Claude Code v2.1.16 / Changelog

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13 entries

Changesopen

Agent Swarms - Multi-Agent Coordination #

What

Spawn and coordinate multiple AI agents working in parallel on a project. Teams have a 1:1 correspondence with task lists (Team = Project = TaskList).

Usage

# Create a team
claude
> Use TeammateTool with operation "spawnTeam" and team_name "my-project"

# Spawn teammates via the Task tool with team_name and name parameters
> Use Task tool to spawn a teammate named "researcher" for team "my-project"

Details

Create teams with spawnTeam operation
Teams automatically create corresponding task list directories at ~/.claude/tasks/{team-name}/
Team configuration stored at ~/.claude/teams/{team-name}/config.json
Teammates can communicate via write (single recipient) or broadcast (all teammates)
Graceful shutdown workflow with requestShutdown → approveShutdown/rejectShutdown
Plan approval workflow for teammates: approvePlan/rejectPlan
Cleanup team resources when done with cleanup operation

Evidence

Ds7() at line 417104 (TeammateTool prompt, contains "# TeammateTool", "spawnTeam", "requestShutdown")

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

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.178 Named-Teammate Agent Swarms (TeamCreate/TeamDelete Removed)

Dynamic Team Joining #

What

Agents can discover and request to join existing teams, with leaders approving or rejecting requests.

Usage

# Discover available teams
> Use TeammateTool with operation "discoverTeams"

# Request to join a team
> Use TeammateTool with operation "requestJoin", team_name "my-project", proposed_name "helper"

# Leader approves the request
> Use TeammateTool with operation "approveJoin", target_agent_id "helper", request_id "join-123"

Details

discoverTeams lists teams from ~/.claude/teams/ that you can join
requestJoin sends a join request to the team leader
Leader receives join_request message and uses approveJoin or rejectJoin
Configurable timeout for join requests (default 60 seconds)

Evidence

rY2() (requestJoin handler), oY2() (approveJoin handler), aY2() (rejectJoin handler) with operations "requestJoin", "approveJoin", "rejectJoin"

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

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.32 Agent Teams Simplified

Task Tools for Shared Task Management #

What

New set of tools for creating and managing tasks that are shared across team members.

Usage

# Create a task
> Use TaskCreate with subject "Implement API endpoint" and description "Create the /users endpoint"

# List all tasks
> Use TaskList to see available tasks

# Update task status or ownership
> Use TaskUpdate with id "1" and status "in_progress" and owner "researcher"

# Get task details
> Use TaskGet with id "1"

Details

TaskCreate: Create new tasks with subject, description, and optional metadata
TaskGet: Retrieve a task by ID
TaskUpdate: Update task status, owner, description, or blocked_by relationships
TaskList: List all tasks showing ID, status, owner, and subject
Tasks support dependency tracking with blocks and blockedBy fields
When a task is completed, blocked tasks become unblocked

Evidence

Or7 at line containing "Create a new task in the task list", Xr7 (TaskCreate prompt), DD1 (TaskGet name), Lr7 (TaskUpdate description)

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

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

Native iTerm2 Split Pane Support for Teammates #

What

Teammates appear as split panes in iTerm2 on macOS, providing visual separation for each agent.

Usage

# Setup is prompted automatically when spawning teammates in iTerm2
# Requires it2 CLI tool installation via pip/pipx/uv
pip install it2

Details

Automatic detection of iTerm2 environment
Guided setup flow to install it2 CLI tool
Split panes created for each teammate with color-coded borders
Falls back to tmux if iTerm2 setup is not completed
Option to prefer tmux over iTerm2 with --teammate-mode tmux

Evidence

ITermBackend class with methods createTeammatePaneInSwarmView, isAvailable, contains "[ITermBackend] Creating pane", "iTerm2 Split Pane Setup", "✓ iTerm2 split pane support is ready"

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

In-Process Teammate Execution #

What

Spawn teammates within the same process instead of separate tmux panes, useful for non-interactive sessions.

Usage

# Automatically used in non-interactive sessions
# Can be explicitly requested with --teammate-mode in-process
claude --teammate-mode in-process

Details

Teammates run as async tasks within the same process
Enabled by default in non-interactive sessions
Each teammate has its own abort controller for graceful shutdown
Supports all the same operations as pane-based teammates
Resource cleanup handled automatically

Evidence

InProcessBackend class at line 6920 with type = "in-process", "[InProcessBackend] spawn() called", "[InProcessBackend] Started agent execution"

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

Mailbox-Based Inter-Agent Communication #

What

Filesystem-based mailbox system for asynchronous communication between team members.

Details

Each agent has an inbox at ~/.claude/teams/{team-name}/inboxes/{agent-name}.json
Messages include timestamp, sender, and content
Automatic delivery of messages when agent turn ends
Queued messages for busy agents delivered after their turn completes
Supports permission requests/responses, shutdown requests, plan approvals

Evidence

TeammateMailbox functions writeToMailbox, readMailbox, markMessagesAsRead with logging "[TeammateMailbox] Wrote message to", "[TeammateMailbox] readMailbox"

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

New CLI Flags for Teammate Mode #

What

New command-line flags for configuring teammate spawning behavior.

