diff --git a/src/lib/server/stock-pricing-service.test.ts b/src/lib/server/stock-pricing-service.test.ts
index 4997001..b49dfae 100644
--- a/src/lib/server/stock-pricing-service.test.ts
+++ b/src/lib/server/stock-pricing-service.test.ts
@@ -143,4 +143,46 @@ describe("updateStockItemsPricing — stock_ledger audit on cost change", () =>
 
     expect(ledgerCreates).toEqual([]);
   });
+
+  it("does NOT write a stock_ledger row when prior cost_price is undefined (first-time pricing)", async () => {
+    const before = {
+      id: "abcdefghijklmno",
+      // cost_price intentionally missing — fresh catalogue row.
+      selling_price: 0,
+      markup: 0,
+    };
+    const updated = { ...before, cost_price: 2.5 };
+    const { pb, ledgerCreates } = stubPb(before, updated);
+
+    await updateStockItemsPricing({
+      pb: pb as never,
+      updates: [{ id: "abcdefghijklmno", costPrice: 2.5 }],
+      actor: { id: "useropid1234567", name: "Gary" },
+    } as UpdateStockItemsPricingInput);
+
+    expect(ledgerCreates).toEqual([]);
+  });
+
+  it("records an old → new delta in the notes string when costPrice changes", async () => {
+    const before = {
+      id: "abcdefghijklmno",
+      cost_price: 2.5,
+      selling_price: 3.25,
+      markup: 30,
+    };
+    const updated = { ...before, cost_price: 3.2 };
+    const { pb, ledgerCreates } = stubPb(before, updated);
+
+    await updateStockItemsPricing({
+      pb: pb as never,
+      updates: [{ id: "abcdefghijklmno", costPrice: 3.2 }],
+      actor: { id: "useropid1234567", name: "Gary" },
+    } as UpdateStockItemsPricingInput);
+
+    expect(ledgerCreates).toEqual([
+      expect.objectContaining({
+        notes: "Gary edited cost 2.5 → 3.2 from /stock",
+      }),
+    ]);
+  });
 });
diff --git a/src/lib/server/stock-pricing-service.ts b/src/lib/server/stock-pricing-service.ts
index c3ffe2b..8707a4b 100644
--- a/src/lib/server/stock-pricing-service.ts
+++ b/src/lib/server/stock-pricing-service.ts
@@ -152,11 +152,14 @@ export async function updateStockItemsPricing(
     }
 
     // 3.5. Cost audit — write a stock_ledger row ONLY when costPrice was
-    //      supplied and differs from the existing cost_price. Side-effect:
-    //      a failed ledger write aborts THIS row (we won't half-write the
-    //      patch without recording the audit trail).
+    //      supplied AND the prior cost was a real number AND it differs.
+    //      First-time pricing (before.cost_price undefined) is NOT a
+    //      cost movement to audit — it's a field initialisation.
+    //      Side-effect: a failed ledger write aborts THIS row (we won't
+    //      half-write the patch without recording the audit trail).
     if (
       update.costPrice !== undefined &&
+      Number.isFinite(before.cost_price) &&
       before.cost_price !== update.costPrice
     ) {
       try {
@@ -166,7 +169,7 @@ export async function updateStockItemsPricing(
           unit_cost: update.costPrice,
           reason: "adjustment",
           reference_type: "manual",
-          notes: `${input.actor.name} edited cost from /stock`,
+          notes: `${input.actor.name} edited cost ${before.cost_price} → ${update.costPrice} from /stock`,
           created_by: input.actor.id,
         });
       } catch (err) {