diff --git a/enterprise-cost-center-chargeback-guard/README.md b/enterprise-cost-center-chargeback-guard/README.md
new file mode 100644
index 00000000..bd4d4ada
--- /dev/null
+++ b/enterprise-cost-center-chargeback-guard/README.md
@@ -0,0 +1,25 @@
+# Enterprise cost center chargeback guard
+
+This module checks whether institutional compute or service usage can be posted back to a department cost center.
+
+It focuses on one enterprise tooling slice: chargeback readiness. It does not process payments, move money, call finance systems, or store credentials.
+
+## What it checks
+
+- active cost center
+- PI approval
+- grant allowability
+- expense category rules
+- remaining budget and overage approval
+- usage evidence
+- data residency
+- purchase order and tax code gaps
+
+## Run it
+
+```bash
+node enterprise-cost-center-chargeback-guard/test.js
+node enterprise-cost-center-chargeback-guard/demo.js
+```
+
+The demo writes a JSON result and Markdown report to `artifacts/`.
diff --git a/enterprise-cost-center-chargeback-guard/artifacts/chargeback-report.md b/enterprise-cost-center-chargeback-guard/artifacts/chargeback-report.md
new file mode 100644
index 00000000..57c86d73
--- /dev/null
+++ b/enterprise-cost-center-chargeback-guard/artifacts/chargeback-report.md
@@ -0,0 +1,28 @@
+# Enterprise cost center chargeback report
+
+## CB-1001: Neuroscience lab
+Amount: 4200
+Decision: APPROVE_CHARGEBACK
+Next step: post the chargeback to the institution ledger
+
+## CB-1002: Materials group
+Amount: 9600
+Decision: ROUTE_FOR_APPROVAL
+Next step: send to finance for a manual approval pass
+Warnings:
+- charge exceeds remaining budget but has overage approval
+- no purchase order attached
+
+## CB-1003: Clinical data unit
+Amount: 3100
+Decision: BLOCK_CHARGEBACK
+Next step: do not post until blockers are fixed
+Blockers:
+- inactive cost center
+- missing PI approval
+- expense category not allowed
+- missing usage evidence
+- data residency mismatch
+Warnings:
+- no purchase order attached
+- missing tax code
diff --git a/enterprise-cost-center-chargeback-guard/artifacts/chargeback-results.json b/enterprise-cost-center-chargeback-guard/artifacts/chargeback-results.json
new file mode 100644
index 00000000..62450284
--- /dev/null
+++ b/enterprise-cost-center-chargeback-guard/artifacts/chargeback-results.json
@@ -0,0 +1,41 @@
+[
+  {
+    "recordId": "CB-1001",
+    "department": "Neuroscience lab",
+    "amount": 4200,
+    "decision": "APPROVE_CHARGEBACK",
+    "blockers": [],
+    "warnings": [],
+    "nextStep": "post the chargeback to the institution ledger"
+  },
+  {
+    "recordId": "CB-1002",
+    "department": "Materials group",
+    "amount": 9600,
+    "decision": "ROUTE_FOR_APPROVAL",
+    "blockers": [],
+    "warnings": [
+      "charge exceeds remaining budget but has overage approval",
+      "no purchase order attached"
+    ],
+    "nextStep": "send to finance for a manual approval pass"
+  },
+  {
+    "recordId": "CB-1003",
+    "department": "Clinical data unit",
+    "amount": 3100,
+    "decision": "BLOCK_CHARGEBACK",
+    "blockers": [
+      "inactive cost center",
+      "missing PI approval",
+      "expense category not allowed",
+      "missing usage evidence",
+      "data residency mismatch"
+    ],
+    "warnings": [
+      "no purchase order attached",
+      "missing tax code"
+    ],
+    "nextStep": "do not post until blockers are fixed"
+  }
+]
\ No newline at end of file
