# HEART Track 3: Advanced

**For products that act on their own, use an AI brain, run fleets, or are machines that move: what to read, what to skip, and when you are done**

**Status:** Reading guide, November 2026. Part of the [HEART Standards Family](HEART-Standards-Family.md). It adds no requirements.
**Read first:** [Track 1: Basic](HEART-Track-1-Basic.md) and [Track 2: Intermediate](HEART-Track-2-Intermediate.md), all of both. This page lists only what Track 3 adds.

---

## In one minute

Track 3 is a HEART that **acts**. A rule, another system or an AI can start a change, and the HEART decides whether it may run. Risky changes wait for a person who is really there. One command stops all automatic action, at once.

- **Feature Set:** `full` (`card.level`), with the `control` module (API Standard, Section 2.1).
- **Autonomy Level:** A3, A4 or A5.
- **Claim when done:** for example *HEART Full · A3 (A4 for connectivity) · self-tested*.

Track 3 has **three stops**. Stop as soon as your product is covered.

| Stop | You need it when | Autonomy | Extra reading |
|---|---|---|---|
| **3A. Acting, without a brain** | The product suggests fixes for a person to approve, or runs rules a person adopted | A3, A4 | about 1 hour 20 minutes |
| **3B. With a brain** | An AI model explains, plans or proposes fixes; or the product fixes new problems by itself; or it embeds a HEART Core | A3 to A5 with a model | about 1 hour 40 minutes more |
| **3C. Fleets and machines** | One command goes to many systems; or the product is a robot, heavy machine, vehicle, drone, ship or spacecraft | any | 10 minutes, plus the roadmap. **Most of this is planned, not yet in the standard.** |

**A3 is here, not in Track 2,** because suggesting a fix and waiting for a yes needs the approval gate and the stop control, and both are part of HEART Full ([Part 2](HEART-Part-2-Autonomy-Levels-1.0.md), Section 8).

---

## 1. Who it is for

| Stop | Examples |
|---|---|
| 3A | A thermostat that proposes a cheaper schedule and waits (A3); an online shop that restarts a stuck worker by a Playbook (A4); an air-conditioner controller that recalibrates a drifting sensor; a birdhouse camera whose zoom moves by adopted rules, inside limits |
| 3B | A greenhouse controller that asks a model for a better watering plan and runs it as a Trial; a photo editor with an AI assistant; any product that fixes problems nobody planned for (A5) |
| 3C | A Gateway rolling out an update to 2,000 systems; industrial and warehouse robots, excavators, haul trucks, cranes, autonomous tractors, drones, ships, rovers, landers and satellites |

**Road vehicles:** the roadmap decided that HEART does monitoring only for road vehicles, and sends no driving commands. Read Tracks 1 and 2, then the safety items of Stop 3C.

---

## 2. What you will build

### Stop 3A: acting, without a brain

| Piece | What it does | Defined in |
|---|---|---|
| **Capabilities and Actions** | Things the product can be asked to do, invoked with `POST /heart/v1/capabilities/{name}/invoke`; each run is an Action you can follow | Part 3, Sections 3.5 and 3.6; API Standard, Sections 6.2 and 6.3 |
| **The whole gate** | Every change, from `rule`, `ai`, `peer` or `human`, checked against one table; the allowlist with envelopes | Part 6, Section 2.3 |
| **Approvals** | `POST /heart/v1/actions/{id}/decision`: a person, never an AI, never the initiator, with proof of presence bound to the Action's digest; Actions that expire | Part 6, Section 3; API Standard, Section 6.3 |
| **No back doors** | New Playbooks, a wider allowlist, higher autonomy, trusting a peer: all `destructive` | Part 6, Section 4 |
| **Stop and the autonomy ceiling** | `POST /heart/v1/tending/stop`, with no approval and no internet; the ceiling `max` (`GET` and `PUT /heart/v1/tending/autonomy`), and the mode that follows from the current level: `observe`, `suggest`, `act` | Part 6, Sections 6 and 6.1; API Standard, Section 13.4 |
| **Playbooks (A4)** | "When this happens, do that", adopted by a person, run as `rule` inside the allowlist | Part 2, "A4"; Part 6, Section 4.2 |
| **Custom commands and guards** | The product's own commands, mapped to Modbus, CAN, G-code and more, with interlocks checked at the moment they run | API Standard, Section 14; Part 6, Section 9.1 |

