# aura

**aura is a "game engine for traders."** It is a Rust framework — and a
playground — for authoring trading strategies as composable dataflow nodes,
backtesting them deterministically and massively in parallel, validating them
(sweep / Monte-Carlo / walk-forward), and freezing a validated strategy into a
standalone bot with a broker connection. Its differentiator is the **World**: a
program that constructs and orchestrates whole *families* of backtests, not the
single run.

This README is a discoverability map of the shipped `aura` CLI — *what commands
exist and what they do*. It deliberately keeps per-flag detail light; the two
authoritative sources for exact syntax are always:

- `aura <command> --help` — the exhaustive flag grammar.
- The design ledger (`docs/design/INDEX.md`) and glossary (`docs/glossary.md`)
  — the concepts and invariants behind the surface.

## Build & run

aura is a Cargo workspace. Build everything and you get one binary named `aura`:

```sh
cargo build --workspace          # binary at target/debug/aura
cargo build --workspace --release  # optimized, at target/release/aura
```

Invoke it as `aura <command> …` (examples below use the plain name).

## Concepts in one breath

- **Blueprint** — a serialized signal graph as data: a param-generic
  `price → bias` node graph. A blueprint file (`blueprint.json`) is the unit a
  downstream consumer loads and executes or varies.
- **Open vs. closed** — a blueprint with unbound (free) numeric knobs is *open*;
  one with every knob bound is *closed*. A plain `exec` wants closed; naming a
  knob as a campaign axis (or an `exec --override`) is what reopens it.
- **Family** — the set of runs a campaign document's process pipeline produces
  over a blueprint (a sweep grid, a Monte-Carlo seed set, a walk-forward window
  sequence). Families are persisted in a content-addressed store and can be
  listed, ranked, and reproduced.
- **Axis** — one named, sweepable knob of a blueprint (e.g. `fast.length`),
  bound with a comma-separated value list. A **gang** fuses several sibling
  knobs into one axis (one value drives all members).

## Executing a document

`aura exec <target>` (#319) is the one executor verb: `<target>` is either a
loaded **blueprint** file (a single synthetic run) or a **campaign document**
(a `.json` file or its registered 64-hex content id — instruments × windows ×
strategy × param axes × process, see `docs/authoring-guide.md` §3). `graph`
renders a blueprint's structure so a mis-wire is visible before a run.

| Command | Purpose |
|---|---|
| `aura exec <bp.json>` | Run one backtest of a **closed** blueprint and print its report. An open (free-knob) blueprint is refused with a clean error — bind it, or vary it as a campaign axis. |
| `aura exec <bp.json> --override <node.param>=<value>` | Reopen one **bound** param for this single execution only (the value is recorded raw in the manifest); repeatable. |
| `aura exec <bp.json> --tap <name>=<fold>` | Subscribe a declared tap to a fold (`record`/`count`/`sum`/`mean`/`min`/`max`/`first`/`last`) for this run; repeatable. |
| `aura graph <bp.json>` | **Render** the blueprint's structure as an interactive HTML DAG so a mis-wire is visible before a run. Omit the file to render the built-in sample; a named-but-unreadable file is a usage error. |
| `aura graph introspect --params <bp.json\|id>` | **Discover** a blueprint's open, sweepable knobs. Prints each as `<name>:<kind>`, bound params trailing `default=<value>`. Run this first to learn the axis names for a campaign document. |
| `aura exec <campaign.json\|id> [--parallel-instruments <n>]` | Execute a **campaign document** — a grid family, gates, walk-forward, Monte-Carlo, and cross-instrument generalization per its process document, one cell per (strategy, instrument, window). |
| `aura runs families` | List every persisted family (id, kind, member count). |
| `aura runs family <id> [rank <metric>]` | List one family's members, optionally ranked best-first by an R metric (e.g. `sqn_normalized`, `expectancy_r`). |
| `aura reproduce <family-id>` | Re-derive every member of a persisted family from the content-addressed store and check it is bit-identical (the C18/C1 determinism guarantee). |

**Important contract — every open knob is mandatory on a campaign axis.** A
campaign document's `strategies[].axes` must name every open knob
`graph introspect --params` lists: there is no default value — pin a knob you
don't want to vary with a single-value axis (`{"kind":"I64","values":[4]}`).
Omitting one is a clean error naming the missing knob, not a silent default.