diff --git a/enterprise-cost-center-chargeback-guard/artifacts/demo.gif b/enterprise-cost-center-chargeback-guard/artifacts/demo.gif
new file mode 100644
index 00000000..bf2efbb8
Binary files /dev/null and b/enterprise-cost-center-chargeback-guard/artifacts/demo.gif differ
diff --git a/enterprise-cost-center-chargeback-guard/artifacts/demo.mp4 b/enterprise-cost-center-chargeback-guard/artifacts/demo.mp4
new file mode 100644
index 00000000..62baa3ff
Binary files /dev/null and b/enterprise-cost-center-chargeback-guard/artifacts/demo.mp4 differ
diff --git a/enterprise-cost-center-chargeback-guard/demo.js b/enterprise-cost-center-chargeback-guard/demo.js
new file mode 100644
index 00000000..0cc0315e
--- /dev/null
+++ b/enterprise-cost-center-chargeback-guard/demo.js
@@ -0,0 +1,13 @@
+const fs = require("fs");
+const path = require("path");
+const records = require("./sample-data.json");
+const { evaluateChargebacks, renderMarkdownReport } = require("./index");
+
+const artifactsDir = path.join(__dirname, "artifacts");
+fs.mkdirSync(artifactsDir, { recursive: true });
+
+const results = evaluateChargebacks(records);
+fs.writeFileSync(path.join(artifactsDir, "chargeback-results.json"), JSON.stringify(results, null, 2));
+fs.writeFileSync(path.join(artifactsDir, "chargeback-report.md"), renderMarkdownReport(results));
+
+console.log(renderMarkdownReport(results));
diff --git a/enterprise-cost-center-chargeback-guard/index.js b/enterprise-cost-center-chargeback-guard/index.js
new file mode 100644
index 00000000..f69eabb2
--- /dev/null
+++ b/enterprise-cost-center-chargeback-guard/index.js
@@ -0,0 +1,74 @@
+function evaluateChargeback(record) {
+  const blockers = [];
+  const warnings = [];
+
+  if (!record.costCenterActive) blockers.push("inactive cost center");
+  if (!record.piApproval) blockers.push("missing PI approval");
+  if (!record.grantAllowsCharge) blockers.push("grant does not allow this charge");
+  if (!record.categoryAllowed) blockers.push("expense category not allowed");
+  if (!record.projectActive) blockers.push("project is not active");
+  if (!record.usageEvidence) blockers.push("missing usage evidence");
+  if (!record.dataResidencyOk) blockers.push("data residency mismatch");
+
+  if (record.amount > record.remainingBudget && !record.overageApproval) {
+    blockers.push("charge exceeds remaining budget without overage approval");
+  } else if (record.amount > record.remainingBudget) {
+    warnings.push("charge exceeds remaining budget but has overage approval");
+  }
+
+  if (!record.purchaseOrder) warnings.push("no purchase order attached");
+  if (!record.taxCode) warnings.push("missing tax code");
+
+  let decision = "APPROVE_CHARGEBACK";
+  if (blockers.length) {
+    decision = "BLOCK_CHARGEBACK";
+  } else if (warnings.length) {
+    decision = "ROUTE_FOR_APPROVAL";
+  }
+
+  return {
+    recordId: record.id,
+    department: record.department,
+    amount: record.amount,
+    decision,
+    blockers,
+    warnings,
+    nextStep: nextStepFor(decision),
+  };
+}
+
+function nextStepFor(decision) {
+  if (decision === "APPROVE_CHARGEBACK") return "post the chargeback to the institution ledger";
+  if (decision === "ROUTE_FOR_APPROVAL") return "send to finance for a manual approval pass";
+  return "do not post until blockers are fixed";
+}
+
+function evaluateChargebacks(records) {
+  return records.map(evaluateChargeback);
+}
+
+function renderMarkdownReport(results) {
