Claude Code Subagent Pattern: Parallel Exploration First, Single-Threaded Editing After — Set CLAUDE_CODE_SUBAGENT_MODEL for Cost-Tiered Execution
ClaudeFast·medium signal
The dominant production pattern for Claude Code subagents: run parallel exploration/research on cheaper models (Sonnet via CLAUDE_CODE_SUBAGENT_MODEL), then converge to single-threaded editing on Opus. Domain-based routing splits Frontend/Backend/Database agents. April 24 upgrade parallelized subagent and MCP server connections, materially reducing multi-agent startup overhead. Key insight: 90% of subagent failures are bad prompts, not architectural issues.