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Quatern overview

Quatern is an AI agent for robot software. You describe what the robot should do; Quatern writes the localization and planning code, tests it against your robot's own sensor recordings, and only then lets it run, behind a human approval and a live watchdog.

pipx install quatern
quatern

New here? Start with the Quickstart. It takes a catalog robot from install to a verified run in the simulator in a few minutes, with no robot and no API key.

What Quatern does

  • Writes the code. Ask in plain English. The agent writes a localizer and a planner for your robot as a module: a directory with a module.toml and sources, in any language. Without a sign-in, Quatern uses its reference localizer and planner, tuned to your recording.
  • Proves it offline. The module runs in a sandbox against a recording from your robot's real sensors. Quatern computes the checks itself, so no module grades its own work. See How verification works.
  • Asks before anything moves. A stack only deploys after it passes verification, you pin it, and a person answers the deploy gate.
  • Watches it run. A separate watchdog process checks the robot 20 times a second and stops it when the plan, the sensors and the map stop agreeing. See Safety.
  • Keeps a record. Every run ends in a receipt that says what was commanded, what was observed, and how it stopped.

The loop

Every change goes through the same five steps, whether the agent wrote it or you did.

The Quatern loop Write, then verify against a recording, then the human gate, then the watchdog during the run, then a run record. A failed verification goes back to write. Write agent or your module Verify replay a recording Gate a person approves Watchdog checks at 20 Hz Run record receipt on disk NOT READY: fix and try again a check trips: the robot stops
The loop. Verification, the gate and the watchdog are the three places a change can be stopped.
  1. Write. The agent produces a localizer and a planner module for the goal you gave it. You can also bring your own module and verify it with quatern verify --module <dir>.
  2. Verify. quatern verify replays a recorded sensor session through the module in a sandbox, cross-checks the sensors against each other, builds a map, plans to your goal and prints a plain-English report ending in READY or NOT READY. Each run is saved as a stack.
  3. Gate. You pin the stack you trust with quatern pin. quatern deploy checks the preconditions, shows the DEPLOY GATE screen with the plan and the abort limits, and asks Proceed past the gate? THE ROBOT WILL MOVE. [y/N].
  4. Watchdog. While the robot runs, a separate process compares the plan, the localizer and every sensor, and calls the robot's emergency stop on the first check that fails.
  5. Run record. The run ends with a printed RECEIPT and a write-once JSON file: final state, what was commanded and observed, the stop, and any warnings.

Where it runs

Quatern runs on your computer, in a terminal. It talks to robots through three backends:

Backend What it is
sim2d Quatern's built-in 2D simulator, with worlds room, hallway and warehouse_aisle. The default target for catalog mobile robots.
mock A lightweight simulated robot. Catalog arms (sim_arm, ur5e) run here.
ros2 A real robot, or Gazebo, over ROS 2.

Your recordings, maps, stacks and receipts stay on your machine in ~/.quatern. See Accounts and usage for what the agent sends when you're signed in.

Next steps