diff --git a/artifacts/api-server/src/routes/protocol.ts b/artifacts/api-server/src/routes/protocol.ts
index caec4d1c..88b87db2 100644
--- a/artifacts/api-server/src/routes/protocol.ts
+++ b/artifacts/api-server/src/routes/protocol.ts
@@ -939,9 +939,39 @@ router.post(
       res.status(201).json(row);
     } catch (e) {
       // Unique start_time violation → a slot already starts at this time.
+      // Duplicate rule is per-day: if the requested days don't overlap the
+      // existing slot's days, merge them instead of rejecting.
       if (isUniqueViolation(e)) {
+        const requestedDays = body.daysOfWeek ?? [0, 1, 2, 3, 4, 5, 6];
+        const [existing] = await db
+          .select()
+          .from(protocolBookingSlotsTable)
+          .where(eq(protocolBookingSlotsTable.startTime, body.startTime));
+        if (
+          existing &&
+          !existing.daysOfWeek.some((d) => requestedDays.includes(d))
+        ) {
+          const union = Array.from(
+            new Set([...existing.daysOfWeek, ...requestedDays]),
+          ).sort((a, b) => a - b);
+          const [row] = await db
+            .update(protocolBookingSlotsTable)
+            .set({ daysOfWeek: union })
+            .where(eq(protocolBookingSlotsTable.id, existing.id))
+            .returning();
+          await logAudit(db, {
+            action: "slot.update",
+            entityType: "booking_slot",
+            entityId: existing.id,
+            oldValue: existing,
+            newValue: row,
+            performedBy: req.session.userId!,
+          });
+          res.status(201).json(row);
+          return;
+        }
         res.status(409).json({
-          error: "يوجد وقت حجز يبدأ في نفس التوقيت.",
+          error: "يوجد وقت حجز يبدأ في نفس التوقيت في نفس اليوم.",
           code: "duplicate_slot",
         });
         return;
@@ -953,8 +983,9 @@ router.post(
 
 // Generate slots from a weekly availability interval (Calendly-style):
 // every `durationMinutes` step in [startTime, endTime) whose full duration
-// still fits becomes a slot on the given days. Start times that already
-// exist are skipped (global start_time uniqueness), never overwritten.
+// still fits becomes a slot on the given days. Duplicate rule is per-day:
+// if a slot already starts at the same time, the requested days are merged
+// into it (its duration is kept); only fully-covered times are skipped.
 router.post(
   "/protocol/booking-slots/generate",
   requireManageRooms,
@@ -974,32 +1005,74 @@ router.post(
       });
       return;
     }
-    const inserted = await db
-      .insert(protocolBookingSlotsTable)
-      .values(
-        candidates.map((startTime) => ({
-          startTime,
-          durationMinutes: body.durationMinutes,
-          daysOfWeek: body.daysOfWeek,
-          createdBy: req.session.userId!,
-        })),
-      )
-      .onConflictDoNothing({ target: protocolBookingSlotsTable.startTime })
-      .returning();
-    for (const row of inserted) {
-      await logAudit(db, {
-        action: "slot.create",
-        entityType: "booking_slot",
-        entityId: row.id,
-        newValue: row,
-        performedBy: req.session.userId!,
-      });
-    }
-    res.status(201).json({
-      created: inserted.length,
-      skipped: candidates.length - inserted.length,
-      slots: inserted,
+    const result = await db.transaction(async (tx) => {
+      const existingRows = await tx
+        .select()
+        .from(protocolBookingSlotsTable)
+        .where(inArray(protocolBookingSlotsTable.startTime, candidates))
+        .for("update");
+      const byStart = new Map(existingRows.map((r) => [r.startTime, r]));
+      const slots: (typeof existingRows)[number][] = [];
+      let created = 0;
+      let merged = 0;
+      let skipped = 0;
+      for (const startTime of candidates) {
+        const existing = byStart.get(startTime);
+        if (!existing) {
+          const [row] = await tx
+            .insert(protocolBookingSlotsTable)
+            .values({
+              startTime,
+              durationMinutes: body.durationMinutes,
+              daysOfWeek: body.daysOfWeek,
+              createdBy: req.session.userId!,
+            })
+            .onConflictDoNothing({
+              target: protocolBookingSlotsTable.startTime,
+            })
+            .returning();
+          if (!row) {
+            skipped += 1;
+            continue;
+          }
+          created += 1;
+          slots.push(row);
+          await logAudit(tx, {
+            action: "slot.create",
+            entityType: "booking_slot",
+            entityId: row.id,
+            newValue: row,
+            performedBy: req.session.userId!,
+          });
+          continue;
+        }
+        const union = Array.from(
+          new Set([...existing.daysOfWeek, ...body.daysOfWeek]),
+        ).sort((a, b) => a - b);
+        if (union.length === existing.daysOfWeek.length) {
+          // All requested days already covered at this start time.
