model-router

name	model-router
description	Choose the right model and effort per task phase and apply it when dispatching subagents — strong model + high effort for planning and review, a cheaper model + lower effort for mechanical execution. Use when a task splits into plan / execute / review phases or you're spawning subagents.
model	inherit
effort	medium
allowed-tools	["Read","Task"]
triggers	["which model","route this","plan then implement","dispatch a subagent"]
tags	["models","effort","routing","subagents","cost"]

Model Router

Match the model and effort to the work. Reasoning-heavy phases deserve a strong model at high effort; mechanical phases run cheaper and faster. This cuts cost and latency without hurting quality where it matters.

The map

Defaults live in ${CLAUDE_PLUGIN_ROOT}/config.json under models.roles. Read it first; treat it as the source of truth and let the user override.

Phase / role	Model	Effort	Why
plan	strong (e.g. opus)	high	Design, trade-offs, architecture — errors here are expensive.
execute	mid (e.g. sonnet)	medium	Follow a plan, write code — throughput matters.
review	strong (e.g. opus)	high	Catch what execution missed; judge freshly.
cheap	small (e.g. haiku)	low	Formatting, renames, extraction, boilerplate.

effort scales how much the model deliberates. Use inherit to keep the session's current setting when a split isn't warranted.

How to decide

1. Is the task uniform and small? Don't split — do it in the session model at inherit. Routing has overhead; only pay it when phases genuinely differ.
2. Does it separate into plan / execute / review? Route each phase to its row above.
3. Is a chunk purely mechanical (rename across files, extract a constant, apply a format)? Send it to cheap.

Applying it to subagents

When you dispatch a subagent for a phase, request that phase's model + effort. State it explicitly, e.g. "planner: strong model, high effort". If the runtime rejects a model or effort value, surface the exact error — do not silently fall back to a weaker setting, since that changes the quality contract.

Pair with other skills

• Under agentic-loop, route the fix-planning step to plan and the apply step to execute or cheap.
• Log the routing choice as a decision via memory-keeper if it's a standing convention for the project ("Review always runs on opus/high").

Guardrails

• Never downgrade the reasoning phases to save money if correctness is at stake — a wrong plan or a missed review costs more than the tokens saved.
• Never upgrade mechanical work to a heavy model — it's slower for no gain.
• Respect explicit user model choices over these defaults, always.