diff --git a/.gitignore b/.gitignore
index 4c57c78..fa6fb59 100644
--- a/.gitignore
+++ b/.gitignore
@@ -127,4 +127,5 @@ _modules/*
 /public/.htaccess
 
 .serena/
-.claude/
\ No newline at end of file
+.claude/
+AGENTS.md
\ No newline at end of file
diff --git a/app/Models/Patient/PatientModel.php b/app/Models/Patient/PatientModel.php
index bd64106..5d26bdc 100644
--- a/app/Models/Patient/PatientModel.php
+++ b/app/Models/Patient/PatientModel.php
@@ -118,7 +118,17 @@ class PatientModel extends BaseModel {
     $modelPatAtt = new PatAttModel();
     $modelPatCom = new PatComModel();
     $modelPatIdt = new PatIdtModel();
-  
+
+    if (!empty($input['Custodian'])) {
+        if (is_array($input['Custodian']) && isset($input['Custodian']['InternalPID'])) {
+            $input['Custodian'] = (int) $input['Custodian']['InternalPID'];
+        }
+    }
+
+    if (!empty($input['LinkTo']) && is_array($input['LinkTo'])) {
+        $internalPids = array_column($input['LinkTo'], 'InternalPID');
+        $input['LinkTo'] = implode(',', $internalPids);
+    }
     $input['LinkTo'] = empty($input['LinkTo']) ? null : $input['LinkTo'];
 
     $db->transBegin();
@@ -160,6 +170,16 @@ class PatientModel extends BaseModel {
     $modelPatCom = new PatComModel();
     $modelPatAtt = new PatAttModel();
 
+    if (!empty($input['Custodian'])) {
+        if (is_array($input['Custodian']) && isset($input['Custodian']['InternalPID'])) {
+            $input['Custodian'] = (int) $input['Custodian']['InternalPID'];
+        }
+    }
+
+    if (!empty($input['LinkTo']) && is_array($input['LinkTo'])) {
+        $internalPids = array_column($input['LinkTo'], 'InternalPID');
+        $input['LinkTo'] = implode(',', $internalPids);
+    }
     $input['LinkTo'] = empty($input['LinkTo']) ? null : $input['LinkTo'];
 
     $db->transBegin();
diff --git a/public/api-docs.yaml b/public/api-docs.yaml
index ecc29d7..320a8f1 100644
--- a/public/api-docs.yaml
+++ b/public/api-docs.yaml
@@ -143,6 +143,36 @@ components:
           type: string
           maxLength: 255
 
+    LinkedPatient:
+      type: object
+      description: Linked patient reference
+      properties:
+        InternalPID:
+          type: integer
+          description: Internal patient ID of the linked patient
+        PatientID:
+          type: string
+          description: Patient ID of the linked patient
+
+    Custodian:
+      type: object
+      description: Patient custodian/guardian
+      properties:
+        InternalPID:
+          type: integer
+          description: Internal patient ID of the custodian
+        PatientID:
+          type: string
+          description: Patient ID of the custodian
+
+    PatAttEntry:
+      type: object
+      description: Patient address/attorney entry
+      properties:
+        Address:
+          type: string
+          description: Address text
+
     Patient:
       type: object
       required:
@@ -227,6 +257,51 @@ components:
           maxLength: 100
         PatIdt:
           $ref: '#/components/schemas/PatientIdentifier'
+        LinkTo:
+          type: array
+          description: Array of linked patient references
+          items:
+            $ref: '#/components/schemas/LinkedPatient'
+        Custodian:
+          $ref: '#/components/schemas/Custodian'
+        DeathIndicator:
+          type: string
+          enum: [Y, N]
+          description: 'Y: Yes (deceased), N: No (alive)'
+        TimeOfDeath:
+          type: string
+          format: date-time
+          description: ISO 8601 UTC datetime of death
+        PatCom:
+          type: string
+          description: Patient comment/notes
+        PatAtt:
+          type: array
+          description: Patient address entries
+          items:
+            $ref: '#/components/schemas/PatAttEntry'
+        Province:
+          type: string
+          description: Province area code
+        City:
+          type: string
+          description: City area code
+        Country:
+          type: string
+          maxLength: 100
+        Race:
+          type: string
+          maxLength: 100
+        MaritalStatus:
+          type: string
+          enum: [A, B, D, M, S, W]
+          description: 'A: Annulled, B: Separated, D: Divorced, M: Married, S: Single, W: Widowed'
+        Religion:
+          type: string
+          maxLength: 100
+        Ethnic:
+          type: string
+          maxLength: 100
 
     PatientListResponse:
       type: object