diff --git a/fusion_plating/fusion_plating_bridge_mrp/models/mrp_production.py b/fusion_plating/fusion_plating_bridge_mrp/models/mrp_production.py
index faa19224..70d46016 100644
--- a/fusion_plating/fusion_plating_bridge_mrp/models/mrp_production.py
+++ b/fusion_plating/fusion_plating_bridge_mrp/models/mrp_production.py
@@ -1149,6 +1149,78 @@ class MrpProduction(models.Model):
             'target': 'current',
         }
 
+    # ------------------------------------------------------------------
+    # Sub 2 — Certificate requirement resolution (single source)
+    # ------------------------------------------------------------------
+    def _fp_resolve_cert_requirement(self):
+        """Resolve which certs are required for this MO.
+
+        Returns (want_coc: bool, want_thickness: bool).
+
+        Logic:
+          1. Collect every linked fp.part.catalog via the SO line walk.
+          2. For each part:
+             - if certificate_requirement != 'inherit' -> part wins
+             - else -> fall back to partner's x_fc_send_coc /
+               x_fc_send_thickness_report flags
+          3. Multi-line MO: strictest wins (any() across lines).
+          4. MO with no SO link: partner fallback; safe default (True, False).
+
+        This is the single entry point used by:
+          - _fp_generate_cert_pdf (MO-done cert cascade)
+          - QC gate when it audits thickness requirements
+          - Any future caller (Sub 6 will update this method when
+            partner-level flags move to per-location / per-contact).
+        """
+        self.ensure_one()
+        SO = self.env['sale.order']
+
+        # Resolve partner via origin
+        partner = False
+        lines = self.env['sale.order.line']
+        if self.origin:
+            so = SO.search([('name', '=', self.origin)], limit=1)
+            if so:
+                partner = so.partner_id
+                lines = so.order_line
+
+        # No SO link — use partner-level fallback with safe defaults
+        if not lines:
+            if partner and 'x_fc_send_coc' in partner._fields:
+                return (
+                    bool(partner.x_fc_send_coc),
+                    bool(partner.x_fc_send_thickness_report),
+                )
+            # No partner at all — safe default: CoC yes, thickness no
+            return (True, False)
+
+        want_coc_any = False
+        want_thickness_any = False
+        for line in lines:
+            part = line.x_fc_part_catalog_id
+            if part and part.certificate_requirement != 'inherit':
+                # Part-level override wins
+                want_coc_line = part.certificate_requirement in (
+                    'coc', 'coc_thickness',
+                )
+                want_thickness_line = (
+                    part.certificate_requirement == 'coc_thickness'
+                )
+            else:
+                # Inherit (or no part) -> partner fallback
+                if partner and 'x_fc_send_coc' in partner._fields:
+                    want_coc_line = bool(partner.x_fc_send_coc)
+                    want_thickness_line = bool(
+                        partner.x_fc_send_thickness_report
+                    )
+                else:
+                    want_coc_line = True
+                    want_thickness_line = False
+            want_coc_any = want_coc_any or want_coc_line
+            want_thickness_any = want_thickness_any or want_thickness_line
+
+        return (want_coc_any, want_thickness_any)
+
     # ------------------------------------------------------------------
     # #5 — Delivery auto-prefill helpers
     # ------------------------------------------------------------------