### Stop 3B: with a brain

| Piece | What it does | Defined in |
|---|---|---|
| **Models suggest, systems decide** | Nothing a model says runs directly; instructions and data kept apart; budgets | Part 6, Section 5 |
| **The brain switch** | A brain only through a Command Center, only while holding a signed lease; cut at once or when the lease runs out; every answer signed | Part 2, Rule 7; Part 6, Section 6.2; API Standard, Section 7.4; Command Center profile |
| **HEART Core** | The runtime inside the product: four tiers, grounded serving, Consultations, Proposals, envelopes, Trials with undo, learned Playbooks, the brainless state | Core Standard |
| **Model changes** | A new model passes the product's tests before use | Part 6, Section 7; API Standard, Section 11 |

### Stop 3C: fleets and machines

| Piece | What it does | Defined in | Status |
|---|---|---|---|
| **Fleet commands** | One command to many systems, in stages, paused on failures, approved at the Gateway | Part 6, Section 8; API Standard, Section 13.3 | In the standard and the reference Gateway |
| **Lifecycle and running work** | How, what and when for restarts; pause, resume and cancel at safe points | API Standard, Sections 6.3 (rule 5) and 13.2 (rule 3) | In the standard |
| **The brain switch for machines** | The Command Center, leases and auto mode for machines that are offline for days | Command Center profile | In the standard; the reference Command Center runs at heartcortex.ai |
| **Control authority, missions, hazardous commands, machine modules, machine profiles** | Who has control, link-loss rules, time-limited commands, arm-then-fire, two-person rules, ten modules, Part 8 profiles | Planned | **Planned. Not in the standard yet.** |

---

## 3. What to read, in order

Read [Track 1](HEART-Track-1-Basic.md), Section 3, and [Track 2](HEART-Track-2-Intermediate.md), Section 3, first. Then read up to your stop.

### Stop 3A: acting, without a brain

| # | Document | Read these sections | Time | Why |
|---|---|---|---|---|
| 1 | [Part 2: Autonomy Levels](HEART-Part-2-Autonomy-Levels-1.0.md) | In Section 4, "A3: Suggests" and "A4: Fixes known problems"; in Section 5, Rules 1, 3 and 5; Sections 6 and 10 | 10 min | What A3 and A4 demand, the stop rule, and areas such as "A4 for connectivity" |
| 2 | [Part 6: Human Control and Safety](HEART-Part-6-Human-Control-and-Safety-1.0.md) | Section 2.3 again, **every column** this time; Sections 4 (4.1 to 4.3), 6 and 6.1; Section 9.1 | 18 min | The whole gate, the allowlist and its envelopes, no back doors to power, stop and modes, and guards. **The heart of this track.** |
| 3 | [Part 3: Information Model](HEART-Part-3-Information-Model-1.0.md) | Sections 3.5, 3.6 and 6 | 6 min | Capabilities, Actions and the standard action names |
| 4 | [API Standard](HEART-API-Standard-1.0.md) | Sections 6.2, 6.3, 6.4, 13.2 (rule 10) and 13.4 | 12 min | Invoking, the approval flow, the digest, presence methods, cancelling at safe points, Trials' one exception, and autonomy control. Read 6.3 slowly. |
| 5 | [Part 1: Basics](HEART-Part-1-Basics-1.0.md) | Section 9 | 2 min | The ladder of five steps, for commands the standard does not know |
| 6 | [API Standard](HEART-API-Standard-1.0.md) | Sections 1.3, 14 (14.1 to 14.7) and 15; Appendix D if you write custom definitions | 12 min | Custom commands, mapping to native protocols, guards, native passthrough, and physical systems |
| 7 | [Security Advisory 2026-001](HEART-Security-Advisory-2026-001.md) | C1 and C2 | 5 min | Why an AI holding a person's login cannot approve, and why standing orders count as power |
| 8 | [Part 9: Testing and Certification](HEART-Part-9-Testing-and-Certification-1.0.md) | Sections 5.3, 6.1 and 6.5 | 17 min | Causing faults safely, the autonomy tests, and the gate, approval and stop tests |
| 9 | One guide close to your product | All | 30 min | [Online shop server](../guides/Online-Shop-Server.md) (A4 Playbooks), [air-conditioner controller](../guides/AC-Temperature-Controller.md) (HEART Full with `heartd`) or [birdhouse camera](../guides/Birdhouse-Camera.md) (Playbooks inside an envelope) |

