Cycle 0004: the reactive-semantics layer. The engine now merges multiple
timestamped sources into one chronological cycle stream (C3) and gates each
node's re-evaluation by a per-input firing policy (C5/C6) — both rails shipping
together, as the user required ("must sit right from the start").
- `Firing` (aura-core) — a per-input enum on `InputSpec`, where C8 places firing:
`Any` (mode A, fire-on-any-fresh + hold / as-of join) and `Barrier(u8)` (mode B,
all-fresh barrier / synchronizing join). Default-free; Sma/Sub declare
`Firing::Any`, so under a single source ticking every cycle their behavior is
unchanged (backward compatible — the 0003 fan-out/join DAG still emits
[None,None,None,2,2,2]).
- `SourceSpec` + the k-way merge (aura-engine) — `run` takes one
`(Timestamp, Scalar)` stream per source and merges them by (timestamp, source
index) (C4 ties by declaration order). One record = one cycle. This is the
permanent ingestion core; the Source trait + data-server IO (C3/C11) are a
later orthogonal cycle (the user scoped this cycle to the reactive semantics).
- Two read clocks, both load-bearing (resolves the 0003 audit's "0004 owns
cycle_id" with no write-only field): each push stamps the input slot with
`fresh_at` (the cycle_id — freshness epoch, C5: fresh iff fresh_at == cycle_id)
and `last_ts` (the data timestamp — barrier token, C6: a barrier group is
complete iff all members carry last_ts == T). The `fires()` predicate ORs the
groups; the ">=1 member fresh this cycle" clause is the once-per-timestamp
guard. Sample-and-hold falls out of the push model: a non-firing node pushes
nothing, so consumers keep seeing the held value via window[0].
Key design call, studied against RustAst (src/ast/rtl/streams/): the barrier
token is the data *timestamp*, not cycle_id. RustAst's
last_cycle_per_input.all(== cycle_id) synchronizes one source's fan-out but
cannot synchronize independent sources — under C4 four same-timestamp sources
are four different cycle_ids, so the cycle_id barrier never fires for C6's own
OHLC example. Substituting timestamp is the minimal faithful generalization
(fires both the diamond rejoin and the multi-source bar). Mode A and the k-way
merge are both new (RustAst had neither); RustAst's total_count push counter is
aura's already-built Column::run_count.
Both rails proven on identical sources, firing-only difference:
- mode A (AsOfSum): [None,None,120,130,140,240] — holds the slow input;
- mode B (BarrierSum): [None,None,120,None,None,240] — waits for timestamp
coincidence;
- mixed A+B (MixedSum): the OR-combine fires both when the barrier pair completes
(holding the as-of input) and when the as-of input ticks (holding the pair).
Plus determinism (C1, bit-identical re-run of each rail) and the three bootstrap
rejections re-expressed on SourceSpec.
Gates green (re-run by the orchestrator, not just the agent): cargo build/test
(30: aura-core 19 + aura-std 3 + aura-engine 8) / clippy --workspace
--all-targets -D warnings clean; surface-purity grep (no dyn-Any / Rc / RefCell)
clean — the harness doc phrases RustAst's model without the literal tokens to
avoid self-match.
refs walking-skeleton
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Architect drift review over 71c8f6e..dd5c3fa (deterministic-sim-loop).
Invariants hold: C1 (single-threaded, bit-identical re-run, alloc-free per-cycle
ring path), C7 (AnyColumn type-erased edges, Box<dyn Node> is the node object not
a dyn-Any payload, kinds checked once at bootstrap), C8/C9 (DAG wired, Kahn
rejects cycles, None forwards nothing = sample-and-hold seed). Column::run_count
already exists, so the C5 freshness primitive lives at the substrate — the
deferral is honest, not a hole.
Resolved [high]: the runtime type was named `Sim`, colliding with the glossary's
load-bearing distinction — `sim` is the disjoint *executable unit / parallelism*
framing, whereas the thing built here (a closed root graph of source + nodes +
observe under a clock) is by C20 / the glossary a **harness**. Renamed
`Sim` -> `Harness`, `sim.rs` -> `harness.rs`, and the module/exports/doc to match,
before any other code takes a dependency on the wrong term. Gates re-run green
(26 tests, clippy -D warnings, purity grep).
