diff --git a/ai/provider/openai/classes/aimodel/gpt4o.php b/ai/provider/openai/classes/aimodel/gpt4o.php
index 07e89eef1ad..67df0b81ed6 100644
--- a/ai/provider/openai/classes/aimodel/gpt4o.php
+++ b/ai/provider/openai/classes/aimodel/gpt4o.php
@@ -55,11 +55,11 @@ class gpt4o extends base implements openai_base {
 
         $mform->addElement(
             'text',
-            'max_tokens',
-            get_string('settings_max_tokens', 'aiprovider_openai'),
+            'max_completion_tokens',
+            get_string('settings_max_completion_tokens', 'aiprovider_openai'),
         );
-        $mform->setType('max_tokens', PARAM_INT);
-        $mform->addHelpButton('max_tokens', 'settings_max_tokens', 'aiprovider_openai');
+        $mform->setType('max_completion_tokens', PARAM_INT);
+        $mform->addHelpButton('max_completion_tokens', 'settings_max_completion_tokens', 'aiprovider_openai');
 
         $mform->addElement(
             'text',
diff --git a/ai/provider/openai/classes/aimodel/o1.php b/ai/provider/openai/classes/aimodel/o1.php
index 3a5c2bdc6d6..43e632752dd 100644
--- a/ai/provider/openai/classes/aimodel/o1.php
+++ b/ai/provider/openai/classes/aimodel/o1.php
@@ -16,6 +16,8 @@
 
 namespace aiprovider_openai\aimodel;
 
+use MoodleQuickForm;
+
 /**
  * O1 AI model.
  *
@@ -40,6 +42,17 @@ class o1 extends gpt4o {
         return true;
     }
 
+    #[\Override]
+    public function add_model_settings(MoodleQuickForm $mform): void {
+        $mform->addElement(
+            'text',
+            'max_completion_tokens',
+            get_string('settings_max_completion_tokens', 'aiprovider_openai'),
+        );
+        $mform->setType('max_completion_tokens', PARAM_INT);
+        $mform->addHelpButton('max_completion_tokens', 'settings_max_completion_tokens', 'aiprovider_openai');
+    }
+
     #[\Override]
     public function model_type(): array {
         return [self::MODEL_TYPE_TEXT];
diff --git a/ai/provider/openai/classes/form/action_form.php b/ai/provider/openai/classes/form/action_form.php
index bbd1260c023..c2dd846d8bb 100644
--- a/ai/provider/openai/classes/form/action_form.php
+++ b/ai/provider/openai/classes/form/action_form.php
@@ -84,8 +84,23 @@ class action_form extends action_settings_form {
                 } else {
                     // Set the model to the selected model template.
                     $data->model = $data->modeltemplate;
-                }
 
+                    // Cast settings to their intended types.
+                    if ($data->model === 'gpt-4o' || $data->model === 'o1') {
+                        if (isset($data->top_p)) {
+                            $data->top_p = floatval($data->top_p);
+                        }
+                        if (isset($data->max_completion_tokens)) {
+                            $data->max_completion_tokens = intval($data->max_completion_tokens);
+                        }
+                        if (isset($data->presence_penalty)) {
+                            $data->presence_penalty = floatval($data->presence_penalty);
+                        }
+                        if (isset($data->frequency_penalty)) {
+                            $data->frequency_penalty = floatval($data->frequency_penalty);
+                        }
+                    }
+                }
             }
             // Unset the model template.
             unset($data->custommodel);
diff --git a/ai/provider/openai/lang/en/aiprovider_openai.php b/ai/provider/openai/lang/en/aiprovider_openai.php
index 421884dd703..2552fb87608 100644
--- a/ai/provider/openai/lang/en/aiprovider_openai.php
+++ b/ai/provider/openai/lang/en/aiprovider_openai.php
@@ -48,7 +48,7 @@ $string['extraparams_help'] = 'Extra parameters can be configured here. We suppo
 <pre>
 {
     "temperature": 0.5,
-    "max_tokens": 100
+    "max_completion_tokens": 100
 }
 </pre>';
 $string['invalidjson'] = 'Invalid JSON string';
@@ -65,8 +65,8 @@ $string['settings'] = 'Settings';
 $string['settings_frequency_penalty'] = 'frequency_penalty';
 $string['settings_frequency_penalty_help'] = 'The frequency penalty adjusts how often words are repeated. The higher the penalty, the less repetitions in the generated text.';
 $string['settings_help'] = 'Adjust the settings below to customise how requests are sent to OpenAI.';
-$string['settings_max_tokens'] = 'max_tokens';
-$string['settings_max_tokens_help'] = 'The maximum number of tokens used in the generated text.';
+$string['settings_max_completion_tokens'] = 'max_completion_tokens';
+$string['settings_max_completion_tokens_help'] = 'The maximum number of tokens used in the generated text.';
 $string['settings_presence_penalty'] = 'presence_penalty';
 $string['settings_presence_penalty_help'] = 'The presence penalty encourages the model to use new words by increasing the likelihood of choosing words it hasn\'t used before. A higher value makes the generated text more diverse, while a lower value allows more repetition.';
 $string['settings_top_p'] = 'top_p';
@@ -88,3 +88,5 @@ $string['globalratelimit_desc'] = 'The number of site-wide requests allowed per
 $string['orgid_desc'] = 'Get an OpenAI organization ID from your <a href="https://platform.openai.com/account/org-settings">OpenAI Platform account</a>.';
 $string['userratelimit'] = 'Maximum number of requests per user';
 $string['userratelimit_desc'] = 'The number of requests allowed per hour, per user.';
+$string['settings_max_tokens'] = 'max_tokens';
+$string['settings_max_tokens_help'] = 'The maximum number of tokens used in the generated text.';
diff --git a/ai/provider/openai/lang/en/deprecated.txt b/ai/provider/openai/lang/en/deprecated.txt
index 612439be544..1856a3afd1c 100644
--- a/ai/provider/openai/lang/en/deprecated.txt
+++ b/ai/provider/openai/lang/en/deprecated.txt
@@ -13,3 +13,5 @@ globalratelimit_desc,aiprovider_openai
 orgid_desc,aiprovider_openai
 userratelimit,aiprovider_openai
 userratelimit_desc,aiprovider_openai
+settings_max_tokens,aiprovider_openai
+settings_max_tokens_help,aiprovider_openai
diff --git a/ai/provider/openai/tests/process_generate_image_test.php b/ai/provider/openai/tests/process_generate_image_test.php
index 78620fffb3b..fb829763019 100644
--- a/ai/provider/openai/tests/process_generate_image_test.php
+++ b/ai/provider/openai/tests/process_generate_image_test.php
@@ -132,7 +132,7 @@ final class process_generate_image_test extends \advanced_testcase {
             actionconfig: [
                 'model' => 'dall-e-3',
                 'temperature' => '0.5',
-                'max_tokens' => '100',
+                'max_completion_tokens' => '100',
             ],
         );
         $processor = new process_generate_image($this->provider, $this->action);
@@ -145,13 +145,13 @@ final class process_generate_image_test extends \advanced_testcase {
 
