diff --git a/revenue-usage-reconciliation/README.md b/revenue-usage-reconciliation/README.md
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+# Revenue Usage Reconciliation
+
+This module adds a focused revenue-ops validation layer for SCIBASE revenue infrastructure.
+It reconciles plan entitlements, compute usage, top-ups, invoice totals, and anonymized analytics licensing exports so reviewers can catch undercharges, overcharges, refund risk, and unsafe licensing exports before closing a billing cycle.
+
+It is intentionally dependency-free and can be run with stock Node.js.
+
+## What It Covers
+
+- Tiered plan quotas and included subscription charges.
+- AI compute usage meters by capability.
+- Top-up credit reconciliation before overage calculation.
+- Invoice comparison against expected charges.
+- Undercharge and overcharge anomaly detection.
+- Anonymized licensing export safety checks.
+- Revenue health reports with high-risk account lists and audit hashes.
+- Entitlement regression matrix for month-over-month review.
+
+## Demo
+
+```bash
+npm run demo
+```
+
+The demo prints a report with one clean lab account, one undercharged institutional account, and one unsafe licensing export.
+Text-only demo evidence is included in `docs/demo-transcript.md` for reviewers who prefer not to inspect the GIF.
+
+## Verification
+
+```bash
+npm run check
+npm test
+npm run demo
+```
+
+## Files
+
+- `src/reconciliation.js` - core reconciliation, anomaly, health report, and regression logic.
+- `test/reconciliation.test.js` - focused tests for clean billing, undercharges, licensing risk, aggregation, and regressions.
+- `scripts/demo.js` - CLI demo with sample subscription, usage, invoice, and licensing data.
+- `docs/issue-20-requirement-map.md` - mapping from issue requirements to implementation evidence.
+- `docs/demo-transcript.md` - text-only reviewer evidence for the demo scenario.
+
+## AI-Assisted Disclosure
+
+This contribution was produced with AI assistance and manually verified before submission.
diff --git a/revenue-usage-reconciliation/docs/demo-transcript.md b/revenue-usage-reconciliation/docs/demo-transcript.md
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+# Revenue Usage Reconciliation Demo Transcript
+
+This transcript gives reviewers a text-only demo artifact for issue #20 in addition to the GIF.
+
+## Command
+
+```bash
+npm run demo
+```
+
+## Expected Highlights
+
+- Report status is `needs-revenue-ops-review`.
+- Total expected revenue is `313000` cents.
+- Total actual invoice revenue is `309800` cents.
+- Delta is `-3200` cents.
+- Two anomalies are reported.
+- `institute-undercharged` is flagged for a medium-severity undercharge.
+- `agency-export-risk` is flagged for a high-severity unsafe licensing export.
+- The regression matrix keeps `lab-clean` clean and marks new risky accounts as review-required.
+
+## Reviewer Value
+
+The demo proves this module can catch revenue leakage, refund-risk style billing mismatches, and unsafe analytics licensing exports before a billing cycle is closed.
diff --git a/revenue-usage-reconciliation/docs/demo.gif b/revenue-usage-reconciliation/docs/demo.gif
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diff --git a/revenue-usage-reconciliation/docs/issue-20-requirement-map.md b/revenue-usage-reconciliation/docs/issue-20-requirement-map.md
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+# Issue #20 Requirement Map
+
+This module is a focused revenue operations slice for the SCIBASE revenue infrastructure bounty. It is not another payment provider mock; it verifies whether usage, entitlements, invoices, top-ups, and analytics licensing exports reconcile cleanly before the month is closed.
+
+| Issue #20 requirement | Implementation evidence |
+| --- | --- |
+| Tiered subscription billing | `normalizeAccount` models plan name, included quota, included price, and overage rate. |
+| Volume/top-up support | `expectedChargeCents` includes top-up credits before calculating overage units. |
+| AI compute usage billing | `summarizeUsage` aggregates billable and non-billable usage by capability. |
+| Transparent quotas and usage meters | `reconcileAccount` reports included units, billable units, overage units, expected charge, actual charge, and delta. |
+| Institutional invoicing | Invoice totals are compared against expected entitlement and usage charges. |
+| Licensing APIs and analytics | `inspectLicensingExports` checks that analytics exports are anonymized and do not expose private fields. |
+| Revenue health reporting | `buildRevenueHealthReport` summarizes total expected/actual revenue, anomaly counts, high-risk accounts, and an audit hash. |
+| Regression evidence | `buildEntitlementRegressionMatrix` flags accounts that moved from clean to review-required between billing runs. |
+
+## Reviewer Notes
+
+- Dependency-free Node.js implementation for easy review.
+- Designed as a revenue-ops validation layer that can sit beside existing billing or entitlement engines.
+- Demo output includes one clean lab account, one undercharged institution, and one unsafe analytics export.
diff --git a/revenue-usage-reconciliation/package.json b/revenue-usage-reconciliation/package.json
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+++ b/revenue-usage-reconciliation/package.json
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+{
+  "name": "revenue-usage-reconciliation",
+  "version": "1.0.0",
+  "description": "Usage anomaly reconciliation and entitlement regression reporting for SCIBASE revenue infrastructure.",
+  "main": "src/reconciliation.js",
+  "type": "commonjs",
+  "scripts": {
+    "check": "node --check src/reconciliation.js && node --check scripts/demo.js && node --check test/reconciliation.test.js",
+    "demo": "node scripts/demo.js",
+    "test": "node test/reconciliation.test.js"
+  },
+  "license": "Apache-2.0"
+}
diff --git a/revenue-usage-reconciliation/scripts/demo.js b/revenue-usage-reconciliation/scripts/demo.js
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+++ b/revenue-usage-reconciliation/scripts/demo.js
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+"use strict";
+
+const {
+  buildRevenueHealthReport,
+  buildEntitlementRegressionMatrix
+} = require("../src/reconciliation");
+
+const previousAccounts = [
+  {
+    id: "lab-clean",
+    plan: { name: "Lab Pro", monthlyQuotaUnits: 1000, includedCents: 9900, overageCentsPerUnit: 12 },
+    topUps: [{ id: "top-1", units: 200 }],
+    usageEvents: [{ capability: "ai-review", units: 900 }],
+    invoices: [{ id: "inv-1", amountCents: 9900 }],
+    licensingExports: [{ id: "lic-1", dataset: "topic-trends", anonymized: true, fields: ["topic", "score"] }]
+  }
+];
+
+const currentAccounts = [
+  {
+    id: "lab-clean",
+    plan: { name: "Lab Pro", monthlyQuotaUnits: 1000, includedCents: 9900, overageCentsPerUnit: 12 },
+    topUps: [{ id: "top-1", units: 200 }],
+    usageEvents: [{ capability: "ai-review", units: 900 }],
+    invoices: [{ id: "inv-1", amountCents: 9900 }],
+    licensingExports: [{ id: "lic-1", dataset: "topic-trends", anonymized: true, fields: ["topic", "score"] }]
+  },
+  {
+    id: "institute-undercharged",
+    plan: { name: "Institution", monthlyQuotaUnits: 5000, includedCents: 49900, overageCentsPerUnit: 8 },
+    topUps: [],
+    usageEvents: [
+      { capability: "reproducibility-run", units: 5400 },
+      { capability: "literature-scan", units: 200, billable: false }
+    ],
+    invoices: [{ id: "inv-2", amountCents: 49900 }],
+    licensingExports: [{ id: "lic-2", dataset: "reuse-map", anonymized: true, fields: ["topic", "method", "score"] }]
+  },
+  {
+    id: "agency-export-risk",
+    plan: { name: "Analytics License", monthlyQuotaUnits: 0, includedCents: 250000, overageCentsPerUnit: 0 },
+    topUps: [],
+    usageEvents: [],
+    invoices: [{ id: "inv-3", amountCents: 250000 }],
+    licensingExports: [{ id: "lic-3", dataset: "grant-impact", anonymized: false, fields: ["topic", "orcid", "raw_email"] }]
+  }
+];
+
