| name | spar |
| description | Open a gated, multi-round critique episode with a different-model subagent that attacks your assumptions before you commit to a consequential, uncertain decision. Use on "pair", "spar", "rubber duck", "get a second opinion", "discuss amongst yourselves", or "consult another model before committing". |
Spar
Get a sharp second opinion from a different model before you commit to a
consequential decision. This is a pairing skill with one divergence: between
agents there is no ego to protect, so the best pairing is sparring — the
partner is adversarial in service of the work. Keep the structure of pairing —
a shared goal and the driver holding the pen — and drop the ego-protecting
hedging that turns review into a rubber stamp.
What this is
- You are the driver. You hold the pen. The pair never implements, never
decides, and has no veto. It advises; you integrate or reject.
- The pair is a different model than you. A genuine second perspective
requires a different model, not an echo of your own reasoning. The pair runs as
a rubber-duck subagent (a "duck"). When the driver is GPT-5.5, the default duck
is Opus 4.8; when the driver is an Opus model, default to a strong GPT model.
The operator or caller may pin a different model. If the named default model is
unavailable, pick the strongest available model that is different from the
driver — a different model is the requirement, the specific name is only a
default.
- It is gated, not ambient. You do not consult on every change. You open a
deliberate episode when a decision is both consequential and uncertain.
- Once opened, it is dialogic. Gate the entrance, not the depth. A single
review pass is not sparring; run several short rounds while they keep resolving
the same decision.
When to open a sparring episode
Open one when you are about to make, revise, or abandon a consequential
commitment under uncertainty. That is the whole rule; the cases below just
instantiate it: