Trust centre · engine 1.0.0-alpha.2 · intelligence 0.1.0

Trust centre

Everything the layer claims about its own correctness is measured, published and reproducible from the repository. Figures here are computed at build time or read from manifests written by the verification run; none is typed in.

Golden checks44/4416 groups across 7 packs

Property tests114/114monotonic 22/22 · marginal_le_100 22/22 · continuity 22/22 · deterministic 22/22 · zero 22/22 · analysis 4/4

Parameters with sources13145 distinct authority pages · as of 2026-10-30

Schedules2213 obligation rules · 7 jurisdictions

Published verification manifest

public/verification/latest.json

Verification · engine 1.0.0-alpha.2

run 2026-10-30

Golden checks: 44/44; statute worked examples
Property tests: 114/114; monotonic · marginal ≤ 100% · continuity · determinism
Oracle cross-check: 56,588 cases; 0 divergences · 22 schedules
Sources reachable: 38/44; probed 2026-10-30
Values confirmed: 91; 0 sources changed

Oracle cross-check

run 2026-10-30

Cases

56,588

Divergences

Schedules covered

22/22

Throughput

81k/s

Every schedule is evaluated across a grid of inputs and dates by the data-driven engine and by an independently written, hand-coded oracle; results must agree within 0.005. The oracle is test code and never serves users. All live schedules are covered.

Source watch

probed 2026-10-30 · source-watch/1.0

Sources

Reachable

Values confirmed verbatim

91/100

Content changed

Each authority page is fetched, hashed and searched for the parameter values the pack takes from it, in the number formats that jurisdiction uses. A value that is not found verbatim is not wrong; pages often state weekly or monthly figures, fractions or percentages differently. A changed hash opens a review, and a change to a published rate ships only as a new dated parameter.

Source	Jurisdictions	Status	Values	Drift	Fetched
GOV.UK trading and property allowances ↗	UK	200	2/2	new	2026-10-30 12:44
GOV.UK CGT allowances ↗	UK	200	1/1	new	2026-10-30 12:44
GOV.UK CGT rates ↗	UK	200	2/2	new	2026-10-30 12:44
GOV.UK marginal relief ↗	UK	200	2/3UK.CT.MR_FRACTION	new	2026-10-30 12:44
GOV.UK Corporation Tax rates ↗	UK	200	2/2	new	2026-10-30 12:44
GOV.UK tax on dividends (rates from 6 April 2026) ↗	UK	200	4/4	new	2026-10-30 12:44
GOV.UK Child Benefit tax charge ↗	UK	200	3/3	new	2026-10-30 12:44
GOV.UK Income Tax rates ↗	UK	200	5/6UK.IT.BRL	new	2026-10-30 12:44
GOV.UK income over £100,000 ↗	UK	200	1/1	new	2026-10-30 12:44
GOV.UK Marriage Allowance ↗	UK	200	1/1	new	2026-10-30 12:44
GOV.UK MTD for Income Tax ↗	UK	200	2/2	new	2026-10-30 12:44
GOV.UK threshold reduction to £20,000 ↗	UK	200	1/1	new	2026-10-30 12:44
GOV.UK National Insurance rates ↗	UK	200	3/6UK.NI.C1.PT, UK.NI.C1.ST, UK.NI.C1.UEL	new	2026-10-30 12:44
GOV.UK self-employed NI rates ↗	UK	200	6/6	new	2026-10-30 12:44
GOV.UK Employment Allowance ↗	UK	200	1/1	new	2026-10-30 12:44
GOV.UK pension annual allowance ↗	UK	200	3/3	new	2026-10-30 12:44
GOV.UK student loan repayment ↗	UK	200	7/7	new	2026-10-30 12:44
GOV.UK VAT registration ↗	UK	200	1/1	new	2026-10-30 12:44
Revenue: basis of charge ↗	IE	200	2/2	new	2026-10-30 12:44
Revenue: tax rates, bands and reliefs ↗	IE	200	5/5	new	2026-10-30 12:44
Revenue: USC rates and thresholds 2026 ↗	IE	200	7/7	new	2026-10-30 12:44
Revenue: current VAT rates ↗	IE	200	0/1IE.VAT.STD	new	2026-10-30 12:44
§ 32a EStG (VZ 2026) ↗	DE	502	0/0	unreachable	2026-10-30 12:44
§ 11 GewStG ↗	DE	502	0/0	unreachable	2026-10-30 12:44
§ 23 KStG ↗	DE	502	0/0	unreachable	2026-10-30 12:44
§ 4 SolzG 1995 ↗	DE	502	0/0	unreachable	2026-10-30 12:44
§ 3 SolzG 1995 ↗	DE	502	0/0	unreachable	2026-10-30 12:44
§ 12 UStG ↗	DE	502	0/0	unreachable	2026-10-30 12:44
service-public.fr: barème 2026 (revenus 2025) ↗	FR	200	4/4	new	2026-10-30 12:44
entreprendre.service-public.fr: IS ↗	FR	200	3/3	new	2026-10-30 12:44
entreprendre.service-public.fr: TVA ↗	FR	200	1/1	new	2026-10-30 12:44
Belastingdienst: btw-tarieven ↗	NL	200	1/1	new	2026-10-30 12:44
Belastingdienst: table 1, 2026 ↗	NL	200	5/5	new	2026-10-30 12:44
Belastingdienst: minimum tax ↗	NL	200	0/1NL.P2.THRESHOLD	new	2026-10-30 12:44
Belastingdienst: Vpb tarieven ↗	NL	200	2/3NL.VPB.LOW	new	2026-10-30 12:44
Ley 35/2006, art. 57 (BOE consolidated) ↗	ES	200	1/1	new	2026-10-30 12:44
Agencia Tributaria: gravamen estatal ↗	ES	200	5/5	new	2026-10-30 12:44
Agencia Tributaria: tipo impositivo ↗	ES	200	1/1	new	2026-10-30 12:44
Agencia Tributaria: tipos impositivos ↗	ES	200	1/1	new	2026-10-30 12:44
Dipartimento Finanze: regional surcharge 2026 ↗	IT	200	1/1	new	2026-10-30 12:44
Dipartimento Finanze: IRAP 2026 ↗	IT	200	1/1	new	2026-10-30 12:44
Dipartimento Finanze: IRES ↗	IT	200	0/1	new	2026-10-30 12:44
MEF: main measures of the 2026 Budget Law ↗	IT	200	4/5IT.IRPEF.R1	new	2026-10-30 12:44
Dipartimento Finanze: IVA ↗	IT	200	0/1	new	2026-10-30 12:44

