diff --git a/collaborative-footnote-export-guard/README.md b/collaborative-footnote-export-guard/README.md
new file mode 100644
index 00000000..d2df1991
--- /dev/null
+++ b/collaborative-footnote-export-guard/README.md
@@ -0,0 +1,36 @@
+# Collaborative Footnote Export Guard
+
+This module is a focused slice for the real-time collaborative research editor
+described in issue #12. It checks whether footnotes and endnotes are safe to
+include in a manuscript export after collaborative editing.
+
+The guard is intentionally dependency-free and uses synthetic data only. It
+does not call journal, payment, identity, storage, or external citation systems.
+
+## What It Checks
+
+- Orphaned manuscript footnote markers with no matching note text.
+- Duplicate note markers that would collapse during Markdown, LaTeX, or EndNote
+ export.
+- Private reviewer or collaborator notes that should not leave the editor.
+- Notes changed inside locked or final-review sections.
+- Missing citation bindings for source-backed notes.
+- Journal export order mismatches where endnotes must follow first appearance.
+
+## Local Verification
+
+```bash
+node collaborative-footnote-export-guard/test.js
+node collaborative-footnote-export-guard/demo.js
+```
+
+The demo writes reviewer-ready artifacts to
+`collaborative-footnote-export-guard/reports/`.
+
+## Issue #12 Mapping
+
+This complements the collaborative editor requirements for scientific formatting,
+cross-referencing, version history, section locks, comments/suggestions, and
+publication export readiness without overlapping broader editor, reference merge,
+figure/table, equation anchor, clipboard import, journal-style, or private
+comment export slices.
diff --git a/collaborative-footnote-export-guard/demo.js b/collaborative-footnote-export-guard/demo.js
new file mode 100644
index 00000000..aa6d3a97
--- /dev/null
+++ b/collaborative-footnote-export-guard/demo.js
@@ -0,0 +1,16 @@
+const fs = require("fs");
+const path = require("path");
+const { evaluateFootnoteExport, toMarkdownReport, toSvgBadge } = require("./footnoteExportGuard");
+const sampleWorkspace = require("./sampleWorkspace");
+
+const result = evaluateFootnoteExport(sampleWorkspace);
+const reportDir = path.join(__dirname, "reports");
+
+fs.mkdirSync(reportDir, { recursive: true });
+fs.writeFileSync(path.join(reportDir, "footnote-export-packet.json"), `${JSON.stringify(result, null, 2)}\n`);
+fs.writeFileSync(path.join(reportDir, "footnote-export-report.md"), toMarkdownReport(result));
+fs.writeFileSync(path.join(reportDir, "summary.svg"), toSvgBadge(result));
+
+console.log(`decision=${result.decision}`);
+console.log(`findings=${result.findings.length}`);
+console.log(`reports=${reportDir}`);
diff --git a/collaborative-footnote-export-guard/footnoteExportGuard.js b/collaborative-footnote-export-guard/footnoteExportGuard.js
new file mode 100644
index 00000000..92c9f7db
--- /dev/null
+++ b/collaborative-footnote-export-guard/footnoteExportGuard.js
@@ -0,0 +1,210 @@
+const DEFAULT_JOURNAL_POLICY = Object.freeze({
+ requireCitationBindings: true,
+ requireEndnoteOrder: true,
+ allowPrivateNotesInExport: false,
+ lockedSectionsBlockNoteEdits: true
+});
+
+function normalizePolicy(policy = {}) {
+ return { ...DEFAULT_JOURNAL_POLICY, ...policy };
+}
+
+function markerId(marker) {
+ if (typeof marker === "string") {
+ return marker.trim();
+ }
+ return marker && typeof marker.id === "string" ? marker.id.trim() : "";
+}
+
+function sectionById(sections) {
+ return new Map((sections || []).map((section) => [section.id, section]));
+}
+
+function firstAppearanceOrder(sections) {
+ const seen = new Map();
+
+ for (const section of sections || []) {
+ for (const marker of section.markers || []) {
+ const id = markerId(marker);
+ if (id && !seen.has(id)) {
+ seen.set(id, seen.size + 1);
+ }
+ }
+ }
+
+ return seen;
+}
+
+function buildDuplicateMarkerFindings(sections) {
+ const locations = new Map();
+
+ for (const section of sections || []) {
+ for (const marker of section.markers || []) {
+ const id = markerId(marker);
+ if (!id) {
+ continue;
+ }
+ const sectionLocations = locations.get(id) || [];
+ sectionLocations.push(section.id);
+ locations.set(id, sectionLocations);
+ }
+ }
+
+ return [...locations.entries()]
+ .filter(([, sectionIds]) => sectionIds.length > 1)
+ .map(([id, sectionIds]) => ({
+ id: `duplicate-marker:${id}`,
+ severity: "hold",
+ message: `Footnote marker ${id} appears in multiple manuscript sections.`,
+ evidence: { marker: id, sectionIds },
+ action: "Assign unique note markers or confirm that repeated references use an explicit shared-note alias."
+ }));
+}
+
+function evaluateFootnoteExport(workspace, policyInput = {}) {
+ const policy = normalizePolicy(policyInput);
+ const sections = workspace.sections || [];
+ const notes = workspace.notes || [];
+ const sectionsById = sectionById(sections);
+ const markerOrder = firstAppearanceOrder(sections);
+ const noteById = new Map(notes.map((note) => [note.id, note]));
+ const findings = [];
+
+ for (const marker of markerOrder.keys()) {
+ if (!noteById.has(marker)) {
+ findings.push({
+ id: `orphan-marker:${marker}`,
+ severity: "block",
+ message: `Marker ${marker} is present in the manuscript without matching note text.`,
+ evidence: { marker },
+ action: "Add the missing note text or remove the marker before export."
+ });
+ }
+ }
+
+ for (const note of notes) {
+ if (!markerOrder.has(note.id)) {
+ findings.push({
+ id: `unused-note:${note.id}`,
+ severity: "warn",
+ message: `Note ${note.id} has text but no visible manuscript marker.`,
+ evidence: { noteId: note.id },
+ action: "Either insert the marker in the manuscript or exclude the unused note from export."
+ });
+ }
+
+ if (!policy.allowPrivateNotesInExport && note.visibility === "private") {
+ findings.push({
+ id: `private-note:${note.id}`,
+ severity: "block",
+ message: `Private note ${note.id} would be included in the export packet.`,
+ evidence: { noteId: note.id, owner: note.owner, visibility: note.visibility },
+ action: "Redact the note or convert it to an export-safe public note after review."
+ });
+ }
+
+ if (policy.requireCitationBindings && note.requiresCitation && !note.citationKey) {
+ findings.push({
+ id: `missing-citation:${note.id}`,
+ severity: "hold",
+ message: `Source-backed note ${note.id} is missing a citation binding.`,
+ evidence: { noteId: note.id },
+ action: "Bind the note to an approved bibliography entry before export."
+ });
+ }
+
+ const section = sectionsById.get(note.sectionId);
+ if (policy.lockedSectionsBlockNoteEdits && section && section.locked && note.modifiedAfterLock) {
+ findings.push({
+ id: `locked-section-note-edit:${note.id}`,
+ severity: "block",
+ message: `Note ${note.id} changed after section ${section.id} entered final-review lock.`,
+ evidence: { noteId: note.id, sectionId: section.id, lockReason: section.lockReason },
+ action: "Ask the section owner to unlock, approve, or roll back the note edit."
+ });
+ }
+ }
+
+ findings.push(...buildDuplicateMarkerFindings(sections));
+
+ if (policy.requireEndnoteOrder) {
+ const exportableNotes = notes
+ .filter((note) => markerOrder.has(note.id))
+ .map((note) => ({ id: note.id, expectedOrder: markerOrder.get(note.id), exportedOrder: note.exportedOrder }));
+
+ for (const note of exportableNotes) {
+ if (note.exportedOrder !== note.expectedOrder) {
+ findings.push({
+ id: `endnote-order:${note.id}`,
+ severity: "hold",
+ message: `Endnote ${note.id} is exported as ${note.exportedOrder}, but first appears at position ${note.expectedOrder}.`,
+ evidence: note,
+ action: "Rebuild the endnote list from first marker appearance before journal export."
