# Claude Code v0.2.42 Changelog
Changes
8 itemsBatch Tool Execution (Call Tool) #
A powerful new tool that allows executing multiple tools in a single request for improved performance:
- Tool Name:
BatchTool(displayed as "Call" to users) - Purpose: Run multiple independent tool operations at once to reduce context usage and latency
- Execution: Tools are executed in parallel when possible, otherwise serially
- Usage Example:
claude> /call
{
"invocations": [
{
"tool_name": "Bash",
"input": {
"command": "git blame src/foo.ts"
}
},
{
"tool_name": "Glob",
"input": {
"pattern": "**/*.ts"
}
},
{
"tool_name": "Grep",
"input": {
"pattern": "function",
"include": "*.ts"
}
}
]
}
MCP Server Timeout Configuration #
- New Environment Variable:
MCP_TIMEOUT - Default: 5000ms (5 seconds)
- Usage: Set custom timeout for MCP server operations
MCP_TIMEOUT=10000 claude # Set 10 second timeout
- Benefit: Allows users to adjust timeout for slower MCP servers
Non-Blocking MCP Server Startup #
- MCP server initialization no longer blocks the application from starting
- Improves startup time when MCP servers are slow to initialize
- Application becomes responsive immediately while MCP servers load in background
Enhanced Help Mode #
- New help display showing keyboard shortcuts when help is open
- Displays:
! for bash mode- Quick access to bash command mode/ for commands- Access slash commands- Platform-specific newline instructions:
- Mac with Karabiner:
shift + ⏎ for newline - Terminal supporting backslash:
\⏎ for newline - Default:
Backslash (\) + Return (⏎) for newline
WebFetch Security Enhancement #
- Updated security requirement: URLs must be provided directly by the user (removed "in the current or a previous message" qualifier)
- Strengthens security by requiring explicit user-provided URLs
HTTP Request Handling #
- Switched from native
fetchto axios for better control - Added proper redirect handling with
maxRedirects: 0 - Improved error messages with HTTP status codes
- Better content length limiting with
maxContentLength
Release Notes Update #
- Added v0.2.41 release notes documenting:
- MCP server startup timeout configuration via MCP_TIMEOUT
- Non-blocking MCP server startup behavior
Code Organization #
- Renamed internal functions and variables for consistency
- Improved stream handling using named imports
- Better error handling in HTTP requests
- Enhanced batch tool execution with proper progress tracking and error aggregation