Golden checks

computed at build

Check	Expected	Computed	Result
Full allowance at £100,000UK.PA-1 · UK.IT.PA, UK.IT.PA.TAPER_START	12,570	12,570	pass
Allowance at £110,000 after the £1-per-£2 taperUK.PA-2 · UK.IT.PA.TAPER_START	7,570	7,570	pass
Allowance fully withdrawn at £125,140UK.PA-3 · UK.IT.PA.TAPER_START	0	0	pass
No tax at the personal allowance (£12,570)UK.IT-1 · UK.IT.PA	0	0	pass
Basic rate band fully used at £50,270UK.IT-2 · UK.IT.BRL × UK.IT.BR	7,540	7,540	pass
£85,000 salaryUK.IT-3 · 7,540 + 40% × 34,730	21,432	21,432	pass
£125,140, allowance exhaustedUK.IT-4 · 7,540 + 40% × 87,440	42,516	42,516	pass
£150,000 with additional rateUK.IT-5 · 42,516 + 45% × 24,860	53,703	53,703	pass
Effective 60% marginal rate between £100,000 and £110,000UK.IT-6 · Taper interaction	6,000	6,000	pass
Class 1 at the upper earnings limit (£50,270)UK.NI-1 · 8% × 37,700	3,016	3,016	pass
Class 1 on £85,000UK.NI-2 · 3,016 + 2% × 34,730	3,710.6	3,710.6	pass
Class 4 on £30,000 profitUK.NI-3 · 6% × 17,430	1,045.8	1,045.8	pass
Class 4 on £60,000 profitUK.NI-4 · 2,262 + 2% × 9,730	2,456.6	2,456.6	pass
Employer Class 1 on a £30,000 salaryUK.ER-1 · 15% × 25,000	3,750	3,750	pass
Nothing due at the £5,000 secondary thresholdUK.ER-2 · UK.NI.C1.ST	0	0	pass
£20,000 salary plus £5,000 dividends, 2025/26UK.DV-1 · 8.75% × 4,500	393.75	393.75	pass
Same case under 2026/27 ratesUK.DV-2 · 10.75% × 4,500	483.75	483.75	pass
£60,000 salary plus £10,000 dividends, 2025/26UK.DV-3 · 33.75% × 9,500	3,206.25	3,206.25	pass
£20,000 gain, £30,000 income (within basic band)UK.CG-1 · 18% × 17,000	3,060	3,060	pass
£20,000 gain, £60,000 incomeUK.CG-2 · 24% × 17,000	4,080	4,080	pass
Gain inside the annual exempt amountUK.CG-3 · UK.CGT.AEA	0	0	pass
Profit £50,000 at the small profits rateUK.CT-1 · 19% × 50,000	9,500	9,500	pass
Profit £100,000 with marginal reliefUK.CT-2 · 25,000 − 3/200 × 150,000	22,750	22,750	pass
Profit £250,000 at the main rateUK.CT-3 · 25% × 250,000	62,500	62,500	pass
£100,000 profit with two associated companies (limits ÷ 3) pays the main rateUK.CT-4 · Upper limit becomes £83,333	25,000	25,000	pass
Plan 2 repayment on £40,000UK.SL-1 · 9% × (40,000 − 29,385)	955.35	955.35	pass
Postgraduate loan on £30,000UK.SL-2 · 6% × 9,000	540	540	pass
Half the benefit charged at £70,000UK.CB-1 · 50 × 1% × 1,000	500	500	pass
Full benefit charged at £80,000UK.CB-2 · UK.HICBC.FULL	1,000	1,000	pass
Maximum saving £252 for a basic-rate recipientUK.MA-1 · 20% × 1,260	252	252	pass
Income tax on €50,000, single PAYE workerIE.IE-1 · 20% × 44,000 + 40% × 6,000 − 4,000 credits	7,200	7,200	pass
USC on €50,000IE.IE-2 · 60.06 + 333.76 + 639.00	1,032.82	1,032.82	pass
Tariff is continuous at the end of zone 1 (€17,799)DE.DE-1 · (914.51·y + 1 400)·y rounds down to 1,034	1,034	1,034	pass
Income tax on €50,000, no Solidaritätszuschlag below the exemption limitDE.DE-3 · (173.10·z + 2 397)·z + 1 034.87, z = 3.2201	10,548	10,548	pass
Corporate taxes on €100,000 at Hebesatz 400%DE.DE-4 · 15,000 + 825 + 14,000	29,825	29,825	pass
Impôt on €40,000 for one partFR.FR-1 · 11% × 17,979 + 30% × 10,421	5,103.99	5,103.99	pass
Two parts halve the per-part income (€40,000, 2 parts)FR.FR-2 · 2 × 11% × (20,000 − 11,600)	1,848	1,848	pass
IS on €100,000 for an eligible SMEFR.FR-3 · 15% × 42,500 + 25% × 57,500	20,750	20,750	pass
Box 1 before credits on €50,000NL.NL-1 · 35.75% × 38,883 + 37.56% × 11,117	18,076.22	18,076.22	pass
Vpb on €300,000NL.NL-2 · 19% × 200,000 + 25.8% × 100,000	63,800	63,800	pass
IRPF on a €30,000 base (state plus reference regional scale)ES.ES-1 · 2 × (3,582.75 − 527.25)	6,111	6,111	pass
Impuesto sobre Sociedades on €100,000ES.ES-2 · 25%	25,000	25,000	pass
IRPEF on €40,000 before the regional surchargeIT.IT-1 · 23% × 28,000 + 33% × 12,000	10,400	10,400	pass
IRES and IRAP on €100,000IT.IT-2 · 24% + 3.9%	27,900	27,900	pass