Resolved [med] (glossary gap): added an `edge` entry anchoring the new wiring
vocabulary (Edge / source target) to the glossary — record-reality per the boss
glossary-write authority.
Carry-on with forward notes (next-cycle owners, not fixes now):
- [med] C4 monotonic cycle_id has no realization in the runtime type yet (the
cycle clock is the record iteration; the explicit counter's first reader is
freshness). Cycle 0004 owns materializing it together with C5.
- [low] Sub declares lookback 1; once depth>1 join nodes exist, add a test
guarding C8's "a node never reads beyond its declared lookback".
Regression gate: profile regression list empty — architect is the sole gate,
now clean. Next direction: freshness-gated recompute + a second source (C5/C3).
Cycle 0003: aura-engine's first real content — a Sim that runs a wired DAG of
nodes deterministically, cycle by cycle. First point in the project where
authored nodes execute against data, not just under a hand-fed Ctx.
- `Sim` (aura-engine) — a bootstrapped, frozen root graph: a flat Vec<NodeBox>
(each node owns its input columns, the cycle-0002 shape) + an index edge
table, topologically ordered (Kahn). `bootstrap` sizes every input column from
its node's schema, kind-checks each edge and source target, and rejects
directed cycles — C7's "type check paid once at wiring" generalized to the
whole topology (`BootstrapError::{KindMismatch, BadIndex, Cycle}`).
- `run` — the deterministic loop: per record, forward the source value into its
target slots, evaluate nodes in topo order, capture the observed node's output
at eval time, and forward each `Some` output into its consumers' input columns
(a `None` forwards nothing — the structural seed of sample-and-hold). The loop
destructures `&mut self` into disjoint field borrows and allocates nothing on
the per-cycle path. This is the flat, monomorphized sharpening of RustAst's
reference-counted, interior-mutable observer push graph (C1/C7).
- `Edge` / `Target` (aura-engine) — producer->consumer and source->consumer wiring.
- `Sub` (aura-std) — a 2-input f64-difference node, so the loop is proven on a
real fan-out + join DAG (source -> {SMA(2), SMA(4)} -> Sub), with a determinism
assertion (C1: a second identical run is bit-identical).
Engine library depends only on aura-core; a test-only dev-dependency on aura-std
lets the integration test wire real Sma/Sub nodes. Sim carries a hand-written,
node-opaque `Debug` impl (Box<dyn Node> is not Debug; the impl prints
nodes.len() + the index/topology fields, needed by the bootstrap-rejection tests'
`unwrap_err`).
Deliberately deferred (recorded as decisions): freshness-gated recompute /
sample-and-hold (C5 -> cycle 0004, with the second source that makes it testable);
the explicit monotonic cycle_id counter (its first reader is freshness, 0004);
the Source trait + data-server ingestion + k-way merge (C3/C11); the builder API
(C19); the real sink + run registry (C18/C22).
Gates green: cargo build/test (26: 18 aura-core + 3 aura-std + 5 aura-engine)/
clippy -D warnings clean; surface-purity grep (no dyn-Any / Rc / RefCell) clean.
refs walking-skeleton
Correct the broker mechanism: a broker is an ordinary downstream consumer node (C8/C9), not an external plugin/subsystem. It consumes the position-event stream + price streams and emits an equity stream; several brokers (e.g. sim-optimal pip + realistic currency) can be attached to the same position table at once, yielding directly comparable equity curves. Updates C10, CLAUDE.md invariant 7, aura-engine/aura-std crate docs, and the day-in-the-life doc.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
C8: a node is producer/consumer/both — at most one output, pure consumers (sinks: chart/equity/logger) have none; records the node-role taxonomy the substrate requires (was wrongly 'exactly one output', contradicting pure consumers and C14). C3: merge by timestamp, normalizing source-native units (data-server Unix-ms) to the canonical epoch-ns of C7. aura-engine lib doc: broker is a downstream plugin over the position table (sim-optimal pip / realistic currency), not an in-strategy 'broker/portfolio node'. Plus a provenance line-wrap nit.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Cargo workspace aura-core -> aura-engine -> aura-cli (bin `aura`) plus nodes/ for hot-reloadable cdylib node crates. Crate bodies are intentionally API-free; types arrive from the first spec. Adds the skills profile (.claude/dev-cycle-profile.yml), the project CLAUDE.md with the eight domain invariants, and the design-ledger skeleton.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Brummel