# AI proposes. Independent checks constrain. A human decides.

Tetheract is an independently constrained physical-operation layer between AI or high-level intent and real machines. It is built around one idea: an AI agent can suggest what a machine should do, but it never gets to act on its own judgment. Every proposal is checked independently and decided by a person, and every step is recorded.

> Status: simulation only. Tetheract does not control real hardware today and makes no safety, certification or compliance claims. A supervised test on a real motorized linear stage is planned only after a qualification checklist and an independent review, and no independent reviewer has been named yet.

## How agents and humans work together

1. **The agent proposes.** An AI agent or planner suggests an action, such as a stage move, along with its rationale. Tetheract treats the agent as an untrusted proposer.
2. **Tetheract checks, independently of the agent.** Authority checks confirm the proposal is backed by a valid, unexpired, unrevoked and non-replayed grant. Constraint checks test it against position, velocity, force and temperature limits, sensor freshness, units, coordinate frames and interlocks.
3. **The operator sees everything in one place.** The proposal, the check results, the current machine state and the predicted outcome appear together, with a plain-language explanation of anything that was denied.
4. **The operator decides.** Approve and execute, edit and re-check, reject with a reason, or take manual control, which pauses agent proposals.
5. **Only approved commands run.** Execution goes through a typed machine adapter. The agent cannot approve its own proposals.
6. **Every handoff is recorded.** Each step lands on a shared evidence timeline as a signed, hash-chained receipt showing who acted, when and why.

The result is a working arrangement where the agent does the planning and the human keeps the authority. An attention queue tells the operator what needs a decision, and incident review is built from the same evidence receipts.

## Who it is for

- Lab-automation teams exploring AI-assisted operation of equipment such as motorized stages, who want a person to stay in charge of every physical action.
- Lab-automation integrators who want to evaluate a typed adapter contract and an operator approval flow in simulation.
- Qualified independent reviewers. An independent review is the open requirement before the first supervised real-hardware test.

Tetheract is early-stage software for evaluation in simulation. It is not ready for production use or for unsupervised operation of any machine.

## What exists today, in simulation

- A detailed simulator of a motorized linear stage, including homing, limit switches, encoder tracking against commanded position, stalls and missed steps.
- A lab protocol demo in which an AI planner proposes a multi-step stage scan and the operator approves each motion, with predicted and measured results shown side by side.
- An operator console with an attention queue, denial explanations, manual takeover and incident review.
- Passkey-only sign-in with viewer, operator and admin roles, and a fresh passkey check for each consequential action.
- Signed, hash-chained evidence receipts that can be exported and verified for tampering.
- Fault injection (stale, spoofed or missing sensors, unit and frame mismatches, partial actuation, timeouts, network partitions) and adversarial tests (forged, expired and replayed grants, prompt-injected proposals, attempts to rewrite limits, tampered updates).
- Additional simulated fixtures on the same adapter contract: a two-axis gantry and in-process Modbus TCP and OPC UA simulators.

## What Tetheract is not

- It does not control real hardware. A real-hardware adapter exists only as an interface with actuation disabled.
- It has no safety rating or certification, it has not had an independent safety review, and it makes no regulatory compliance claims.
- It is not a hosted service. It runs on your own computer and listens only on the loopback address by default.
- It is not suitable for autonomous operation without human supervision.

## Learn more

- [How it works](https://tetheract.com/how-it-works): The layers of the system, what each check does, how operators decide, how evidence is recorded, and the gates before any real hardware test.
- [FAQ](https://tetheract.com/faq): Direct answers to common questions about status, hardware, approvals, sign-in, certification, pricing and source code.

Canonical page: https://tetheract.com/