claude
8688a60ded
The single-file ledger had grown to 2968 lines / ~42k tokens, mixing current design law with accreted history: 59 cycle-stamped realization blocks, 18 [HISTORY] passages, 22 supersession markers, and the C10 / C22 / C24 reframe sagas layered several supersessions deep. A code-grounding audit (31 agents, adversarially verified) confirmed 11 defects stated as current truth: stale crate homes from the C28 #288 roster split (cost nodes, PositionManagement, PositionEvent, Session), the renamed InputSpec->PortSpec, the pre-#241 project model in C16 and the open-threads section, a stale HarnessKind retirement deferral in C24, and three C28-internal inconsistencies. New shape, per the ailang precedent: - INDEX.md stays the sole addressable entry point: foundation, external components, a C-id-keyed contract map (one line per contract), and only the genuinely open architectural threads. - contracts/cNN-<slug>.md carries each contract's current truth only: Guarantee / Forbids / Why with ratified refinements integrated, plus a code-anchored Current state. All confirmed defects are fixed here; crate anchors were re-verified against the tree. - contracts/cNN-<slug>.history.md (18 sidecars) and INDEX.history.md preserve every superseded block verbatim, stamps and issue refs intact, under a frozen-record banner. Nothing was deleted: superseded design intent remains an addressable working-tree artifact, off the per-cycle audit walk. - Ledger discipline is now stated in INDEX.md: live files are edited in place at cycle close, superseded text moves verbatim to the sidecar, and a supersession marker in a live file is itself an audit finding. Every contract file was verified against its old text by an independent zero-loss pass (statement-by-statement) plus a code-accuracy spot check; C-ids and contract titles are unchanged, so existing C-id citations in code, tests, and issues resolve as before.
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C5 — Freshness-gated recompute and sample-and-hold
Guarantee. The cycle_id advances everywhere (a cheap counter), but a node
re-evaluates only when ≥1 of its own inputs is fresh this cycle (detected by
run-count); otherwise it holds its last output. Stale inputs contribute their
last (held) value.
Forbids. Recomputing every node every cycle ("push all" is true for the clock, not for recompute); treating a held value as missing.
Why. Total recompute does not scale to many sparse high-frequency sources; freshness-gating is the performance discipline that keeps the synchronous model fast.
Current state
Freshness is a run-count epoch. Each input slot carries SlotState { fresh_at, last_ts } (crates/aura-engine/src/harness.rs); a slot is fresh this cycle iff
fresh_at == cycle_id. The firing predicate fires re-evaluates a node when any
Firing::Any input is fresh this cycle, or when a barrier group completes (≥1
member fresh this cycle and every member carrying last_ts == ts) — the barrier
/ co-freshness machinery itself is C6.
A node that does not fire pushes nothing, so downstream consumers keep reading the
last value via window[0]: sample-and-hold falls out of the push model rather
than being a separate mechanism. A held value is a real past value, never treated
as missing.