+ });
+ }
+ }
+ }
+
+ const blockers = findings.filter((finding) => finding.severity === "block");
+ const holds = findings.filter((finding) => finding.severity === "hold");
+ const warnings = findings.filter((finding) => finding.severity === "warn");
+ const decision = blockers.length > 0 ? "block-export" : holds.length > 0 ? "hold-for-editor-review" : "ready-for-export";
+
+ return {
+ workspaceId: workspace.id,
+ checkedAt: workspace.checkedAt || new Date().toISOString(),
+ decision,
+ summary: {
+ sections: sections.length,
+ notes: notes.length,
+ markers: markerOrder.size,
+ blockers: blockers.length,
+ holds: holds.length,
+ warnings: warnings.length
+ },
+ findings
+ };
+}
+
+function toMarkdownReport(result) {
+ const lines = [
+ `# Footnote Export Guard Report`,
+ ``,
+ `Workspace: ${result.workspaceId}`,
+ `Decision: ${result.decision}`,
+ ``,
+ `| Severity | Finding | Action |`,
+ `| --- | --- | --- |`
+ ];
+
+ for (const finding of result.findings) {
+ lines.push(`| ${finding.severity} | ${finding.message} | ${finding.action} |`);
+ }
+
+ if (result.findings.length === 0) {
+ lines.push(`| ok | No export-blocking footnote issues found. | Export may continue. |`);
+ }
+
+ return `${lines.join("\n")}\n`;
+}
+
+function toSvgBadge(result) {
+ const color = result.decision === "ready-for-export" ? "#0f7b45" : result.decision === "hold-for-editor-review" ? "#9a6700" : "#b42318";
+ const label = result.decision.replaceAll("-", " ");
+ return [
+ ``
+ ].join("\n");
+}
+
+module.exports = {
+ evaluateFootnoteExport,
+ toMarkdownReport,
+ toSvgBadge
+};
diff --git a/collaborative-footnote-export-guard/reports/demo.webm b/collaborative-footnote-export-guard/reports/demo.webm
new file mode 100644
index 00000000..df007ff3
Binary files /dev/null and b/collaborative-footnote-export-guard/reports/demo.webm differ
diff --git a/collaborative-footnote-export-guard/reports/footnote-export-packet.json b/collaborative-footnote-export-guard/reports/footnote-export-packet.json
new file mode 100644
index 00000000..b779bd30
--- /dev/null
+++ b/collaborative-footnote-export-guard/reports/footnote-export-packet.json
@@ -0,0 +1,99 @@
+{
+ "workspaceId": "editor-room-ms-042",
+ "checkedAt": "2026-05-30T19:30:00.000Z",
+ "decision": "block-export",
+ "summary": {
+ "sections": 3,
+ "notes": 4,
+ "markers": 4,
+ "blockers": 3,
+ "holds": 4,
+ "warnings": 1
+ },
+ "findings": [
+ {
+ "id": "orphan-marker:fn-5",
+ "severity": "block",
+ "message": "Marker fn-5 is present in the manuscript without matching note text.",
+ "evidence": {
+ "marker": "fn-5"
+ },
+ "action": "Add the missing note text or remove the marker before export."
+ },
+ {
+ "id": "private-note:fn-2",
+ "severity": "block",
+ "message": "Private note fn-2 would be included in the export packet.",
+ "evidence": {
+ "noteId": "fn-2",
+ "owner": "reviewer-7",
+ "visibility": "private"
+ },
+ "action": "Redact the note or convert it to an export-safe public note after review."
+ },
+ {
+ "id": "locked-section-note-edit:fn-2",
+ "severity": "block",
+ "message": "Note fn-2 changed after section methods entered final-review lock.",
+ "evidence": {
+ "noteId": "fn-2",
+ "sectionId": "methods",
+ "lockReason": "final-review"
+ },
+ "action": "Ask the section owner to unlock, approve, or roll back the note edit."
