Claude Code · Source-level changelog

Version 1.0.64

Package @anthropic-ai/claude-code Diff v1.0.63 → v1.0.64
4
Features & Changes
0
Bug Fixes
0
In Development
0
Env Vars / Flags

Changes

4 items

New Features #

Agent Model Configuration

  • Configurable AI models for agents: Agents can now specify which Claude model they should use (Sonnet, Opus, or Haiku)
  • "Inherit" model option: Agents can inherit the model from the parent conversation, allowing for flexible model usage
  • Environment variable override: New CLAUDE_CODE_SUBAGENT_MODEL environment variable to globally override agent model selection
  export CLAUDE_CODE_SUBAGENT_MODEL=haiku
  claude # All agents will use Haiku regardless of their configuration

️ Enhanced Agent Management

  • Edit Model option: New menu option "Edit model" when managing agents through the interactive UI
  • Model validation: Agent files now validate model specifications against allowed values (sonnet, opus, haiku, inherit)
  • Agent file model syntax: Agents can specify their model in the frontmatter:
  name: my-agent
  description: Description of what this agent does
  model: opus  # New field
  tools: [Read, Write, Bash]

MCP (Model Context Protocol) Improvements

  • Resource management: Better handling of MCP resources with proper cleanup and state management
  • Tool namespacing: MCP tools are now properly namespaced with mcp__<server-name>__ prefix for better organization
  • Connection stability: Improved reconnection logic for SSE (Server-Sent Events) based MCP connections

Status Hook Integration

  • External status monitoring: New internal status hook system for external tools to monitor Claude Code's status
  • JSON-based status communication: Status information can be passed to external commands via JSON
  • Configurable timeout: Status hook operations have a 5-second default timeout

Improvements #

UI/UX Enhancements

  • Model display in agent info: Agent model selection is now displayed in the agent information
  • Better model descriptions: Clear descriptions for each model option:
  • Sonnet: "Balanced performance - best for most agents"
  • Opus: "Most capable for complex reasoning tasks"
  • Haiku: "Fast and efficient for simple tasks"
  • Inherit: "Use the same model as the main conversation"

Bug Fixes

  • Removed duplicate MCP management code: Cleaned up redundant MCP server management implementation
  • Fixed agent file path handling: Improved path resolution for agent files across different locations
  • Better error messages: More descriptive error messages for invalid agent configurations

Technical Changes #

️ Architecture

  • Modular agent system: Agents now have a more structured configuration with model preferences
  • Improved type safety: Better validation of agent properties including model selection
  • Resource cleanup: Proper cleanup of MCP resources when connections are terminated

Compatibility

  • Backward compatible: Existing agents without model specifications default to Sonnet
  • Survey system: Added force display option via CLAUDE_FORCE_DISPLAY_SURVEY environment variable for testing

Usage Examples #

Creating an agent with a specific model:

# In your .claude/agents/fast-analyzer.md
name: fast-analyzer
description: Quick code analysis using Haiku for speed
model: haiku
tools: [Read, Grep, Glob]

Your agent prompt here...

Using the inherit model option:

# If you're using Opus in your main conversation
claude --model opus

# This agent will also use Opus when called
name: inherit-example
description: Uses the same model as the parent conversation
model: inherit
tools: [*]

Global model override:

# Force all agents to use Haiku for faster responses
export CLAUDE_CODE_SUBAGENT_MODEL=haiku
claude

This update focuses on giving users more control over agent behavior through model selection, improving the MCP integration, and enhancing the overall agent management experience.