Usage

claude --teammate-mode tmux          # Force tmux backend
claude --teammate-mode in-process    # Force in-process backend
claude --teammate-mode auto          # Auto-select based on environment

# Used internally when spawning teammates:
claude --agent-id <id> --agent-name <name> --team-name <name>
claude --agent-color <color>
claude --plan-mode-required
claude --parent-session-id <id>

Details

--teammate-mode: Choose how teammates are spawned (tmux, in-process, auto)
--agent-id, --agent-name, --team-name: Identity flags for teammate sessions
--agent-color: Assign a color for the teammate's UI
--plan-mode-required: Require plan approval before implementation
--parent-session-id: Link to parent session for analytics

Evidence

CLI flag construction at lines 5617-5622, 7145-7193 with flags "--agent-id", "--agent-name", "--team-name", "--agent-color", "--plan-mode-required"

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

Git Worktree Support for Teammates #

What

Each teammate can work in their own git worktree for isolated file modifications.

Details

Worktrees created automatically for teammates when needed
Cleaned up via git worktree remove or manual removal on cleanup
Supports parallel work on the same repository without conflicts

Evidence

removeWorktree() function with git worktree remove --force, "[TeammateTool] Removed worktree via git", worktreePath field in teammate objects

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

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.47 Agent Worktree Cleanup

Enhanced Backend Registry for Pane Management #

The backend registry now intelligently selects the appropriate pane backend:

Detects iTerm2 and checks for it2 CLI availability
Prefers iTerm2 native split panes when available
Falls back to tmux with informative messaging
Supports user preference for tmux over iTerm2

Evidence

[BackendRegistry] Selected: iterm2 (native iTerm2 with it2 CLI), [BackendRegistry] Selected: tmux (fallback in iTerm2, it2 setup recommended)

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

Teammate Preview UI #

New UI for viewing teammate status and activity:

Shows teammate name, status (running/idle/awaiting approval), and progress
Color-coded teammate indicators
Idle time tracking
Interactive controls: kill, shutdown, cycle mode, prune idle

Evidence

hs7() function (teammate preview component), "shift+↑/↓ to select teammate", "select · Enter view · k kill · s shutdown · p prune idle"

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

Slack MCP Tool Recognition #

Added recognition for Slack MCP tools to enable better integration with authenticated Slack access.

Evidence

"mcp__claude_ai_Slack__slack_send_message", "mcp__claude_ai_Slack__slack_read_thread", "mcp__slack__send_message", "mcp__slack__read_thread"

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

Remote IDE Server Path Handling #

Improved path handling for remote IDE server directories (.vscode-server, .cursor-server, .windsurf-server).

Evidence

Path checking includes ".vscode-server", ".cursor-server", ".windsurf-server" at line 1669-1674

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

First Render Timing Logging #

Added startup performance logging to track first ink render time.

Evidence

"[render] first ink render: ${Math.round(process.uptime() * 1000)}ms since process start"

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

6 entries

Bug Fixesopen

#

Fixed potential issues with teammate context initialization during session reconnection ([Reconnection] Initialized agent context from session)
Fixed message marking logic in mailbox system (markMessagesAsRead, markMessageAsReadByIndex with proper lock handling)
Fixed cleanup of in-process teammate tasks when aborted ([TeammateTool] Aborted controller for in-process teammate)
Fixed worktree removal when git command fails (falls back to manual rm)

Perfetto Tracing Removed #

The Perfetto performance tracing feature has been removed from this release.

Evidence

Removed PERFETTO_TRACING flag check, removed trace writing functions writePerfettoTrace, writePerfettoTraceSync, removed all [Perfetto] logging statements

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

HybridTransport POST Debugging Removed #

Removed verbose HTTP POST debugging from the hybrid transport layer.

Evidence

Removed "HybridTransport: POST URL =", "HybridTransport: POST success", "HybridTransport: POST failed" logging

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

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.9 HybridTransport for Remote Sessions

Teammate Mode Requirements #

tmux mode: Requires tmux installed on your system. Start a tmux session before spawning teammates.
iTerm2 mode: Requires macOS with iTerm2 and the it2 CLI tool installed.
in-process mode: No external dependencies, but teammates run in the same process.

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.227 Teammate pane creation serialised under tmux and iTerm2

Task List Coordination #

When working in teams:

Use TaskList periodically to find available work
Claim tasks by setting yourself as owner with TaskUpdate
Mark tasks completed when done
Check TaskList again to find newly unblocked work

Environment Variables for Teammates #

Spawned teammates have these environment variables:

CLAUDE_CODE_AGENT_ID: Unique identifier for the agent
CLAUDE_CODE_AGENT_TYPE: Role/type of the agent
CLAUDE_CODE_TEAM_NAME: Name of the team
CLAUDE_CODE_PLAN_MODE_REQUIRED: Whether plan approval is required

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.40 Team Plan Auto-Approval

Claude Code v2.1.16

Changesopen

Agent Swarms - Multi-Agent Coordination #

Related

Dynamic Team Joining #

Related

Task Tools for Shared Task Management #

Related

Native iTerm2 Split Pane Support for Teammates #

In-Process Teammate Execution #

Mailbox-Based Inter-Agent Communication #

New CLI Flags for Teammate Mode #

Git Worktree Support for Teammates #

Related

Enhanced Backend Registry for Pane Management #

Teammate Preview UI #

Slack MCP Tool Recognition #

Remote IDE Server Path Handling #

First Render Timing Logging #

Bug Fixesopen

#

Perfetto Tracing Removed #

HybridTransport POST Debugging Removed #

Related

Teammate Mode Requirements #

Related

Task List Coordination #

Environment Variables for Teammates #

Related

Anthropic’s official release notes