Pandect states the law. The consumer decoders explain documents against it. Nexus compiles that attested prose into machine-readable specs and computes the actual deadlines and dollar amounts — for a licensed professional, with provenance defensible to a court, a client, or a malpractice carrier.
Where it sits
The portfolio's thesis: rules-based professional judgment is automatable, and the value flows to the party holding a document they didn't write. The system is deliberately decomposed so no layer can do another's job.
What it computes
Per-anchor offset / roll / calendar with earlier_of / later_of over fully-computed candidates. Reproduces the shipped meridian-1031 suite through the generic evaluator — and recovers the per-anchor roll meridian had to punt on.
src/deadlines.ts · dates.ts · holidays.ts
The magnitude twin, on a deliberately narrow grammar: single | min | max | sum + bracket selection. Anything richer lives in a domain hook — the RMD-divisor canary fails the build the instant core grows an operator.
src/quantity.ts
Conflict candidacy scoped to requirement ∧ jurisdiction ∧ counterparty — 14 independently-mandatory state filings can never collapse to one. Version resolution on both axes: the law as it was valid × as it was known.
src/conflicts.ts · versions.ts
Reproducible from (law hash, spec version, facts, as-of times). Knowledge-time is a malpractice-defense feature: "the obligation as it was known when I advised." Defensibility, not arithmetic, is what the customer pays for.
The audit · Fable 5 · 2026-07-10
Baseline: a doc-first repo with a locked v3 schema, a mature DeadlineSpec evaluator, 9 passing tests, and its charter living only in markdown. The audit produced five recommendations. All five were executed and committed (3b91c5d).
STRAWMAN.md's types existed only as prose. Now code: the NexusRule union, evaluate() with the Gate-1 degrade, the dual-version provenance chain, presenter types. The charter is enforceable, not aspirational.
src/contract.ts + contract.test.ts
The silent failure class — independently-mandatory duties collapsing to one "winner" — now structurally impossible. Same-scope contenders are surfaced for the professional, never auto-picked. Red #5 green.
src/conflicts.ts
A §7508A disaster postponement enacted in March, retroactive over a January trigger: as-known-in-February computes day 180; as-known-in-April computes day 300 — same trigger, both answers correct, both hash-pinned. Red #3 green.
src/versions.ts
The magnitude engine on the narrow grammar: the HOA §5720(b) $1,800 foreclosure gate reads a computed aggregate; the RMD divides in a domain hook, never in core. Red #4 now guards grammar and evaluator.
src/quantity.ts + quantity.test.ts
A composite anchor naming Feb 30 used to roll silently to March — a fabricated deadline. It now throws, like every unimplemented path. A thrown error is correct; a confidently wrong deadline is the worst failure.
src/deadlines.ts
The charter, in the type system
The engine never computes off a guessed trigger. An inferred trigger, a fact needing characterization, or a "reasonable time" deadline degrades to a grounding result that surfaces the fork for the licensed user. Credibility, not liability-withholding: a professional tool that fakes certainty is caught wrong once and never reopened.
The engine computes everything; presenters expose a licensed subset. A computed dollar amount reaching a consumer surface is a compile error, not a runtime check — the same discipline by which the grounding rails made "model-authored rule field" unrepresentable.
Portfolio synergy
The attested-rule registry behind pandectai.com. Nexus pins every computation to a Pandect rule by id + content hash and mirrors its attorney-attestation shape for the encoding.
vellum/Marque, Plainsight, Recourse and siblings decode institutional documents for consumers — structurally barred from computing. Nexus is the opposite end of the same posture spectrum, sharing the no-fabrication doctrine.
The shipped 1031-exchange deadline engine whose vitest suite is Nexus's fixed point — its punted filing-deadline roll is the case the compositional spec was designed to recover, and now does.
The rule-verification pipeline (audit → cross-review → trust promotion) that qualifies rules for Tier-1 use. Its encoding-fidelity checker resolves DeadlineSpec/QuantitySpec encodings through the Nexus evaluator.
Tollgate, Plumbline, Keystone and siblings run the Intake→Assist→Gate→Engine→Guard→Audit compliance pipeline for businesses. Deliberately separate doctrine — but the same rules-as-versioned-data spine and human-gate discipline.
Two attestations at two layers: Pandect's attorney attests the law; Nexus's encode-attestation certifies the encoding computes what the prose says. One attorney attests once; every computation for every client inherits that captured judgment.
Honest ledger
Unbuilt paths throw named errors rather than compute a wrong answer. The item that topped this list — wire nexus_eval_url — shipped the same day it was written (POST /api/evaluate, live on this domain; the endpoint refuses toll_spec-bearing specs rather than ignore them). Remaining, in rough order of leverage:
toll_spec suspend/resume) and business-day offset counting — the next evaluator capabilities a vertical will demand.