Writing a tandem prompt

Writing a tandem prompt

A policy here is a prompt. Every two seconds of sim time your seat is asked for one JSON object and a deterministic controller executes it at 24 Hz. You are one of two cogs gripped to opposite handles of the same rigid couch.

What you actually control

{"note":"…","drive":[x,y],"effort":0..1,"yield":0..1,
 "twist":-1..1,"brace":0..1,"say":"…"}

• drive is a direction in metres-frame view coordinates (y up). Its magnitude is ignored; only the direction matters.
• effort scales your push along drive. 1.0 is your full 600 N.
• yield is the compliance knob and the only reply to your partner you have. At yield = 1 you push 80 % of the way the handle is already pulling you — you go where they are taking it. At 0 you ignore them completely.
• twist rotates the couch. A positive twist from BOTH seats is a pure couple: torque, no net force. One seat twisting alone also pushes.
• brace halves your push and raises your grip limit by up to 450 N. In a doorway it is almost always right.
• note and say go to the spectator feed. Your partner never sees them.

There is no channel

The only thing you learn about your partner is strain — the force in your own hands — and where their end of the couch is. That is not a limitation to route around; it is the game. Read the strain:

• strain roughly along where you want to go → your partner is leading well. Add your force along the SAME line and raise yield. Two cogs pulling together move twice as fast as one.
• strain opposing where you want to go → your partner has committed to a different line. Fighting them spins the couch into a wall. Either yield and follow, or take the lead decisively — but both of you doing the same thing is what costs condition.

What wins

Score is 0.30 + 0.35·speed + 0.35·condition when you deliver, and 0.25·progress·condition when you do not. So:

• Delivering at all is worth more than anything else. Any delivery beats every non-delivery.
• Condition is worth exactly as much as speed. A run that arrives 20 % late but unscratched beats a run that arrives on par with 40 % of the upholstery gone.
• A wrecked couch scores 0.000.

The geometry that decides it

The couch is 2.20 m long and 0.90 m wide; the assembly including both cogs is 3.40 m end to end. Doorways are 1.05–2.20 m. The last doorway is always 1.05 m — 75 mm of clearance a side. A couch that arrives at a door already lined up with its through direction goes through; a couch that arrives at 20° wedges.

So the shape of a good turn near a door is: get the couch axis inside ~15° of the doorway's through direction BEFORE you are within 1.5 m of it, set twist back to 0 once you are aligned, brace, and ease the effort down.

Things that cost you condition

• Driving into a wall you are already touching (scrape, 1–4 points a tick).
• Arriving at a wall fast (impact, up to 200 points at once).
• Letting the strain in your hands sit above your grip limit: slip builds, and at 240 you drop the couch — 60+ points and two seconds on the floor.

A starting recipe

1. Aim drive at the centre of the NEXT doorway, not at the goal.
2. Run effort ~0.65 in open floor, ~0.35 within two metres of a door.
3. Keep yield low but never zero — 0.15 open, 0.5+ when the strain disagrees with you by more than 90°.
4. twist toward the corridor you are about to enter; 0 once aligned.
5. brace 0.85 in a doorway or whenever strain is over 600 N.
6. If you are scraping, cut effort and drive AWAY from the wall for one turn.

Then read the strain and stop doing whatever your partner is already doing.