+ },
+ {
+ "id": "missing-citation:fn-3",
+ "severity": "hold",
+ "message": "Source-backed note fn-3 is missing a citation binding.",
+ "evidence": {
+ "noteId": "fn-3"
+ },
+ "action": "Bind the note to an approved bibliography entry before export."
+ },
+ {
+ "id": "unused-note:fn-4",
+ "severity": "warn",
+ "message": "Note fn-4 has text but no visible manuscript marker.",
+ "evidence": {
+ "noteId": "fn-4"
+ },
+ "action": "Either insert the marker in the manuscript or exclude the unused note from export."
+ },
+ {
+ "id": "duplicate-marker:fn-2",
+ "severity": "hold",
+ "message": "Footnote marker fn-2 appears in multiple manuscript sections.",
+ "evidence": {
+ "marker": "fn-2",
+ "sectionIds": [
+ "methods",
+ "results"
+ ]
+ },
+ "action": "Assign unique note markers or confirm that repeated references use an explicit shared-note alias."
+ },
+ {
+ "id": "endnote-order:fn-2",
+ "severity": "hold",
+ "message": "Endnote fn-2 is exported as 3, but first appears at position 2.",
+ "evidence": {
+ "id": "fn-2",
+ "expectedOrder": 2,
+ "exportedOrder": 3
+ },
+ "action": "Rebuild the endnote list from first marker appearance before journal export."
+ },
+ {
+ "id": "endnote-order:fn-3",
+ "severity": "hold",
+ "message": "Endnote fn-3 is exported as 2, but first appears at position 3.",
+ "evidence": {
+ "id": "fn-3",
+ "expectedOrder": 3,
+ "exportedOrder": 2
+ },
+ "action": "Rebuild the endnote list from first marker appearance before journal export."
+ }
+ ]
+}
diff --git a/collaborative-footnote-export-guard/reports/footnote-export-report.md b/collaborative-footnote-export-guard/reports/footnote-export-report.md
new file mode 100644
index 00000000..653deb8f
--- /dev/null
+++ b/collaborative-footnote-export-guard/reports/footnote-export-report.md
@@ -0,0 +1,15 @@
+# Footnote Export Guard Report
+
+Workspace: editor-room-ms-042
+Decision: block-export
+
+| Severity | Finding | Action |
+| --- | --- | --- |
+| block | Marker fn-5 is present in the manuscript without matching note text. | Add the missing note text or remove the marker before export. |
+| block | Private note fn-2 would be included in the export packet. | Redact the note or convert it to an export-safe public note after review. |
+| block | Note fn-2 changed after section methods entered final-review lock. | Ask the section owner to unlock, approve, or roll back the note edit. |
+| hold | Source-backed note fn-3 is missing a citation binding. | Bind the note to an approved bibliography entry before export. |
+| warn | Note fn-4 has text but no visible manuscript marker. | Either insert the marker in the manuscript or exclude the unused note from export. |
+| hold | Footnote marker fn-2 appears in multiple manuscript sections. | Assign unique note markers or confirm that repeated references use an explicit shared-note alias. |
+| hold | Endnote fn-2 is exported as 3, but first appears at position 2. | Rebuild the endnote list from first marker appearance before journal export. |
+| hold | Endnote fn-3 is exported as 2, but first appears at position 3. | Rebuild the endnote list from first marker appearance before journal export. |
diff --git a/collaborative-footnote-export-guard/reports/summary.svg b/collaborative-footnote-export-guard/reports/summary.svg
new file mode 100644
index 00000000..4a2f3ba7
--- /dev/null
+++ b/collaborative-footnote-export-guard/reports/summary.svg
@@ -0,0 +1,8 @@
+
\ No newline at end of file
diff --git a/collaborative-footnote-export-guard/sampleWorkspace.js b/collaborative-footnote-export-guard/sampleWorkspace.js