+const previous = buildRevenueHealthReport(previousAccounts);
+const current = buildRevenueHealthReport(currentAccounts);
+const regression = buildEntitlementRegressionMatrix(previous, current);
+
+console.log(JSON.stringify({
+  report: {
+    status: current.status,
+    totals: current.totals,
+    highRiskAccounts: current.highRiskAccounts,
+    auditHash: current.auditHash
+  },
+  regression,
+  anomalies: current.reconciliations.flatMap((account) =>
+    account.anomalies.map((anomaly) => ({
+      accountId: account.accountId,
+      type: anomaly.type,
+      severity: anomaly.severity,
+      amountCents: anomaly.amountCents || 0
+    }))
+  )
+}, null, 2));
diff --git a/revenue-usage-reconciliation/src/reconciliation.js b/revenue-usage-reconciliation/src/reconciliation.js
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+++ b/revenue-usage-reconciliation/src/reconciliation.js
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+"use strict";
+
+const crypto = require("crypto");
+
+function money(cents) {
+  return Math.round(cents);
+}
+
+function hashPayload(value) {
+  return crypto.createHash("sha256").update(JSON.stringify(value)).digest("hex");
+}
+
+function normalizeAccount(account) {
+  if (!account || !account.id || !account.plan) {
+    throw new Error("account requires id and plan");
+  }
+
+  return {
+    id: account.id,
+    plan: {
+      name: account.plan.name,
+      monthlyQuotaUnits: account.plan.monthlyQuotaUnits || 0,
+      includedCents: money(account.plan.includedCents || 0),
+      overageCentsPerUnit: money(account.plan.overageCentsPerUnit || 0)
+    },
+    topUps: Array.isArray(account.topUps) ? account.topUps : [],
+    invoices: Array.isArray(account.invoices) ? account.invoices : [],
+    usageEvents: Array.isArray(account.usageEvents) ? account.usageEvents : [],
+    licensingExports: Array.isArray(account.licensingExports) ? account.licensingExports : []
+  };
+}
+
+function summarizeUsage(usageEvents) {
+  return usageEvents.reduce((summary, event) => {
+    const units = Number(event.units || 0);
+    summary.totalUnits += units;
+    summary.byCapability[event.capability] = (summary.byCapability[event.capability] || 0) + units;
+    if (event.billable === false) {
+      summary.nonBillableUnits += units;
+    }
+    return summary;
+  }, {
+    totalUnits: 0,
+    nonBillableUnits: 0,
+    byCapability: {}
+  });
+}
+
+function summarizeCredits(topUps) {
+  return topUps.reduce((total, topUp) => total + Number(topUp.units || 0), 0);
+}
+
+function expectedChargeCents(account, usageSummary) {
+  const includedUnits = account.plan.monthlyQuotaUnits + summarizeCredits(account.topUps);
+  const billableUnits = Math.max(0, usageSummary.totalUnits - usageSummary.nonBillableUnits);
+  const overageUnits = Math.max(0, billableUnits - includedUnits);
+  return {
+    includedUnits,
+    billableUnits,
+    overageUnits,
+    expectedCents: money(account.plan.includedCents + (overageUnits * account.plan.overageCentsPerUnit))
+  };
+}
+
+function actualInvoiceCents(invoices) {
+  return money(invoices.reduce((total, invoice) => total + Number(invoice.amountCents || 0), 0));
+}
+
+function inspectLicensingExports(exports) {
+  return exports.map((item) => {
+    const fields = Array.isArray(item.fields) ? item.fields : [];
+    const privateFields = fields.filter((field) => /email|name|orcid|private|raw/i.test(field));
+    return {
+      id: item.id,
+      dataset: item.dataset,
+      anonymized: item.anonymized === true,
+      privateFields,
+      safeForLicensing: item.anonymized === true && privateFields.length === 0
+    };
+  });
+}
+
+function reconcileAccount(accountInput) {
+  const account = normalizeAccount(accountInput);
+  const usageSummary = summarizeUsage(account.usageEvents);
+  const expected = expectedChargeCents(account, usageSummary);
+  const actualCents = actualInvoiceCents(account.invoices);
+  const deltaCents = money(actualCents - expected.expectedCents);
+  const licensing = inspectLicensingExports(account.licensingExports);
+  const anomalies = [];
+
+  if (deltaCents < 0) {
+    anomalies.push({
+      type: "undercharge",
+      severity: Math.abs(deltaCents) > 5000 ? "high" : "medium",
+      amountCents: Math.abs(deltaCents),
+      message: "Invoice total is lower than expected entitlement and overage charge."