+  const lines = ["# Enterprise cost center chargeback report", ""];
+  for (const result of results) {
+    lines.push(`## ${result.recordId}: ${result.department}`);
+    lines.push(`Amount: ${result.amount}`);
+    lines.push(`Decision: ${result.decision}`);
+    lines.push(`Next step: ${result.nextStep}`);
+    if (result.blockers.length) {
+      lines.push("Blockers:");
+      for (const blocker of result.blockers) lines.push(`- ${blocker}`);
+    }
+    if (result.warnings.length) {
+      lines.push("Warnings:");
+      for (const warning of result.warnings) lines.push(`- ${warning}`);
+    }
+    lines.push("");
+  }
+  return lines.join("\n");
+}
+
+module.exports = {
+  evaluateChargeback,
+  evaluateChargebacks,
+  renderMarkdownReport,
+};
diff --git a/enterprise-cost-center-chargeback-guard/sample-data.json b/enterprise-cost-center-chargeback-guard/sample-data.json
new file mode 100644
index 00000000..3607038a
--- /dev/null
+++ b/enterprise-cost-center-chargeback-guard/sample-data.json
@@ -0,0 +1,50 @@
+[
+  {
+    "id": "CB-1001",
+    "department": "Neuroscience lab",
+    "amount": 4200,
+    "remainingBudget": 12000,
+    "costCenterActive": true,
+    "piApproval": true,
+    "grantAllowsCharge": true,
+    "categoryAllowed": true,
+    "projectActive": true,
+    "usageEvidence": true,
+    "dataResidencyOk": true,
+    "overageApproval": false,
+    "purchaseOrder": "PO-4451",
+    "taxCode": "RND-SVC"
+  },
+  {
+    "id": "CB-1002",
+    "department": "Materials group",
+    "amount": 9600,
+    "remainingBudget": 8000,
+    "costCenterActive": true,
+    "piApproval": true,
+    "grantAllowsCharge": true,
+    "categoryAllowed": true,
+    "projectActive": true,
+    "usageEvidence": true,
+    "dataResidencyOk": true,
+    "overageApproval": true,
+    "purchaseOrder": "",
+    "taxCode": "RND-COMPUTE"
+  },
+  {
+    "id": "CB-1003",
+    "department": "Clinical data unit",
+    "amount": 3100,
+    "remainingBudget": 7000,
+    "costCenterActive": false,
+    "piApproval": false,
+    "grantAllowsCharge": true,
+    "categoryAllowed": false,
+    "projectActive": true,
+    "usageEvidence": false,
+    "dataResidencyOk": false,
+    "overageApproval": false,
+    "purchaseOrder": "",
+    "taxCode": ""
+  }
+]
diff --git a/enterprise-cost-center-chargeback-guard/test.js b/enterprise-cost-center-chargeback-guard/test.js
new file mode 100644
index 00000000..0a616416
--- /dev/null
+++ b/enterprise-cost-center-chargeback-guard/test.js
@@ -0,0 +1,19 @@
+const assert = require("assert");
+const records = require("./sample-data.json");
+const { evaluateChargebacks } = require("./index");
+
+const results = evaluateChargebacks(records);
+const byId = Object.fromEntries(results.map((result) => [result.recordId, result]));
+
+assert.strictEqual(byId["CB-1001"].decision, "APPROVE_CHARGEBACK");
+assert.strictEqual(byId["CB-1001"].blockers.length, 0);
+
+assert.strictEqual(byId["CB-1002"].decision, "ROUTE_FOR_APPROVAL");
+assert.ok(byId["CB-1002"].warnings.some((warning) => warning.includes("overage approval")));
+assert.ok(byId["CB-1002"].warnings.some((warning) => warning.includes("purchase order")));
+
+assert.strictEqual(byId["CB-1003"].decision, "BLOCK_CHARGEBACK");
+assert.ok(byId["CB-1003"].blockers.some((blocker) => blocker.includes("inactive cost center")));
+assert.ok(byId["CB-1003"].blockers.some((blocker) => blocker.includes("data residency")));
+
+console.log("enterprise cost center chargeback guard tests passed");