new file mode 100644
index 00000000..d747d781
--- /dev/null
+++ b/collaborative-footnote-export-guard/sampleWorkspace.js
@@ -0,0 +1,66 @@
+module.exports = {
+ id: "editor-room-ms-042",
+ checkedAt: "2026-05-30T19:30:00.000Z",
+ sections: [
+ {
+ id: "methods",
+ locked: true,
+ lockReason: "final-review",
+ markers: ["fn-1", "fn-2"]
+ },
+ {
+ id: "results",
+ locked: false,
+ markers: ["fn-2", "fn-3", "fn-5"]
+ },
+ {
+ id: "discussion",
+ locked: false,
+ markers: []
+ }
+ ],
+ notes: [
+ {
+ id: "fn-1",
+ sectionId: "methods",
+ text: "Protocol preregistration details.",
+ visibility: "public",
+ owner: "author-a",
+ requiresCitation: true,
+ citationKey: "doe2026protocol",
+ exportedOrder: 1,
+ modifiedAfterLock: false
+ },
+ {
+ id: "fn-2",
+ sectionId: "methods",
+ text: "Reviewer-only note about the assay batch.",
+ visibility: "private",
+ owner: "reviewer-7",
+ requiresCitation: false,
+ exportedOrder: 3,
+ modifiedAfterLock: true
+ },
+ {
+ id: "fn-3",
+ sectionId: "results",
+ text: "Derived from the instrument calibration record.",
+ visibility: "public",
+ owner: "author-b",
+ requiresCitation: true,
+ citationKey: "",
+ exportedOrder: 2,
+ modifiedAfterLock: false
+ },
+ {
+ id: "fn-4",
+ sectionId: "discussion",
+ text: "Unused historical note from an earlier draft.",
+ visibility: "public",
+ owner: "author-c",
+ requiresCitation: false,
+ exportedOrder: 4,
+ modifiedAfterLock: false
+ }
+ ]
+};
diff --git a/collaborative-footnote-export-guard/test.js b/collaborative-footnote-export-guard/test.js
new file mode 100644
index 00000000..a5117515
--- /dev/null
+++ b/collaborative-footnote-export-guard/test.js
@@ -0,0 +1,52 @@
+const assert = require("assert");
+const { evaluateFootnoteExport } = require("./footnoteExportGuard");
+const sampleWorkspace = require("./sampleWorkspace");
+
+const result = evaluateFootnoteExport(sampleWorkspace);
+
+assert.equal(result.decision, "block-export");
+assert.equal(result.summary.sections, 3);
+assert.equal(result.summary.notes, 4);
+assert.equal(result.summary.markers, 4);
+assert.ok(result.findings.some((finding) => finding.id === "orphan-marker:fn-5"));
+assert.ok(result.findings.some((finding) => finding.id === "private-note:fn-2"));
+assert.ok(result.findings.some((finding) => finding.id === "locked-section-note-edit:fn-2"));
+assert.ok(result.findings.some((finding) => finding.id === "missing-citation:fn-3"));
+assert.ok(result.findings.some((finding) => finding.id === "unused-note:fn-4"));
+assert.ok(result.findings.some((finding) => finding.id === "duplicate-marker:fn-2"));
+assert.ok(result.findings.some((finding) => finding.id === "endnote-order:fn-2"));
+
+const cleanWorkspace = {
+ id: "editor-room-clean",
+ sections: [
+ { id: "intro", locked: false, markers: ["fn-1"] },
+ { id: "methods", locked: true, lockReason: "final-review", markers: ["fn-2"] }
+ ],
+ notes: [
+ {
+ id: "fn-1",
+ sectionId: "intro",
+ text: "Open science statement.",
+ visibility: "public",
+ requiresCitation: true,
+ citationKey: "nguyen2026open",
+ exportedOrder: 1,
+ modifiedAfterLock: false
+ },
+ {
+ id: "fn-2",
+ sectionId: "methods",
+ text: "Instrument model reference.",
+ visibility: "public",
+ requiresCitation: false,
+ exportedOrder: 2,
+ modifiedAfterLock: false
+ }
+ ]
+};
+
+const cleanResult = evaluateFootnoteExport(cleanWorkspace);
+assert.equal(cleanResult.decision, "ready-for-export");
+assert.equal(cleanResult.findings.length, 0);
+
+console.log("footnote export guard tests passed");