Claude Code's three-tier model split mirrors Jev's decision approach
A look at Claude Code's Advisor tool, where Haiku explores, Sonnet writes code, and Opus steps in only at key checkpoints, with Jev engineering described as the same idea one layer down.
THIS IS ABSOLUTE F*CKING GENIUS Anthropic just quietly shipped the native Advisor tool in Claude Code, and paired with the new Haiku 5.5 it completely breaks multi-model economics The idea: run Sonnet 5.5 as main builder, swarm Haiku 5.5 as high-speed read-only scouts, and keep Opus 5.5 on call as the expert advisor Opus-grade judgment on every architectural fork, zero Opus burn on routine file audits, grep searches, or lint passes Launch Claude Code with the native advisor flag: claude --model sonnet --advisor opus how the workload divides: -> Haiku 5.5 swarms parallel exploration: repo tree mapping, grep call site searches, and API spec parsing at 340 tok/s -> Sonnet 5.5 leads the main terminal session: writes implementations, refactors code, and runs test suites -> Opus 5.5 stays on call as advisor: receives the full conversation transcript and intervenes only on high-leverage checkpoints -> you stop burning Opus context on routine terminal iteration Opus only steps in at three specific moments: -> right before a plan locks -> the second an identical error hits twice -> right before declaring a complex task complete how the Advisor tool works under the hood: -> Server-Side Tool: runs server-side on Anthropic infrastructure, ingesting full multi-turn context without polluting local memory -> Capability Ranking: Claude Code validates model hierarchies upfront so Opus 5.5 advises Sonnet 5.5 and Haiku 5.5 -> Prompt Cache Lock: preserved prefix caching keeps 1M+ token context ingestion sub-second across repeated consultations -> Terminal Telemetry: inspect the full advisor reasoning transcript in real time simply by pressing Ctrl+O Haiku explores. Sonnet builds. Opus reviews JEV engineering is the exact same move one layer down: deterministic forks (file selection, tool dispatch, fast retry vs abort) clear in sub-milliseconds, so the frontier models only handle genuine forks the full architecture tree: > Sonnet 5.5 runs the primary session, writes implementations, and executes tests > search scout maps the repo structure on Haiku 5.5 at 340 tok/s > grep tracer locates all call sites on Haiku 5.5 at 340 tok/s > docs parser extracts schemas and specs on Haiku 5.5 at 340 tok/s > Opus 5.5 stands on call as advisor, evaluating plans and reviewing diffs > JEV resolves instant deterministic routing in sub-milliseconds paste the tree and this prompt into Claude Code: "Reconfigure my Claude Code setup around this multi-model architecture: 1. Run the primary session on Sonnet 5.5 with Opus 5.5 as advisor via --advisor opus 2. Spawn three read-only Haiku 5.5 subagents: search (repo mapping), grep (call sites), docs (API references) 3. Add one rule to CLAUDE.md: consult the advisor before locking a plan, after repeating the same error twice, and before final task handoff 4. Press Ctrl+O to inspect advisor guidance before applying recommendations 5. Route fast deterministic forks through JEV, show all changes as diffs first" -> http://code.claude.com/docs/en/advisor bookmark this, you will use it on every major codebase
This post quotes another post: x.com/mirku21/status/2098836008468992471