**Stop 3A total:** about 1 hour 20 minutes without the guide. **Stop here if your product has no AI model and sends no fleet commands.**

### Stop 3B: with a brain

| # | Document | Read these sections | Time | Why |
|---|---|---|---|---|
| 10 | [Design Note 1: The Brain and the Heart](HEART-Design-Note-1-Brain-and-Heart.md) | Sections 1 to 5 | 7 min | Why the brain is cut and the heart never is, with one worked example |
| 11 | [Part 2: Autonomy Levels](HEART-Part-2-Autonomy-Levels-1.0.md) | In Section 4, "A5: Fixes new problems"; in Section 5, Rule 7 | 3 min | What A5 demands, and why A3 and above with a brain needs a switch |
| 12 | [Part 6: Human Control and Safety](HEART-Part-6-Human-Control-and-Safety-1.0.md) | Sections 5 (5.1 to 5.4), 6.2 and 7 | 10 min | Models suggest, systems decide; cutting the brain; changing the model |
| 13 | [API Standard](HEART-API-Standard-1.0.md) | Sections 4.4, 7.2, 7.3, 7.4 (rules 1 to 13), 11 and 13.2 (rules 11 and 12) | 12 min | The Reason format, the brain lease, signed answers, signals that only lower risk, and the `brain` and `evolving` modules |
| 14 | [HEART Command Center](HEART-Command-Center-1.0.md) | "In one minute" and Sections 1 to 11 | 15 min | Joining, leases, cutting, tripwires, the public log and blessed models |
| 15 | [Core Standard](HEART-Core-Standard-1.0.md) | Sections 1 to 9, 11 and 12. Read Section 7 (7.1 to 7.8) slowly. | 45 min | The Core inside the product: tiers, serving, Consultations, Proposals, envelopes, Trials, learned Playbooks, the brainless state, classes and robustness |
| 16 | [Part 9: Testing and Certification](HEART-Part-9-Testing-and-Certification-1.0.md) | Section 6.6, and the `P6-BRAIN-*`, `P6-TRIAL` and `P6-INJECT` rows of Section 6.5 | 5 min | The Core tests and the brain switch tests |
| 17 | One guide close to your product | All | 30 min | [Greenhouse irrigation](../guides/Greenhouse-Irrigation.md) (the brain proposes, a Trial with one approval and automatic undo) or [photo editing software](../guides/Photo-Editing-Software.md) (the Core inside an app) |

**Stop 3B total:** about 1 hour 40 minutes without the guide. **Stop here unless you send fleet commands or build a machine that moves.**

### Stop 3C: fleets and machines

| # | Document | Read these sections | Time | Why |
|---|---|---|---|---|
| 18 | [Part 6: Human Control and Safety](HEART-Part-6-Human-Control-and-Safety-1.0.md) | Section 8, and Section 9 again | 5 min | One command to many systems, and physical safety, which takes priority over everything |
| 19 | [API Standard](HEART-API-Standard-1.0.md) | Section 13.3 | 2 min | Staged rollout, pause, resume with a new approval, cancel |
| 20 | [Core Standard](HEART-Core-Standard-1.0.md) | Section 10 | 1 min | Where the Core sits in a control system: on the supervisory side, never in the loop |
| 21 | [Part 2: Autonomy Levels](HEART-Part-2-Autonomy-Levels-1.0.md) | Section 6, "Profiles may set a ceiling" | 1 min | A machine profile may cap your Autonomy Level (Part 8 is not written yet) |
| 22 | [Part 6: Human Control and Safety](HEART-Part-6-Human-Control-and-Safety-1.0.md) | Section 9 | 5 min | Where HEART sits beside a machine's safety system. Authority, missions, hazardous commands and machine profiles are **planned, not in the standard: do not claim any of them.** |
| 23 | One guide | All | 25 min | [Water pump station](../guides/Water-Pump-Station.md): the pattern for machines today. The PLC and its interlocks run the plant; HEART watches, explains and tells a person. |