Property tests

computed at build

Property	Schedule · detail	Result
Liability never falls as the primary input risesuk.income_tax.monotonic	uk.income_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.income_tax.marginal_le_100	uk.income_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesuk.income_tax.continuity	uk.income_taxlargest 1-unit step 0.45 at 125250	pass
Identical inputs give identical proofsuk.income_tax.deterministic	uk.income_tax26 trace nodes	pass
Nothing is charged on nothinguk.income_tax.zero	uk.income_taxf(0) = 0	pass
Liability never falls as the primary input risesuk.ni.class1_employee.monotonic	uk.ni.class1_employee0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.ni.class1_employee.marginal_le_100	uk.ni.class1_employeemeasured over 200-unit windows	pass
No undocumented cliff edgesuk.ni.class1_employee.continuity	uk.ni.class1_employeelargest 1-unit step 0.08 at 16000	pass
Identical inputs give identical proofsuk.ni.class1_employee.deterministic	uk.ni.class1_employee12 trace nodes	pass
Nothing is charged on nothinguk.ni.class1_employee.zero	uk.ni.class1_employeef(0) = 0	pass
Liability never falls as the primary input risesuk.ni.class4.monotonic	uk.ni.class40 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.ni.class4.marginal_le_100	uk.ni.class4measured over 200-unit windows	pass
No undocumented cliff edgesuk.ni.class4.continuity	uk.ni.class4largest 1-unit step 0.06 at 21250	pass
Identical inputs give identical proofsuk.ni.class4.deterministic	uk.ni.class412 trace nodes	pass
Nothing is charged on nothinguk.ni.class4.zero	uk.ni.class4f(0) = 0	pass
Liability never falls as the primary input risesuk.dividend_tax.monotonic	uk.dividend_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.dividend_tax.marginal_le_100	uk.dividend_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesuk.dividend_tax.continuity	uk.dividend_taxlargest 1-unit step 0.00 at 0	pass
Identical inputs give identical proofsuk.dividend_tax.deterministic	uk.dividend_tax99 trace nodes	pass
Nothing is charged on nothinguk.dividend_tax.zero	uk.dividend_taxf(0) = 0	pass
Liability never falls as the primary input risesuk.capital_gains_tax.monotonic	uk.capital_gains_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.capital_gains_tax.marginal_le_100	uk.capital_gains_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesuk.capital_gains_tax.continuity	uk.capital_gains_taxlargest 1-unit step 0.24 at 285500	pass
Identical inputs give identical proofsuk.capital_gains_tax.deterministic	uk.capital_gains_tax27 trace nodes	pass
Nothing is charged on nothinguk.capital_gains_tax.zero	uk.capital_gains_taxf(0) = 0	pass
Liability never falls as the primary input risesuk.corporation_tax.monotonic	uk.corporation_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.corporation_tax.marginal_le_100	uk.corporation_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesuk.corporation_tax.continuity	uk.corporation_taxDocumented: Rounding to pence of relief and gross tax (largest 1-unit step 0.27 at 50000)	pass
Identical inputs give identical proofsuk.corporation_tax.deterministic	uk.corporation_tax40 trace nodes	pass
Nothing is charged on nothinguk.corporation_tax.zero	uk.corporation_taxf(0) = 0	pass
Liability never falls as the primary input risesuk.ni.class1_employer.monotonic	uk.ni.class1_employer0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.ni.class1_employer.marginal_le_100	uk.ni.class1_employermeasured over 200-unit windows	pass
No undocumented cliff edgesuk.ni.class1_employer.continuity	uk.ni.class1_employerlargest 1-unit step 0.15 at 114250	pass
Identical inputs give identical proofsuk.ni.class1_employer.deterministic	uk.ni.class1_employer25 trace nodes	pass
Nothing is charged on nothinguk.ni.class1_employer.zero	uk.ni.class1_employerf(0) = 0	pass
Liability never falls as the primary input risesuk.student_loan.monotonic	uk.student_loan0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.student_loan.marginal_le_100	uk.student_loanmeasured over 200-unit windows	pass
