diff --git a/harness/.pi/extensions/gate/__tests__/builders.test.js b/harness/.pi/extensions/gate/__tests__/builders.test.js
index 11c81db0..9d7ec885 100644
--- a/harness/.pi/extensions/gate/__tests__/builders.test.js
+++ b/harness/.pi/extensions/gate/__tests__/builders.test.js
@@ -15,6 +15,7 @@ const {
   buildArtifactGate,
   buildInfoRequest,
   buildFreetextRequest,
+  buildSchemaLinkingRequest,
   withChildLinkage,
 } = require("../builders.js");
 
@@ -118,6 +119,17 @@ test("freetext request carries a title and no options", () => {
   assert.deepEqual(result.reserved, ["back", "exit", "other"]);
 });
 
+test("buildSchemaLinkingRequest carries tables + reserved", () => {
+  const out = buildSchemaLinkingRequest({
+    id: "u7", phase: "F4", title: "F4 — Schema linking",
+    tables: [{ id: "t1", name: "dim_patient", kind: "promote", columns: [] }],
+  });
+  assert.equal(out.widget, "schema-linking");
+  assert.equal(out.id, "u7");
+  assert.equal(out.tables.length, 1);
+  assert.deepEqual(out.reserved, ["back", "exit", "other"]);
+});
+
 test("withChildLinkage sets option.opens and returns the option", () => {
   const child = { widget: "freetext", title: "Motivazione del rifiuto" };
   const option = withChildLinkage({ id: "reject", label: "Rifiuta" }, child);
diff --git a/harness/.pi/extensions/gate/builders.js b/harness/.pi/extensions/gate/builders.js
index 3d70e6c6..b723332d 100644
--- a/harness/.pi/extensions/gate/builders.js
+++ b/harness/.pi/extensions/gate/builders.js
@@ -156,6 +156,24 @@ function buildFreetextRequest({ id, phase, title }) {
   };
 }
 
+// Build a `schema-linking` ui_request: table rows (promote/exclude) each carrying
+// their full catalog columns; the frontend renders rows + a per-table columns
+// modal (suggested pre-selected). `tables` is validated shallowly here.
+function buildSchemaLinkingRequest({ id, phase, title, tables }) {
+  requireString(title, "title", "schema-linking");
+  const tabs = requireArray(tables, "tables", "schema-linking");
+  return {
+    type: "ui_request",
+    id,
+    phase,
+    schema_version: SCHEMA_VERSION,
+    widget: "schema-linking",
+    title,
+    tables: [...tabs],
+    reserved: RESERVED,
+  };
+}
+
 // Attach a child-widget spec to an option (linkage, §4.2). Returns the option.
 function withChildLinkage(option, widgetSpec) {
   option.opens = widgetSpec;
@@ -168,6 +186,7 @@ module.exports = {
   buildArtifactGate,
   buildInfoRequest,
   buildFreetextRequest,
+  buildSchemaLinkingRequest,
   withChildLinkage,
   SCHEMA_VERSION,
   RESERVED,