         $this->assertEquals('dall-e-3', $body->model);
         $this->assertEquals('0.5', $body->temperature);
-        $this->assertEquals('100', $body->max_tokens);
+        $this->assertEquals('100', $body->max_completion_tokens);
 
         $this->provider = $this->create_provider(
             actionclass: \core_ai\aiactions\generate_image::class,
             actionconfig: [
                 'model' => 'my-custom-gpt',
-                'modelextraparams' => '{"temperature": 0.5,"max_tokens": 100}',
+                'modelextraparams' => '{"temperature": 0.5,"max_completion_tokens": 100}',
             ],
         );
         $processor = new process_generate_image($this->provider, $this->action);
@@ -164,7 +164,7 @@ final class process_generate_image_test extends \advanced_testcase {
 
         $this->assertEquals('my-custom-gpt', $body->model);
         $this->assertEquals('0.5', $body->temperature);
-        $this->assertEquals('100', $body->max_tokens);
+        $this->assertEquals('100', $body->max_completion_tokens);
     }
 
     /**
diff --git a/ai/provider/openai/tests/process_generate_text_test.php b/ai/provider/openai/tests/process_generate_text_test.php
index c98284b12fc..d2cbdd11cd3 100644
--- a/ai/provider/openai/tests/process_generate_text_test.php
+++ b/ai/provider/openai/tests/process_generate_text_test.php
@@ -102,7 +102,7 @@ final class process_generate_text_test extends \advanced_testcase {
             actionconfig: [
                 'systeminstruction' => get_string('action_generate_text_instruction', 'core_ai'),
                 'temperature' => '0.5',
-                'max_tokens' => '100',
+                'max_completion_tokens' => '100',
             ],
         );
         $processor = new process_generate_text($this->provider, $this->action);
@@ -115,14 +115,14 @@ final class process_generate_text_test extends \advanced_testcase {
 
         $this->assertEquals('gpt-4o', $body->model);
         $this->assertEquals('0.5', $body->temperature);
-        $this->assertEquals('100', $body->max_tokens);
+        $this->assertEquals('100', $body->max_completion_tokens);
 
         $this->provider = $this->create_provider(
             actionclass: \core_ai\aiactions\generate_text::class,
             actionconfig: [
                 'model' => 'my-custom-gpt',
                 'systeminstruction' => get_string('action_generate_text_instruction', 'core_ai'),
-                'modelextraparams' => '{"temperature": 0.5,"max_tokens": 100}',
+                'modelextraparams' => '{"temperature": 0.5,"max_completion_tokens": 100}',
             ],
         );
         $processor = new process_generate_text($this->provider, $this->action);
@@ -135,7 +135,7 @@ final class process_generate_text_test extends \advanced_testcase {
 
         $this->assertEquals('my-custom-gpt', $body->model);
         $this->assertEquals('0.5', $body->temperature);
-        $this->assertEquals('100', $body->max_tokens);
+        $this->assertEquals('100', $body->max_completion_tokens);
     }
 
