model-routing

Operate the model-routing switch (STANDARDS/model-routing.md, "The adopted rails"). Routing is delegation-based: stage work goes to four subagents at ~/.claude/agents/: Explore.md, Plan.md, Execute.md, Review.md. Every seat is DYNAMIC by default, resolved when a spawn is about to happen: no seat ever runs above the session's own tier, Plan and Review ride the session tier exactly, Explore resolves to haiku (the floor), and Execute runs sonnet capped at the session tier (callers on stronger sessions pass model: sonnet at spawn). A pin set through this command overrides the dynamic rule for that seat, verbatim.

Each file carries the live model: value and the seat memory (<!-- Seat: X --> near the end of the body): dynamic, or a pinned model. A dynamic seat's live value is model: haiku for Explore and model: inherit for the other three.

$ARGUMENTS is one of status (default when empty), dynamic, inherit, or set <stage> <model|dynamic>.

status: Read both values in all four files and report each seat (dynamic, or pinned to which model), the position (dynamic when every seat memory reads dynamic, inherit when all four live values read inherit, MIXED otherwise), and what the dynamic seats resolve to for THIS session given its model. Change nothing. Never tell the user to change their session model; the switch reads it, never sets it.

dynamic: Resume routing per the seat memories with the Edit tool: a seat remembering dynamic gets its dynamic live value (Explore model: haiku, others model: inherit); a seat remembering a pin gets that pin back. Report what changed.

inherit: Routing off. Set all four live model: values to inherit, leaving every seat memory untouched (the memory is what a later dynamic restores). Every stage then follows the session model.

set <model|dynamic>: <stage> is one of explore, plan, execute, review. set <stage> dynamic returns that seat to the dynamic rule (memory dynamic, live value per the mapping above). set <stage> <model> with a model tier your harness accepts (for example haiku, sonnet, opus) pins the seat: update the memory, and unless the position is currently inherit, set the live value to match. Never accept inherit as a seat value; it is a position, not a seat. Reject anything else with the valid options. Warn once when pinning a premium tier: premium spawns run without an approval prompt, so the cost surfacing is the seat's own self-report line, after the fact. A pin is honored verbatim, even above the session tier; an explicit choice is the user's to make.

Notes, state them when relevant rather than dumping them every run:

• New agent files hot-register mid-session, and live-value edits apply to the next spawn without a restart. The one exception: same-named overrides of built-ins (Explore, Plan) apply from the next session start.
• CLAUDE_CODE_SUBAGENT_MODEL is never part of this switch; it is the emergency cost ceiling only, since it flattens every subagent to one model.