Explicit layout engine logging for debugging rendering issues.

Details

Logs: "Layout engine: yoga" and "[render] initLayout starting/complete"
Helps diagnose UI rendering problems

Evidence

Engine log at line 174577, render logs at lines 182436-182438

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Message Structure Repair #

What

Automatic repair of malformed tool result pairings in conversation history.

Details

Detects and repairs missing tool_result blocks
Logs: ensureToolResultPairing: repaired missing tool_result blocks (X -> Y messages)
Prevents conversation corruption from improperly paired tool uses

Evidence

Repair logging at line 469512

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Team Workflow Enhancements #

What

Improved teammate communication and protocol handling.

Details

Operation descriptions now mention "discoverTeams to list available teams to join"
Better error messages for missing parameters in teammate operations
Clearer separation between message types (message, broadcast, request, response)

Evidence

Operation description updates in SendMessageTool schema, error messages for missing recipient, request_id, etc.

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Git Attribution System #

What

Removed automatic git commit trailer attribution system.

Details

Removed all "Attribution hook:" logging
Removed Claude-Generated-By: git trailers
Removed Claude-Escapes:, Claude-Permission-Prompts:, Claude-Session:, Claude-Steers: trailers
No longer tracks file contributions or calculates Claude percentage
Simplifies git workflow and removes potentially confusing commit metadata

Evidence

All Attribution: and Attribution hook: log strings removed from codebase (verified absent in v2.1.20)

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Removed `/commit` Keybinding #

What

Removed ctrl+k ctrl+k keybinding for /commit command.

Details

Previous binding: ctrl+k ctrl+c → /commit
Now unbound by default
Users can re-add via custom keybindings if desired

Evidence

Binding "ctrl+k ctrl+c": "command:commit" existed in v2.1.19 line 483280, not present in v2.1.20

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Removed Permission UI Elements #

What

Simplified permission request UI removed some verbose text and interactive elements.

Details

Removed: "Do you trust the files in this folder?"
Removed: "(shift+↑/↓ to select)" navigation hints
Removed: Several verbose permission dialog messages
Streamlined to clearer, more concise safety checks

Evidence

Strings like "Do you trust the files in this folder?", "shift+↑/↓ to select" removed from v2.1.20

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

PR Status Footer [Gradual Rollout]#

What

GitHub pull request status displayed in footer area.

Status

Feature-flagged behind tengu_pr_status_cli

Details

Settings option: "Show PR status footer" (enabled by default when flag is on)
Infrastructure exists in settings menu at line 480230
Will display PR status information in CLI footer when enabled

Evidence

Feature flag check at line 480226 (i4("tengu_pr_status_cli", !1)) with settings UI at line 480230 (label: "Show PR status footer")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Claude Code v2.1.20

Changesopen

Keybindings Customization Skill #

Related

Debug Logging to File #

Hard Fail Mode #

Package Manager Ownership Detection #

Related

SendMessageTool for Teammate Communication #

Related

Compact Conversation Keybinding #

"Newspapering" Feature #

Enhanced Sandbox Security #

Browser MCP Accessibility Tree Improvements #

Updated Conversation Compaction Notification #

Improved Permission Dialog Text #

Guest Pass Notification Enhancement #

Enhanced Task and Agent Status Logging #

Layout Engine Identification #

Related

Message Structure Repair #

Team Workflow Enhancements #

Git Attribution System #

Related

Removed `/commit` Keybinding #

Related

Removed Permission UI Elements #

PR Status Footer [Gradual Rollout]#

Anthropic’s official release notes