THIS IS A REAL F*CKING GOLDMINE Anthropic engineers just revealed the most powerful multi-model pipeline for Claude Code The move: chain Sonnet, Haiku, and Opus into an automated conveyor where each model handles only what it does best Maximum development velocity with zero context waste: lightweight models do the heavy lifting, while the frontier model drives architectural strategy You just launch Claude Code like this: CLAUDE_CODE_SUBAGENT_MODEL=haiku claude --model sonnet here's how it splits: → Sonnet 5.5 drives the primary session, writes clean code, and directly applies diffs → Haiku 5.5 swarms the codebase in parallel: instant grep scans, call-site tracing, and spec retrieval → the Opus 5.5 architect subagent oversees overall system design and signs off on the final diff → you stop drowning your expensive frontier model in thousands of lines of raw terminal logs Opus only steps in at three critical moments: → before locking a multi-file architectural plan → when a test breaks twice at the exact same failure site → before staging the final commit and assembling a pull request Sonnet builds · Haiku scans · Opus reviews Prompt cache preservation under the hood: Sonnet's primary session keeps its prompt cache prefix active at a 90% discount, while Haiku subagents spawn in isolated working environments and dissolve without polluting your main conversation window the full tree > Sonnet 5.5 runs the primary session and writes surgical code edits > subagent-search maps repository structure on Haiku 5.5 in read-only mode > subagent-grep pinpoints function call sites and returns concise structured summaries > subagent-audit verifies test diffs inside a temporary worktree without touching your branch > subagent-architect on Opus 5.5 approves the final pull request > hard automated ceilings abort looping diff attempts after two consecutive failures paste the tree and this prompt into Claude Code ↓ "Reconfigure my Claude Code setup around this tree: • Run the main session on Sonnet 5.5 and set CLAUDE_CODE_SUBAGENT_MODEL=haiku in ~/.claude/settings.json • Create specialized subagents in .claude/agents/: search, grep, and audit on Haiku 5.5 with tools: Read, Grep, Glob, plus architect on Opus • Configure worktree isolation for test runners so temporary edits never pollute active branches • Add one rule to CLAUDE.md: delegate all codebase exploration to Haiku, summon architect after two identical test failures, and enforce diff audit before git staging Show every change as a diff first. No edits until I say go" code.claude.com/docs/en/sub-… save it, you'll need it