diff --git a/erpnext_github_integration/github_api.py b/erpnext_github_integration/github_api.py
index 07f4693..53aa41d 100644
--- a/erpnext_github_integration/github_api.py
+++ b/erpnext_github_integration/github_api.py
@@ -299,29 +299,61 @@ def add_pr_reviewer(repo_full_name, pr_number, reviewers):
     token = settings.get_password('personal_access_token')
     if not token:
         frappe.throw(_('GitHub Personal Access Token not configured in GitHub Settings'))
+
+    # normalize reviewers input
     if isinstance(reviewers, str):
         try:
             reviewers = json.loads(reviewers)
         except Exception:
             reviewers = [r.strip() for r in reviewers.split(',') if r.strip()]
-    payload = {'reviewers': reviewers}
+
+    github_usernames = []
+
     try:
-        resp = github_request('POST', f"/repos/{repo_full_name}/pulls/{pr_number}/requested_reviewers", token, data=payload)
+        local = frappe.get_doc('Repository Pull Request', {
+            'repository': repo_full_name,
+            'pr_number': int(pr_number)
+        })
+
+        # Reset reviewers table
+        local.set('reviewers_table', [])
+
+        for user_id in reviewers:
+            # map ERPNext user → GitHub username
+            gh_username = frappe.db.get_value("User", user_id, "github_username")
+
+            if not gh_username:
+                frappe.log_error(
+                    f"User {user_id} has no GitHub username set",
+                    "GitHub Reviewer Mapping"
+                )
+                continue  # skip if no GitHub username
+
+            github_usernames.append(gh_username)
+
+            # store ERPNext user (email / id) in local doc
+            local.append('reviewers_table', {
+                'pull_request': local.name,
+                'user': user_id
+            })
+
+        local.save(ignore_permissions=True)
+
+    except Exception:
+        frappe.log_error(frappe.get_traceback(), "Failed to update local Repository Pull Request reviewers")
+
+    # send to GitHub (GitHub API needs GitHub usernames)
+    payload = {'reviewers': github_usernames}
+    try:
+        resp = github_request(
+            'POST',
+            f"/repos/{repo_full_name}/pulls/{pr_number}/requested_reviewers",
+            token,
+            data=payload
+        )
     except Exception as e:
         frappe.throw(_('GitHub add PR reviewer failed: {0}').format(str(e)))
-    if resp:
-        try:
-            local = frappe.get_doc('Repository Pull Request', {'repository': repo_full_name, 'pr_number': int(pr_number)})
-            # Update reviewers table
-            local.set('reviewers_table', [])
-            for reviewer in reviewers:
-                local.append('reviewers_table', {
-                    'user': reviewer
-                })
-            local.save(ignore_permissions=True)
-        except Exception:
-            pass
-        return resp
+
     return resp
 
 @frappe.whitelist()
diff --git a/erpnext_github_integration/public/js/task_client.js b/erpnext_github_integration/public/js/task_client.js
index 0741c33..76eccc8 100644
--- a/erpnext_github_integration/public/js/task_client.js
+++ b/erpnext_github_integration/public/js/task_client.js
@@ -24,8 +24,6 @@ frappe.ui.form.on('Task', {
                             // Save both: local doc link & GitHub issue number
                             frm.set_value('github_issue_doc', r.message.local_doc);
                             frm.set_value('github_issue_number', issue.number);
-                            frm.set_value('github_repo', repo);
-
                             frm.save();
                         }
                     }
@@ -47,12 +45,13 @@ frappe.ui.form.on('Task', {
             ], function(values){
                 frappe.call({
                     method: 'erpnext_github_integration.github_api.create_pull_request',
-                    args: {repo_full_name: repo, title: values.title, head: values.head, base: values.base, body: values.body},
+                    args: {repository: repo, title: values.title, head: values.head, base: values.base, body: values.body},
                     callback: function(r) {
                         if (r.message) {
-                            frappe.msgprint(__('Created PR: {0}').format(r.message.pull_request.get('html_url') || ''));
-                            frm.set_value('github_pr_number', r.message.pull_request.get('number'));
-                            frm.set_value('github_repo', repo);
+                            let pr = r.message.pull_request;
+                            let url = pr.html_url || pr.url;
+                            frappe.msgprint(__('Created pull request: <a href="{0}" target="_blank">{0}</a>').format(url));
+                            frm.set_value('github_pr_number', pr.number);
                             frm.save();
                         }
                     }
@@ -104,25 +103,54 @@ frappe.ui.form.on('Task', {
             });
         });
 
-        frm.add_custom_button(__('Add PR Reviewer'), function() {
+        frm.add_custom_button(__('Assign PR Reviewer'), function() {
             let repo = frm.doc.github_repo;
-            let pr_no = frm.doc.github_pr_number;
-            if (!repo || !pr_no) {
+            let pr_number = frm.doc.github_pr_number;
+
+            if (!repo || !pr_number) {
                 frappe.msgprint(__('This Task must have GitHub Repo and GitHub PR Number set.'));
                 return;
             }
-            frappe.prompt([
-                {'fieldname':'reviewers','fieldtype':'Data','label':'Reviewers (comma separated GitHub usernames)','reqd':1}
-            ], function(values){
-                frappe.call({
-                    method: 'erpnext_github_integration.github_api.add_pr_reviewer',
-                    args: {repo_full_name: repo, pr_number: pr_no, reviewers: values.reviewers},
-                    callback: function(r) {
-                        frappe.msgprint(__('Added reviewers to PR {0}').format(pr_no));
+
+            // fetch ERPNext users with github_username set
+            frappe.db.get_list('User', {
+                fields: ['name', 'full_name', 'github_username'],
+                filters: { enabled: 1, github_username: ['!=', ''] },
+                limit: 100
+            }).then(users => {
+                let user_options = users.map(u => ({
+                    value: u.name,
+                    label: `${u.full_name || u.name} (${u.github_username || 'no GitHub'})`
+                }));
+
+                frappe.prompt([
+                    {
+                        fieldname: 'reviewers',
+                        fieldtype: 'MultiSelectPills',
+                        label: 'Reviewers',
+                        options: user_options,
+                        reqd: 1
                     }
-                });
-            }, __('Add PR Reviewer'));
-        });
+                ], function(values) {
+                    // values.reviewers will already be an array of github_usernames
+                    let selected = values.reviewers || [];
 
+                    frappe.call({
+                        method: 'erpnext_github_integration.github_api.add_pr_reviewer',
+                        args: {
+                            repo_full_name: repo,
+                            pr_number: pr_number,
+                            reviewers: selected
+                        },
+                        callback: function(r) {
+                            if (r.message) {
+                                frappe.msgprint("Message: " + r.message);
+                                frappe.msgprint(__('Reviewers assigned to PR {0}', [pr_number]));
+                            }
+                        }
+                    });
+                }, __('Assign PR Reviewer'));
+            });
+        });
     }
 });