+    });
+  }
+
+  if (deltaCents > 0) {
+    anomalies.push({
+      type: "overcharge",
+      severity: deltaCents > 5000 ? "high" : "medium",
+      amountCents: deltaCents,
+      message: "Invoice total is higher than expected entitlement and overage charge."
+    });
+  }
+
+  for (const exportCheck of licensing) {
+    if (!exportCheck.safeForLicensing) {
+      anomalies.push({
+        type: "licensing-export-risk",
+        severity: "high",
+        exportId: exportCheck.id,
+        message: "Licensing export is not safely anonymized for institutional analytics."
+      });
+    }
+  }
+
+  return {
+    accountId: account.id,
+    planName: account.plan.name,
+    usageSummary,
+    expected,
+    actualCents,
+    deltaCents,
+    licensing,
+    anomalies
+  };
+}
+
+function buildRevenueHealthReport(accounts) {
+  const reconciliations = accounts.map(reconcileAccount);
+  const totals = reconciliations.reduce((summary, item) => {
+    summary.expectedCents += item.expected.expectedCents;
+    summary.actualCents += item.actualCents;
+    summary.deltaCents += item.deltaCents;
+    summary.anomalyCount += item.anomalies.length;
+    return summary;
+  }, {
+    expectedCents: 0,
+    actualCents: 0,
+    deltaCents: 0,
+    anomalyCount: 0
+  });
+
+  const highRiskAccounts = reconciliations
+    .filter((item) => item.anomalies.some((anomaly) => anomaly.severity === "high"))
+    .map((item) => item.accountId);
+
+  return {
+    status: totals.anomalyCount === 0 ? "ready-for-close" : "needs-revenue-ops-review",
+    totals,
+    highRiskAccounts,
+    reconciliations,
+    auditHash: hashPayload(reconciliations)
+  };
+}
+
+function buildEntitlementRegressionMatrix(previousReport, currentReport) {
+  const previousByAccount = new Map(previousReport.reconciliations.map((item) => [item.accountId, item]));
+  return currentReport.reconciliations.map((current) => {
+    const previous = previousByAccount.get(current.accountId);
+    const previousStatus = previous
+      ? (previous.anomalies.length === 0 ? "clean" : "review")
+      : "new-account";
+    const currentStatus = current.anomalies.length === 0 ? "clean" : "review";
+    return {
+      accountId: current.accountId,
+      previousStatus,
+      currentStatus,
+      regressed: previousStatus === "clean" && currentStatus === "review",
+      deltaCents: current.deltaCents - (previous ? previous.deltaCents : 0)
+    };
+  });
+}
+
+module.exports = {
+  normalizeAccount,
+  summarizeUsage,
+  reconcileAccount,
+  buildRevenueHealthReport,
+  buildEntitlementRegressionMatrix
+};
diff --git a/revenue-usage-reconciliation/test/reconciliation.test.js b/revenue-usage-reconciliation/test/reconciliation.test.js
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+"use strict";
+
+const assert = require("assert");
+const {
+  reconcileAccount,
+  buildRevenueHealthReport,
+  buildEntitlementRegressionMatrix
+} = require("../src/reconciliation");
+
+function cleanAccount() {
+  return {
+    id: "lab-clean",
+    plan: { name: "Lab Pro", monthlyQuotaUnits: 100, includedCents: 10000, overageCentsPerUnit: 25 },
+    topUps: [{ units: 50 }],
+    usageEvents: [
+      { capability: "ai-review", units: 125 },
+      { capability: "literature-scan", units: 25 }
+    ],
+    invoices: [{ amountCents: 10000 }],
