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90 episodes · 30 fps · 2 cameras · 320×240 h264

strands-isaaclab-tictactoe

A Franka arm in NVIDIA Isaac Lab plays tic-tac-toe. A Strands Agent picks the moves through four game tools, the arm picks each token from a tray and puts it on the board, and every move is recorded as a LeRobot v3.0 episode with strands-robots' DatasetRecorder.

one full game: overhead (left) and front (right) cameras, 4x speed

Game g00: the agent plays X against a minimax opponent and draws. Left: overhead camera, right: front camera, 4× speed. Full-speed mp4 · final board · agent transcript.

games 10: 6 agent vs minimax (agent alternates X/O), 4 agent vs agent. All 10 draws.
episodes / frames 90 / 29,070 at 30 fps (1 episode = 1 pick-and-place move, ~10.8 s)
cameras observation.images.overhead and observation.images.front, 320×240 RTX, fixed
observation.state 31-D = 9 Franka joint pos + end-effector pos (3) + gripper command (1) + board one-hot (9 cells × X/O = 18)
action 9-D joint position targets (7 arm + 2 fingers) from the scripted DiffIK pick-and-place controller
task strings 13, e.g. "place X in the center cell", "place O in the top-left cell"
placements 90 / 90 (100 %), all first attempt · placement error mean 1.78 mm, max 4.2 mm
vision check overhead-camera board vs simulator: 1 disagreement in 100+ board reads (a stale frame right after reset, see Limitations)
checks strands verify_dataset ok · LeRobotDataset load ok · video decode ok · NaN/inf = 0 · Hub round-trip ok

Results

game mode agent plays result placements error mean / max (mm) vision disagreements wall (s)
g00 agent vs minimax X draw 9/9 1.78 / 4.2 1 162.9
g01 agent vs minimax O draw 9/9 1.76 / 3.5 0 151.7
g02 agent vs minimax X draw 9/9 1.78 / 4.2 0 157.9
g03 agent vs minimax O draw 9/9 1.76 / 3.5 0 152.8
g04 agent vs minimax X draw 9/9 1.78 / 4.2 0 159.6
g05 agent vs minimax O draw 9/9 1.82 / 3.5 0 152.6
g06 agent vs agent X + O draw 9/9 1.78 / 4.2 0 191.5
g07 agent vs agent X + O draw 9/9 1.78 / 4.2 0 190.3
g08 agent vs agent X + O draw 9/9 1.78 / 4.2 0 192.4
g09 agent vs agent X + O draw 9/9 1.78 / 4.2 0 189.6

About 105 s of each game is the robot (9 moves × ~11.7 s) and the rest is model time. Total ≈ 28 min on one L40S. Per-game logs are in games/: game.json (summary + every LLM turn), moves.jsonl (per-move placement error, grasp, vision board), transcript.md (the full agent conversation with tool calls).

How it works

 strands venv                                            Isaac Lab venv (strands_robots on PYTHONPATH)
 ┌──────────────────────────────────────┐  JSON lines   ┌─────────────────────────────────────────────┐
 │ Agent(tools=[get_board, place_mark,   │  over TCP     │ ttt_server.py (Isaac Lab InteractiveScene)   │
 │              reset_game, render_board])│ ───────────▶ │  Franka HIGH_PD + 3×3 board + 5 X / 5 O tokens│
 │ opponent: minimax or a 2nd Agent      │ ◀─────────── │  DiffIK pick→place, overhead + front cameras  │
 │ referee: turn order, legality         │               │  strands DatasetRecorder: 1 move = 1 episode  │
 └──────────────────────────────────────┘               └─────────────────────────────────────────────┘

The game tools are plain Strands @tool functions (from examples/ttt_tools.py, trimmed):

from strands import Agent, tool
from strands.models import BedrockModel

@tool
def get_board() -> dict:
    """Look at the board: simulator truth + the overhead camera's view, whose turn it is, game status."""
    r = game.state()                      # server: sim token poses -> cells, and colour segmentation on the overhead camera
    return {"status": "success", "content": [{"text": ascii_board(r["board"]) + f"\ncamera agrees with sim: {r['agree']}"}]}

@tool
def place_mark(cell: str) -> dict:
    """Have the robot pick one of your tokens from the tray and place it on a cell ("center", "top-left", 1-9)."""
    r = game.place(mark, parse_cell(cell), by=name)   # server: DiffIK pick -> place, records one DatasetRecorder episode
    return {"status": "success", "content": [{"text": f"placed {mark} in {cell} (error {1000 * r['place_err_m']:.1f} mm)"}]}

agent = Agent(model=BedrockModel(model_id="global.anthropic.claude-opus-5-5"),
              tools=[get_board, place_mark, reset_game, render_board],
              system_prompt="You are playing tic-tac-toe ... call place_mark exactly once per turn ...")
agent("Let's play tic-tac-toe. You are X. Place your marks with the robot. You go first.")