---

## 4. What you can skip, and why

| Skip | Why |
|---|---|
| Stop 3B, if your product has no AI model | A3 and A4 need no model and no internet (Part 2, Section 8). Without a brain you need no Command Center (Part 2, Rule 7). |
| The Core Standard, if you do not embed a HEART Core | The Core is one way to build a Full HEART. If you build your own, the gate, Actions and stop come from Part 6 and the API Standard. Read Core Section 7 anyway if a brain proposes changes. |
| Stop 3C, if you send no fleet commands and nothing moves | Fleets are for Gateways with the `fleet` module. The machine extensions are planned only. |
| API Standard, Appendices A to C | Background: neighbouring standards, open items and references. |
| The roadmap's decisions for machines you do not build | Each decision says which machines need it. A warehouse robot does not need the space profile. |

---

## 5. Where to start: templates and simulators

### Templates and the reference implementation

**No template serves HEART Full yet.** The planned `rust-heart-core` and `browser-worker` templates will. Today, start from the reference implementation:

| Start from | For |
|---|---|
| [HEART Core in Rust](../heart-core-rs/README.md) (`heart-core-rs`, the `heartd` daemon) | HEART Full on embedded Linux, a server or a Gateway: the gate, presence checks, Actions, Playbooks, Trials, custom commands, the Gateway and fleet commands. Download it from [heartcortex.ai/downloads](https://heartcortex.ai/downloads). |
| The Core as WebAssembly or a Rust library | HEART Full inside an app, as in the photo editor guide |
| `esp32-full` | An ESP32 that asks a cloud model to explain its alerts through a Reasoning Gateway (F3) and takes physical commands only after a press of its own button (F4). It claims Basic. |

The brain switch is in the standard, the reference Core and `heartd`, the Python and ESP32 templates, and the Command Center at heartcortex.ai.

### Simulators

These three claim *HEART Basic · A1* in their Card, because they are not rated Full implementations. They show Track 3 behaviour.

| Simulator | Stop | What it shows |
|---|---|---|
| [Online shop server](../onlineShopSimulator/README.md) | 3A | Three Playbooks on the allowlist for `rule`, with daily limits and cooldowns: A4 behaviour. Destructive actions are never possible through HEART. |
| [Birdhouse camera](../birdhouseSimulator/README.md) | 3A | Two adopted Playbooks move the zoom inside an envelope; the infrared light, which shines on living birds, needs a person at the box |
| [Greenhouse irrigation](../greenhouseSimulator/README.md) | 3B | A clearly labelled mock brain proposes "water 20% less, in two steps"; one press of the button approves the whole Trial, which is watched and undone if it goes wrong |

The [thermostat](../thermostatSimulator/README.md) (Track 2) also previews A3: its mock AI only suggests, and every suggestion waits for a person.

---

## 6. The Part 9 tests that apply

All the tests of [Track 1](HEART-Track-1-Basic.md) and [Track 2](HEART-Track-2-Intermediate.md), plus these. Weights: **critical** 5, **must** 3, **should** 1. One failed critical test caps the rating at 3.9, *Unsafe*.

### Stop 3A

| Test | Weight | Applies to you when |
|---|---|---|
| `P2-AUTONOMY-CURRENT` | must | Full |
| `P2-ALL-1` | **critical** | Full |
| `P2-A3-1`, `P2-A3-2`, `P2-A3-3`, `P2-A3-4` | must | You claim A3 or higher |
| `P2-A3-5` | must | You claim exactly A3 |
| `P2-A4-1`, `P2-A4-2`, `P2-A4-3` | must | You claim A4 or higher |
| `P2-A4-4` | must | You claim exactly A4 |
| `P4-AUTH-SCOPE`, `P4-IDEMPOTENCY` | must | Full |
| `P6-GATE`, `P6-APPROVER`, `P6-PRESENCE`, `P6-PRESENCE-ONE-CALL`, `P6-AUTHORITY`, `P6-PHYSICAL` | **critical** | Full |
| `P6-PRESENCE-ENROL` | **critical** | You offer the `presence` module |
| `P6-MODE`, `P6-ALLOWLIST`, `P6-EXPIRE`, `P6-PLAYBOOK-ADOPT`, `P6-CANCEL-SAFE` | must | Full |
| `P6-STOP`, `P6-STOP-ONE` | must | A3 or higher |
| `P6-HALT` | must | You offer the `core` module and a `halt` capability |
| `P6-GUARD` | must | Your commands have guards |
| `SEC-05-AGENT-NOT-HUMAN`, `SEC-06-AUTHORITY-CHANGE`, `SEC-07-PRESENCE-REQUIRED` | **critical** | Full |

