[Release] anthropics/claude-code v2.1.172: v2.1.172

Claude Code v2.1.172 introduces hierarchical sub-agent spawning (up to 5 levels deep), improves AWS region configuration handling for Bedrock, and adds a marketplace search feature. The release includes numerous bug fixes addressing context management, session stability, model selection, and UI responsiveness issues. Performance optimizations reduce CPU usage and improve message handling in long conversations.

Key Points

• •Sub-agents can now spawn their own sub-agents up to 5 levels deep, enabling more complex hierarchical agent workflows
• •Amazon Bedrock now reads AWS region from ~/.aws config files when AWS_REGION isn't set, matching AWS SDK precedence behavior
• •Added search bar to marketplace plugin browser for easier plugin discovery and selection
• •Fixed critical issue where sessions using 1M context without credits would get stuck; now automatically compacts back to standard limits
• •Resolved repeating error messages when conversations contained multiple images that couldn't be processed
• •Fixed model picker issues including doubled 1M-context suffixes, incorrect model availability filtering, and misleading slash prefixes
• •Improved performance by removing redundant message normalization and reducing UI re-renders during idle and parallel sub-agent execution
• •Fixed WebFetch wildcard domain rules (*.example.com) not matching subdomains in allow/deny/ask positions
• •Added model attribute to claude_code.lines_of_code.count OTEL metric for better observability
• •Fixed background session issues including directory isolation, EAUTH failures, and stuck agent states in the agent panel

Workflow Diagram

Concepts