On the server side each move is written through strands' recorder:

from strands_robots.dataset_recorder import DatasetRecorder

rec = DatasetRecorder.create(
    repo_id="cagataydev/strands-isaaclab-tictactoe", fps=30, robot_type="franka_panda",
    joint_names=JOINTS, action_names=ACTIONS,                     # 9 Franka joints / 9 joint targets
    camera_keys=["overhead", "front"], camera_dims={"overhead": (240, 320), "front": (240, 320)},
    extra_state_specs=[("ee_pos", ["x", "y", "z"]), ("gripper_cmd", ["close"]),
                       ("board", [f"{cell}.{m}" for cell in CELL_NAMES for m in "XO"])],
    task="play tic-tac-toe", root="runs/prod1/ds", use_videos=True)
for obs, act in move_frames:                      # every physics/render frame of one pick-and-place
    rec.add_frame(obs, act, task="place X in the center cell", camera_keys=["overhead", "front"])
rec.save_episode()                                # one episode per move; rec.finalize() at the end of the run

Reproduce

# Isaac Lab in its OWN venv (its pins clash with strands; strands never imports it)
uv venv --python 3.12 ~/il && uv pip install --python ~/il/bin/python --prerelease=allow \
  --index https://pypi.nvidia.com --index-strategy unsafe-best-match "isaaclab[rsl-rl,isaacsim]==3.0.0rc1" lerobot==0.6.1
export OMNI_KIT_ACCEPT_EULA=YES          # you accept the NVIDIA Omniverse / Isaac Sim EULA yourself
git clone https://github.com/strands-labs/robots && export STRANDS=$PWD/robots
# 1. start the Isaac Lab game server (logs to a file, protocol on a TCP port)
cd examples && PYTHONPATH=$STRANDS ~/il/bin/python ttt_server.py --port 8765 --log server.log &
# 2. play from the strands venv (needs Bedrock credentials; set STRANDS_MODEL_ID)
PYTHONPATH=$STRANDS python play_games.py --port 8765 --schedule agent_vs_minimax:6,agent_vs_agent:4 --alternate \
  --video all --out runs/prod1 --record runs/prod1/ds --repo_id cagataydev/strands-isaaclab-tictactoe

ttt_server.py --mock runs the whole agent/tool/vision/recording stack on CPU with a numpy stand-in for Isaac Lab.

Use it

from lerobot.datasets.lerobot_dataset import LeRobotDataset

ds = LeRobotDataset("cagataydev/strands-isaaclab-tictactoe")
print(ds.num_episodes, ds.num_frames, ds.fps)          # 90 29070 30
f = ds[0]; f["observation.state"].shape, f["action"].shape, f["observation.images.overhead"].shape, f["task"]
# (31,) (9,) (3, 240, 320) 'place X in the center cell'

Check it with strands:

from huggingface_hub import snapshot_download
from strands_robots.verify_dataset import verify_dataset

root = snapshot_download("cagataydev/strands-isaaclab-tictactoe", repo_type="dataset")
report = verify_dataset(root, expected=90)
assert report["ok"], report["problems"]

The language-conditioned task strings make this a small goal-conditioned pick-and-place set (13 goals), e.g. for behaviour cloning with strands' lerobot_local train_policy provider (not run for this card):

from strands_robots.tools.train_policy import train_policy
train_policy(action="train", provider="lerobot_local", dataset_repo_id="cagataydev/strands-isaaclab-tictactoe",
             output_dir="runs/smolvla_ttt", steps=20000, batch_size=32, extra={"policy_type": "smolvla"})

Provenance

  • strands-robots: main with strands-labs/robots#4227 (DatasetRecorder, verify_dataset); recorded from feat/isaaclab-trainer @ fa66fc68
  • Strands Agents with Amazon Bedrock, model global.anthropic.claude-opus-5-5; opponent: exact minimax
  • Isaac Lab 3.0.0rc1 · Isaac Sim 6.1.0.0 · PhysX · FRANKA_PANDA_HIGH_PD_CFG · DifferentialIK (DLS) · lerobot 0.6.1
  • GPU: 1× NVIDIA L40S (46 GB) · recorded 2026-09-29, run prod1

Limitations

  • Simulation only. No real Franka; no sim-to-real claims.
  • The robot motion is scripted, not learned: the agent chooses where, a DiffIK pick-and-place controller does how. The dataset is expert demonstrations of that controller, labelled by the agent's chosen goal.
  • Little variety in games. Minimax is deterministic and the model plays nearly the same way every time, so the 10 games end on only 3 distinct final boards (all agent-vs-agent games and every agent-as-X game repeat the same sequence). Moves and frames differ slightly between games; the goals do not. Perfect play from both sides always draws.
  • Vision: the one disagreement was a stale RTX frame read right after a reset (the overhead camera still showed the previous game's O). The agent noticed it, trusted the simulator and said so. Fix: render a few frames after reset.
  • Isaac Lab runs in a separate process because its pins (Python 3.12, torch, warp) clash with the strands venv; strands has no built-in tool for step-by-step control of an Isaac Lab scene yet.

License

license: other: our generated data under CC-BY-4.0, plus NVIDIA notices. See LICENSE.md. The recorded trajectories, camera video, GIF/PNG and transcripts are user-generated content made with Isaac Sim (NVIDIA Omniverse License Agreement §2.1 allows distributing it); the table, board and tokens are procedural primitives. No NVIDIA Content is redistributed: the Franka Panda USD comes from NVIDIA's asset server under your own EULA acceptance. Code in examples/ is Apache-2.0 (as strands-robots) on top of Isaac Lab (BSD-3-Clause). Running Isaac Sim requires accepting the NVIDIA EULA.

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