+    licensingExports: [{ id: "lic-1", dataset: "topic-trends", anonymized: true, fields: ["topic", "score"] }]
+  };
+}
+
+function testCleanAccountHasNoAnomalies() {
+  const result = reconcileAccount(cleanAccount());
+  assert.strictEqual(result.expected.expectedCents, 10000);
+  assert.strictEqual(result.deltaCents, 0);
+  assert.deepStrictEqual(result.anomalies, []);
+}
+
+function testUnderchargeDetectedForOverQuotaUsage() {
+  const account = cleanAccount();
+  account.usageEvents.push({ capability: "reproducibility-run", units: 20 });
+  const result = reconcileAccount(account);
+  assert.strictEqual(result.expected.overageUnits, 20);
+  assert.strictEqual(result.anomalies[0].type, "undercharge");
+  assert.strictEqual(result.anomalies[0].amountCents, 500);
+}
+
+function testOverchargeDetectedForRefundRisk() {
+  const account = cleanAccount();
+  account.invoices = [{ amountCents: 11250 }];
+  const result = reconcileAccount(account);
+  assert.strictEqual(result.deltaCents, 1250);
+  assert.strictEqual(result.anomalies[0].type, "overcharge");
+  assert.strictEqual(result.anomalies[0].amountCents, 1250);
+}
+
+function testLicensingExportRiskDetected() {
+  const account = cleanAccount();
+  account.licensingExports = [{ id: "lic-risk", dataset: "grant-map", anonymized: false, fields: ["orcid", "raw_email"] }];
+  const result = reconcileAccount(account);
+  assert.strictEqual(result.anomalies[0].type, "licensing-export-risk");
+  assert.strictEqual(result.licensing[0].safeForLicensing, false);
+}
+
+function testRevenueHealthReportAggregatesRisk() {
+  const risky = cleanAccount();
+  risky.id = "risky";
+  risky.invoices = [{ amountCents: 20000 }];
+  const report = buildRevenueHealthReport([cleanAccount(), risky]);
+  assert.strictEqual(report.status, "needs-revenue-ops-review");
+  assert.strictEqual(report.totals.anomalyCount, 1);
+  assert.deepStrictEqual(report.highRiskAccounts, ["risky"]);
+  assert.ok(report.auditHash.length >= 32);
+}
+
+function testEntitlementRegressionMatrixFlagsNewReviewState() {
+  const previous = buildRevenueHealthReport([cleanAccount()]);
+  const currentAccount = cleanAccount();
+  currentAccount.invoices = [{ amountCents: 8000 }];
+  const current = buildRevenueHealthReport([currentAccount]);
+  const matrix = buildEntitlementRegressionMatrix(previous, current);
+  assert.strictEqual(matrix[0].previousStatus, "clean");
+  assert.strictEqual(matrix[0].currentStatus, "review");
+  assert.strictEqual(matrix[0].regressed, true);
+}
+
+function testEntitlementRegressionMatrixMarksNewAccounts() {
+  const previous = buildRevenueHealthReport([]);
+  const current = buildRevenueHealthReport([cleanAccount()]);
+  const matrix = buildEntitlementRegressionMatrix(previous, current);
+  assert.strictEqual(matrix[0].previousStatus, "new-account");
+  assert.strictEqual(matrix[0].currentStatus, "clean");
+}
+
+const tests = [
+  testCleanAccountHasNoAnomalies,
+  testUnderchargeDetectedForOverQuotaUsage,
+  testOverchargeDetectedForRefundRisk,
+  testLicensingExportRiskDetected,
+  testRevenueHealthReportAggregatesRisk,
+  testEntitlementRegressionMatrixFlagsNewReviewState,
+  testEntitlementRegressionMatrixMarksNewAccounts
+];
+
+for (const test of tests) {
+  test();
+}
+
+console.log(`${tests.length} revenue reconciliation tests passed`);