Use `aura exec --help` for the exact flag grammar, `docs/authoring-guide.md`
for the campaign document shape (data window, naming, presentation/emit).

## Authoring & introspecting topology

A blueprint is authored declaratively from a **JSON op-list**: an ordered list
of by-identifier construction ops replayed against the standard node vocabulary.
Adding a new node *type* to that vocabulary is Rust, not JSON — see
`docs/authoring-guide.md`, §0, "Authoring a new node in Rust".

| Command | Purpose |
|---|---|
| `aura graph build` | Read an op-list document on **stdin**, build the blueprint, and print its canonical JSON to **stdout** (no trailing newline — it is the content-addressed artifact). |
| `aura graph introspect --vocabulary` | List every node type available to op-lists. |
| `aura graph introspect --node <T>` | Show one type's input ports, output fields, and param paths (with the bind-value form). |
| `aura graph introspect --unwired` | Read a *partial* op-list on stdin and list its still-open interior slots. |
| `aura graph introspect --content-id` | Read an op-list on stdin and print the SHA-256 content id of the blueprint it would build. |
| `aura graph introspect --identity-id` | Read an op-list on stdin and print the SHA-256 **identity id** — the topology's debug-name-blind id, so two documents (or an op-script and a Rust-built blueprint) expressing the same topology print the same id. Combinable with `--content-id` (both ids, one per line, content id first). |

### Op-list shape

Each element is one op, tagged by `"op"`. Node params are bound with the **typed
`Scalar` form** — a tagged, capitalized-kind object: `{"I64": 5}`, `{"F64":
1.5}`, `{"Bool": true}`. A worked example (an SMA-crossover → bias signal):

```json
[
  {"op":"source","role":"price","kind":"F64"},
  {"op":"add","type":"SMA","name":"fast","bind":{"length":{"I64":2}}},
  {"op":"add","type":"SMA","name":"slow","bind":{"length":{"I64":4}}},
  {"op":"add","type":"Sub"},
  {"op":"add","type":"Bias"},
  {"op":"feed","role":"price","into":["fast.series","slow.series"]},
  {"op":"connect","from":"fast.value","to":"sub.lhs"},
  {"op":"connect","from":"slow.value","to":"sub.rhs"},
  {"op":"connect","from":"sub.value","to":"bias.signal"},
  {"op":"expose","from":"bias.bias","as":"bias"}
]
```

Piping this document into `aura graph build` emits a `blueprint.json` you can
then feed to `exec` above:

```sh
aura graph build < crossover.ops.json > crossover.bp.json
aura graph introspect --params crossover.bp.json
```

The op kinds are `source`, `input`, `add`, `feed`, `connect`, `expose`, `tap`,
`gang`, `doc`, and `use` (`tap` declares a recorded measurement point on an
interior wire; `doc` declares the composite's one-line meaning, required at
register — C29; `use` splices a registered blueprint in as a nested composite,
by content id or label; `add` additionally takes an `args` object for
**arg-bearing** types (`Session`, `LinComb`, `CostSum`) — structural,
non-scalar construction consumed before `bind`; see the authoring guide). See
`aura graph introspect --node <T>` for a type's exact ports and the op-script
grammar in the design ledger for the full semantics.

## Where to go deeper

- `aura <command> --help` — exhaustive, always-current flag grammar.
- `docs/design/INDEX.md` — the design ledger: architecture, invariants, the World.
- `docs/glossary.md` — canonical terminology (blueprint, family, axis, sweep /
  Monte-Carlo / walk-forward, R, content-id, …).