+          skipped += 1;
+          continue;
+        }
+        const [row] = await tx
+          .update(protocolBookingSlotsTable)
+          .set({ daysOfWeek: union })
+          .where(eq(protocolBookingSlotsTable.id, existing.id))
+          .returning();
+        merged += 1;
+        slots.push(row);
+        await logAudit(tx, {
+          action: "slot.update",
+          entityType: "booking_slot",
+          entityId: existing.id,
+          oldValue: existing,
+          newValue: row,
+          performedBy: req.session.userId!,
+        });
+      }
+      return { created, merged, skipped, slots };
     });
+    res.status(201).json(result);
   },
 );
 
diff --git a/artifacts/api-server/tests/protocol-booking-slots.test.mjs b/artifacts/api-server/tests/protocol-booking-slots.test.mjs
index 173b2f3f..7c760611 100644
--- a/artifacts/api-server/tests/protocol-booking-slots.test.mjs
+++ b/artifacts/api-server/tests/protocol-booking-slots.test.mjs
@@ -513,8 +513,31 @@ test("interval generation creates slots, skips duplicates, validates input", asy
   assert.equal(again.status, 201);
   const b2 = await again.json();
   assert.equal(b2.created, 0);
+  assert.equal(b2.merged, 0);
   assert.equal(b2.skipped, 3);
 
+  // Same start times but a *different* day: not a duplicate — the day is
+  // merged into the existing slots instead of being skipped.
+  const otherDayGen = await api(
+    adminCookie,
+    "POST",
+    "/protocol/booking-slots/generate",
+    {
+      startTime: "18:07",
+      endTime: "19:37",
+      durationMinutes: 30,
+      daysOfWeek: [otherWeekday],
+    },
+  );
+  assert.equal(otherDayGen.status, 201);
+  const b2b = await otherDayGen.json();
+  assert.equal(b2b.created, 0);
+  assert.equal(b2b.merged, 3, "different day must merge, not skip");
+  assert.equal(b2b.skipped, 0);
+  for (const s of b2b.slots) {
+    assert.deepEqual(s.daysOfWeek, [dayWeekday, otherWeekday].sort((a, b) => a - b));
+  }
+
   // Overlapping an existing start time (SLOT_A) only creates the free ones.
   const overlap = await api(adminCookie, "POST", "/protocol/booking-slots/generate", {
     startTime: SLOT_A,
@@ -524,7 +547,8 @@ test("interval generation creates slots, skips duplicates, validates input", asy
   });
   assert.equal(overlap.status, 201);
   const b3 = await overlap.json();
-  assert.equal(b3.skipped, 1, "existing SLOT_A start must be skipped");
+  assert.equal(b3.skipped, 1, "SLOT_A already covers all days → skipped");
+  assert.equal(b3.merged, 0);
   assert.equal(b3.created, 1);
 
   // Invalid inputs are rejected.
@@ -599,4 +623,26 @@ test("availability and booking validation filter slots by weekday", async () =>
   });
   assert.equal(wrongDay.status, 400);
   assert.equal((await wrongDay.json()).code, "invalid_slot");
+
+  // Manual create at the same start time: overlapping day → 409; a
+  // disjoint day is merged into the existing slot instead.