No undocumented cliff edgesuk.student_loan.continuity	uk.student_loanlargest 1-unit step 0.09 at 49750	pass
Identical inputs give identical proofsuk.student_loan.deterministic	uk.student_loan14 trace nodes	pass
Nothing is charged on nothinguk.student_loan.zero	uk.student_loanf(0) = 0	pass
Liability never falls as the primary input risesuk.child_benefit_charge.monotonic	uk.child_benefit_charge0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%uk.child_benefit_charge.marginal_le_100	uk.child_benefit_chargemeasured over 200-unit windows	pass
No undocumented cliff edgesuk.child_benefit_charge.continuity	uk.child_benefit_chargeDocumented: Charge rises in 1% steps per £200 by construction (largest 1-unit step 0.00 at 0)	pass
Identical inputs give identical proofsuk.child_benefit_charge.deterministic	uk.child_benefit_charge16 trace nodes	pass
Nothing is charged on nothinguk.child_benefit_charge.zero	uk.child_benefit_chargef(0) = 0	pass
Relief schedule (monotonicity not required)uk.marriage_allowance.monotonic	uk.marriage_allowanceskipped by nature	pass
Marginal rate never exceeds 100%uk.marriage_allowance.marginal_le_100	uk.marriage_allowancemeasured over 200-unit windows	pass
No undocumented cliff edgesuk.marriage_allowance.continuity	uk.marriage_allowancelargest 1-unit step 0.20 at 12750	pass
Identical inputs give identical proofsuk.marriage_allowance.deterministic	uk.marriage_allowance24 trace nodes	pass
Nothing is charged on nothinguk.marriage_allowance.zero	uk.marriage_allowancef(0) = 0	pass
Liability never falls as the primary input risesie.income_tax.monotonic	ie.income_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%ie.income_tax.marginal_le_100	ie.income_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesie.income_tax.continuity	ie.income_taxlargest 1-unit step 0.40 at 68000	pass
Identical inputs give identical proofsie.income_tax.deterministic	ie.income_tax28 trace nodes	pass
Nothing is charged on nothingie.income_tax.zero	ie.income_taxf(0) = 0	pass
Liability never falls as the primary input risesie.usc.monotonic	ie.usc0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%ie.usc.marginal_le_100	ie.uscmeasured over 200-unit windows	pass
No undocumented cliff edgesie.usc.continuity	ie.usclargest 1-unit step 0.08 at 254500	pass
Identical inputs give identical proofsie.usc.deterministic	ie.usc24 trace nodes	pass
Nothing is charged on nothingie.usc.zero	ie.uscf(0) = 0	pass
Liability never falls as the primary input risesde.income_tax.monotonic	de.income_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%de.income_tax.marginal_le_100	de.income_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesde.income_tax.continuity	de.income_taxDocumented: Einkommensteuer is rounded down to the full euro; Solidaritätszuschlag has a milder zone (largest 1-unit step 1.06 at 278500)	pass
Identical inputs give identical proofsde.income_tax.deterministic	de.income_tax46 trace nodes	pass
Nothing is charged on nothingde.income_tax.zero	de.income_taxf(0) = 0	pass
Liability never falls as the primary input risesde.corporate_taxes.monotonic	de.corporate_taxes0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%de.corporate_taxes.marginal_le_100	de.corporate_taxesmeasured over 200-unit windows	pass
No undocumented cliff edgesde.corporate_taxes.continuity	de.corporate_taxeslargest 1-unit step 0.16 at 207250	pass
Identical inputs give identical proofsde.corporate_taxes.deterministic	de.corporate_taxes22 trace nodes	pass
Nothing is charged on nothingde.corporate_taxes.zero	de.corporate_taxesf(0) = 0	pass
Liability never falls as the primary input risesfr.income_tax.monotonic	fr.income_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%fr.income_tax.marginal_le_100	fr.income_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesfr.income_tax.continuity	fr.income_taxlargest 1-unit step 0.00 at 0	pass
Identical inputs give identical proofsfr.income_tax.deterministic	fr.income_tax21 trace nodes	pass