     /**
diff --git a/ai/provider/openai/tests/process_summarise_text_test.php b/ai/provider/openai/tests/process_summarise_text_test.php
index 06d3004a478..84d8ea65297 100644
--- a/ai/provider/openai/tests/process_summarise_text_test.php
+++ b/ai/provider/openai/tests/process_summarise_text_test.php
@@ -104,7 +104,7 @@ final class process_summarise_text_test extends \advanced_testcase {
             actionconfig: [
                 'systeminstruction' => get_string('action_summarise_text_instruction', 'core_ai'),
                 'temperature' => '0.5',
-                'max_tokens' => '100',
+                'max_completion_tokens' => '100',
             ],
         );
         $processor = new process_summarise_text($this->provider, $this->action);
@@ -117,14 +117,14 @@ final class process_summarise_text_test extends \advanced_testcase {
 
         $this->assertEquals('gpt-4o', $body->model);
         $this->assertEquals('0.5', $body->temperature);
-        $this->assertEquals('100', $body->max_tokens);
+        $this->assertEquals('100', $body->max_completion_tokens);
 
         $this->provider = $this->create_provider(
             actionclass: \core_ai\aiactions\summarise_text::class,
             actionconfig: [
                 'model' => 'my-custom-gpt',
                 'systeminstruction' => get_string('action_summarise_text_instruction', 'core_ai'),
-                'modelextraparams' => '{"temperature": 0.5,"max_tokens": 100}',
+                'modelextraparams' => '{"temperature": 0.5,"max_completion_tokens": 100}',
             ],
         );
         $processor = new process_summarise_text($this->provider, $this->action);
@@ -137,7 +137,7 @@ final class process_summarise_text_test extends \advanced_testcase {
 
         $this->assertEquals('my-custom-gpt', $body->model);
         $this->assertEquals('0.5', $body->temperature);
-        $this->assertEquals('100', $body->max_tokens);
+        $this->assertEquals('100', $body->max_completion_tokens);
     }
 
     /**
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 310a238436a..81daa665b77 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -1797,5 +1797,62 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2025041400.09);
     }
 
+    if ($oldversion < 2025041401.08) {
+        // Get all OpenAI providers.
+        $records = $DB->get_records('ai_providers', ['provider' => 'aiprovider_openai\provider']);
+
+        foreach ($records as $record) {
+            $actionconfig = json_decode($record->actionconfig, true, 512);
+            $originalactionconfig = $actionconfig;
+
+            foreach ($actionconfig as $actionkey => $action) {
+                $model = $action['settings']['model'];
+                if ($model === 'gpt-4o' || $model === 'o1') {
+                    // Rename setting max_tokens to max_completion_tokens.
+                    if (isset($action['settings']['max_tokens'])) {
+                        $actionconfig[$actionkey]['settings']['max_completion_tokens'] = intval($action['settings']['max_tokens']);
+                        unset($actionconfig[$actionkey]['settings']['max_tokens']);
+                    }
+                }
+                // Cast settings for 'gpt-4o' model.
+                if ($model === 'gpt-4o') {
+                    if (isset($action['settings']['top_p'])) {
+                        $actionconfig[$actionkey]['settings']['top_p'] = floatval($action['settings']['top_p']);
+                    }
+                    if (isset($action['settings']['presence_penalty'])) {
+                        $actionconfig[$actionkey]['settings']['presence_penalty'] =
+                            floatval($action['settings']['presence_penalty']);
+                    }
+                    if (isset($action['settings']['frequency_penalty'])) {
+                        $actionconfig[$actionkey]['settings']['frequency_penalty'] =
+                            floatval($action['settings']['frequency_penalty']);
+                    }
+                }
+                // Remove settings from 'o1' model.
+                if ($model === 'o1') {
+                    if (isset($action['settings']['top_p'])) {
+                        unset($actionconfig[$actionkey]['settings']['top_p']);
+                    }
+                    if (isset($action['settings']['presence_penalty'])) {
+                        unset($actionconfig[$actionkey]['settings']['presence_penalty']);
+                    }
+                    if (isset($action['settings']['frequency_penalty'])) {
+                        unset($actionconfig[$actionkey]['settings']['frequency_penalty']);
+                    }
+                }
+            }
+
+            if ($originalactionconfig !== $actionconfig) {
+                $updatedrecord = new stdClass();
+                $updatedrecord->id = $record->id;
+                $updatedrecord->actionconfig = json_encode($actionconfig);
+                $DB->update_record('ai_providers', $updatedrecord);
+            }
+        }
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2025041401.08);
+    }
+
     return true;
 }
diff --git a/version.php b/version.php
index 7f17bcc6955..4291de57151 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2025041401.07;              // 20250414      = branching date YYYYMMDD - do not modify!
+$version  = 2025041401.08;              // 20250414      = branching date YYYYMMDD - do not modify!
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '5.0.1+ (Build: 20250725)';    // Human-friendly version name