+  const dup = await api(adminCookie, "POST", "/protocol/booking-slots", {
+    startTime: "21:11",
+    durationMinutes: DURATION,
+    daysOfWeek: [otherWeekday],
+  });
+  assert.equal(dup.status, 409, "same time + same day is a duplicate");
+  const mergeDay = (otherWeekday + 1) % 7;
+  const mergedRes = await api(adminCookie, "POST", "/protocol/booking-slots", {
+    startTime: "21:11",
+    durationMinutes: DURATION,
+    daysOfWeek: [mergeDay],
+  });
+  assert.equal(mergedRes.status, 201, "same time + new day merges");
+  const mergedRow = await mergedRes.json();
+  assert.equal(mergedRow.id, offDay.id, "must merge into the existing slot");
+  assert.deepEqual(
+    mergedRow.daysOfWeek,
+    [otherWeekday, mergeDay].sort((a, b) => a - b),
+  );
 });
diff --git a/artifacts/tx-os/src/locales/ar.json b/artifacts/tx-os/src/locales/ar.json
index 6f854c14..3217e5ba 100644
--- a/artifacts/tx-os/src/locales/ar.json
+++ b/artifacts/tx-os/src/locales/ar.json
@@ -1930,10 +1930,10 @@
       "intervalFrom": "من",
       "intervalTo": "إلى",
       "generate": "توليد الأوقات",
-      "generated": "تم توليد {{created}} وقتًا (تم تجاهل {{skipped}} مكررًا)",
-      "generatedNone": "لم يتولد أي وقت — كل الأوقات موجودة مسبقًا.",
+      "generated": "تم توليد {{created}} وقتًا، ودمج الأيام في {{merged}}، وتجاهل {{skipped}} مكررًا.",
+      "generatedNone": "لا جديد — كل الأوقات والأيام موجودة مسبقًا.",
       "pickDay": "اختر يومًا واحدًا على الأقل",
       "noSlotsForDay": "لا توجد أوقات متاحة في هذا اليوم"
     }
   }
-}
+}
\ No newline at end of file
diff --git a/artifacts/tx-os/src/locales/en.json b/artifacts/tx-os/src/locales/en.json
index 6d0d9a92..4dd0f9ba 100644
--- a/artifacts/tx-os/src/locales/en.json
+++ b/artifacts/tx-os/src/locales/en.json
@@ -1783,10 +1783,10 @@
       "intervalFrom": "From",
       "intervalTo": "To",
       "generate": "Generate slots",
-      "generated": "{{created}} slot(s) generated ({{skipped}} duplicate(s) skipped)",
-      "generatedNone": "No slots generated — all start times already exist.",
+      "generated": "{{created}} slot(s) created, days merged into {{merged}}, {{skipped}} duplicate(s) skipped.",
+      "generatedNone": "Nothing new — all start times and days already exist.",
       "pickDay": "Pick at least one day",
       "noSlotsForDay": "No slots available on this day"
     }
   }
-}
+}
\ No newline at end of file
diff --git a/artifacts/tx-os/src/pages/protocol.tsx b/artifacts/tx-os/src/pages/protocol.tsx
index 08be71a9..fcc1cbdf 100644
--- a/artifacts/tx-os/src/pages/protocol.tsx
+++ b/artifacts/tx-os/src/pages/protocol.tsx
@@ -2488,7 +2488,7 @@ function SlotsAdminSection({
   });
   const generateMut = useMutation({
     mutationFn: () =>
-      apiJson<{ created: number; skipped: number }>(
+      apiJson<{ created: number; merged: number; skipped: number }>(
         `${API}/protocol/booking-slots/generate`,
         {
           method: "POST",
@@ -2503,10 +2503,11 @@ function SlotsAdminSection({
     onSuccess: (r) => {
       toast({
         title:
-          r.created === 0
+          r.created === 0 && r.merged === 0
             ? t("protocol.slots.generatedNone")
             : t("protocol.slots.generated", {
                 created: r.created,
+                merged: r.merged,
                 skipped: r.skipped,
               }),
       });