Nothing is charged on nothingfr.income_tax.zero	fr.income_taxf(0) = 0	pass
Liability never falls as the primary input risesfr.corporate_tax.monotonic	fr.corporate_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%fr.corporate_tax.marginal_le_100	fr.corporate_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesfr.corporate_tax.continuity	fr.corporate_taxlargest 1-unit step 0.25 at 0	pass
Identical inputs give identical proofsfr.corporate_tax.deterministic	fr.corporate_tax23 trace nodes	pass
Nothing is charged on nothingfr.corporate_tax.zero	fr.corporate_taxf(0) = 0	pass
Liability never falls as the primary input risesnl.box1.monotonic	nl.box10 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%nl.box1.marginal_le_100	nl.box1measured over 200-unit windows	pass
No undocumented cliff edgesnl.box1.continuity	nl.box1largest 1-unit step 0.50 at 78500	pass
Identical inputs give identical proofsnl.box1.deterministic	nl.box112 trace nodes	pass
Nothing is charged on nothingnl.box1.zero	nl.box1f(0) = 0	pass
Liability never falls as the primary input risesnl.corporate_tax.monotonic	nl.corporate_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%nl.corporate_tax.marginal_le_100	nl.corporate_taxmeasured over 200-unit windows	pass
No undocumented cliff edgesnl.corporate_tax.continuity	nl.corporate_taxlargest 1-unit step 0.26 at 200000	pass
Identical inputs give identical proofsnl.corporate_tax.deterministic	nl.corporate_tax9 trace nodes	pass
Nothing is charged on nothingnl.corporate_tax.zero	nl.corporate_taxf(0) = 0	pass
Liability never falls as the primary input riseses.irpf.monotonic	es.irpf0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%es.irpf.marginal_le_100	es.irpfmeasured over 200-unit windows	pass
No undocumented cliff edgeses.irpf.continuity	es.irpflargest 1-unit step 0.50 at 300000	pass
Identical inputs give identical proofses.irpf.deterministic	es.irpf97 trace nodes	pass
Nothing is charged on nothinges.irpf.zero	es.irpff(0) = 0	pass
Liability never falls as the primary input riseses.corporate_tax.monotonic	es.corporate_tax0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%es.corporate_tax.marginal_le_100	es.corporate_taxmeasured over 200-unit windows	pass
No undocumented cliff edgeses.corporate_tax.continuity	es.corporate_taxlargest 1-unit step 0.25 at 0	pass
Identical inputs give identical proofses.corporate_tax.deterministic	es.corporate_tax5 trace nodes	pass
Nothing is charged on nothinges.corporate_tax.zero	es.corporate_taxf(0) = 0	pass
Liability never falls as the primary input risesit.irpef.monotonic	it.irpef0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%it.irpef.marginal_le_100	it.irpefmeasured over 200-unit windows	pass
No undocumented cliff edgesit.irpef.continuity	it.irpeflargest 1-unit step 0.43 at 50000	pass
Identical inputs give identical proofsit.irpef.deterministic	it.irpef19 trace nodes	pass
Nothing is charged on nothingit.irpef.zero	it.irpeff(0) = 0	pass
Liability never falls as the primary input risesit.corporate_taxes.monotonic	it.corporate_taxes0 to 300,000 in 500 steps	pass
Marginal rate never exceeds 100%it.corporate_taxes.marginal_le_100	it.corporate_taxesmeasured over 200-unit windows	pass
No undocumented cliff edgesit.corporate_taxes.continuity	it.corporate_taxeslargest 1-unit step 0.28 at 29500	pass
Identical inputs give identical proofsit.corporate_taxes.deterministic	it.corporate_taxes12 trace nodes	pass
Nothing is charged on nothingit.corporate_taxes.zero	it.corporate_taxesf(0) = 0	pass
Remuneration sweep never pays more than the profit can fundanalysis.remuneration.feasible	analysis5 profit levels, salary 0 to the affordable maximum	pass
Salary, employer NI, corporation tax, dividends and retention add back to profitanalysis.remuneration.conserved	analysiswithin 0.02 at every point	pass
A larger pension contribution never saves lessanalysis.pension.saved_monotonic	analysisincomes 30,000, 60,000 and 130,000	pass
Component marginal rates add to the total marginal rateanalysis.marginal.components_sum	analysis201 points	pass