### Stop 3B

| Test | Weight | Applies to you when |
|---|---|---|
| `P2-A5-1`, `P2-A5-2`, `P2-A5-3` | must | You claim A5 |
| `P2-A5-4` | should | You claim A5 |
| `P5-AI` | must | It calls AI models |
| `P6-INJECT` | **critical** | It uses AI or `/serve` |
| `P6-TRIAL` | must | It has the `core` module, or runs Trials |
| `P6-BRAIN-LEASE`, `P6-BRAIN-SIGNED`, `P6-BRAIN-LOWER`, `P6-BRAIN-NOKEYS` | **critical** | It has the `brain` module |
| `P6-BRAIN-SAFE`, `P6-BRAIN-SELFCUT` | must | It has the `brain` module |
| `P6-BRAIN-RESTORE` | **critical** | It has `brain.restoreNeedsOwner` |
| `P6-BRAIN-OFFLINE-CAP`, `P6-BRAIN-RECONNECT` | **critical** | It has `brain.offline` (auto mode) |
| `P6-BRAIN-STEPDOWN` | must | It has `brain.offline` |
| `P7-UNDERSTAND`, `P7-NO-MODEL`, `P7-LIMITS`, `P7-RESTART` | must | You claim a Core class (Core-S, Core-M or Core-L) |

### Stop 3C

| Test | Weight | Applies to you when |
|---|---|---|
| `P6-FLEET` | must | A Gateway with the `fleet` module |
| `P6-FLEET-RESUME` | **critical** | A Gateway with the `fleet` module |
| `P6-FLEET-ONE-APPROVAL` | **critical** | A Gateway with the `fleet` module, or a system that pins a Gateway key |

There are no Part 9 tests yet for the planned machine extensions, and no Part 8 profile tests (Part 9, Section 6.8). Nothing in them can be claimed until they exist.

---

## 7. You are done when

### Stop 3A

- [ ] Everything on the [Track 1](HEART-Track-1-Basic.md) and [Track 2](HEART-Track-2-Intermediate.md) finish lines is still true.
- [ ] Every combination of risk and initiator, on and off the allowlist, in every mode, gives exactly the result in Part 6, Section 2.3.
- [ ] An AI, another program, the Action's own initiator and a person without proof of presence all fail to approve. The person an AI acted for, with valid proof, succeeds.
- [ ] As the AI, adding a Playbook, widening the allowlist or raising `max` is held for a person or refused.
- [ ] Stop works at once, degraded and offline, with no approval, by `POST /heart/v1/tending/stop` and by `PUT /heart/v1/tending/autonomy` with `max` 2: waiting Actions are cancelled, and new automatic Actions get `409 autonomy-stopped`.
- [ ] If you claim A4: a Playbook fault is fixed without asking, also offline, and a fault no Playbook covers gets a suggestion that waits.

### Stop 3B

- [ ] With every message to the Command Center blocked, the brain is cut when the lease ends; nothing is consulted, and Proposals are refused. The heart keeps working.
- [ ] No model provider key is anywhere on the product.
- [ ] Unsigned, wrongly signed, old and replayed answers and signals are rejected, and no signal can ever raise anything.
- [ ] A Trial runs on one approval, undoes itself when a guard fails, and ends `stopped` with its values restored when stop is pressed.
- [ ] If you claim A5: with the model disconnected, `autonomy.current` drops to 4 with `limitedBy: no-model`.

### Stop 3C

- [ ] A fleet command that is not `read` waits for a person at the Gateway, starts with a small first stage, and pauses at its first failure; resuming needs a new approval.
- [ ] Your machine's safety functions work with the HEART absent, stopped or hacked, and HEART sits only on the supervisory side.
- [ ] You claim nothing from the roadmap until it is in the standard and tested.

When every test in Section 6 that applies passes, you can say, for example: **HEART Full · A4 (A3 for actuators) · self-tested**. You have read everything the standard asks of your product. The rest of the standard is reference.