Posture

built · measured · designed

Area	State	Detail
Determinism	built	Same inputs, parameters and engine version give the same bytes; every evaluation carries a replay hash.
Provenance	built	Each parameter has a source URL, effective dates, status and the date it was last confirmed; schedules cite the parameters they use.
Statute worked examples	built	Golden checks reproduce published worked examples and thresholds per pack and fail the build if they drift.
Property tests	built	Monotonicity for liabilities, marginal rate never above 100%, continuity except at known cliffs, zero at zero, determinism.
Independent oracle	built	A second, hand-written implementation of every schedule is run across a grid; divergences block release.
Grounded reports	built	Every figure in a report must match an engine or Library figure within 0.6%; citations must resolve; reports that fail are rejected, not softened.
Review gates	built	Cross-border, reserved-jurisdiction, institutional and large-figure reports are marked for review by a registered specialist before release.
Security headers and privacy	measured	Static export with strict headers, no third-party scripts or trackers; the API sets nosniff, no-referrer, HSTS and a deny-all CSP.
Model data handling	designed	Reports run on the Anthropic API with zero data retention requested for the organisation; batch processing is not used for client facts because it is not eligible for zero retention.
Filing and payments	designed	No filing or payment rail is live; both are specified to run from sealed records with explicit signature.

Authority sources

45 pages

UK · GOV.UK trading and property allowances ↗UK · GOV.UK CGT allowances ↗UK · GOV.UK CGT rates ↗UK · GOV.UK marginal relief ↗UK · GOV.UK Corporation Tax rates ↗UK · GOV.UK tax on dividends ↗UK · GOV.UK Income Tax rates and allowances, current and past ↗UK · GOV.UK Child Benefit tax charge ↗UK · GOV.UK Income Tax rates ↗UK · GOV.UK income over £100,000 ↗UK · GOV.UK Marriage Allowance ↗UK · GOV.UK MTD for Income Tax ↗UK · GOV.UK threshold reduction to £20,000 ↗UK · GOV.UK National Insurance rates ↗UK · GOV.UK self-employed NI rates ↗UK · GOV.UK Employment Allowance ↗UK · GOV.UK pension annual allowance ↗UK · GOV.UK student loan repayment ↗UK · GOV.UK VAT registration ↗IE · Revenue: basis of charge ↗IE · Revenue: tax rates, bands and reliefs ↗IE · Revenue: USC rates and thresholds 2026 ↗IE · Revenue: current VAT rates ↗DE · § 32a EStG (VZ 2026) ↗DE · § 11 GewStG ↗DE · § 23 KStG ↗DE · § 4 SolzG 1995 ↗DE · § 3 SolzG 1995 ↗DE · § 12 UStG ↗FR · service-public.fr: barème 2026 (revenus 2025) ↗FR · entreprendre.service-public.fr: IS ↗FR · entreprendre.service-public.fr: TVA ↗NL · Belastingdienst: btw-tarieven ↗NL · Belastingdienst: table 1, 2026 ↗NL · Belastingdienst: minimum tax ↗NL · Belastingdienst: Vpb tarieven ↗ES · Ley 35/2006, art. 57 (BOE consolidated) ↗ES · Agencia Tributaria: gravamen estatal ↗ES · Agencia Tributaria: tipo impositivo ↗ES · Agencia Tributaria: tipos impositivos ↗IT · Dipartimento Finanze: regional surcharge 2026 ↗IT · Dipartimento Finanze: IRAP 2026 ↗IT · Dipartimento Finanze: IRES ↗IT · MEF: main measures of the 2026 Budget Law ↗IT · Dipartimento Finanze: IVA ↗

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