Modify our excerpt prompt a bit more, trying to ensure the summary ge…

…nerated pairs well with the title. Exclude the title from the content we summarize. Increase temperature value

includes/Classifai/Providers/OpenAI/ChatGPT.php

@@ -557,7 +557,7 @@ public function generate_excerpt( int $post_id = 0, array $args = [] ) {
 		 *
 		 * @return {string} Prompt.
 		 */
-		$prompt = apply_filters( 'classifai_chatgpt_excerpt_prompt', 'Provide a teaser for the following text using a maximum of ' . $excerpt_length . ' words', $post_id, $excerpt_length );
+		$prompt = apply_filters( 'classifai_chatgpt_excerpt_prompt', sprintf( 'Summarize the following message using a maximum of %d words. Ensure this summary pairs well with the following text: %s.', $excerpt_length, get_the_title( $post_id ) ), $post_id, $excerpt_length );
 
 		/**
 		 * Filter the request body before sending to ChatGPT.
@@ -575,12 +575,16 @@ public function generate_excerpt( int $post_id = 0, array $args = [] ) {
 			[
 				'model'       => $this->chatgpt_model,
 				'messages'    => [
+					[
+						'role'    => 'system',
+						'content' => $prompt,
+					],
 					[
 						'role'    => 'user',
-						'content' => $prompt . ': ' . $this->get_content( $post_id, $excerpt_length, true, $args['content'] ) . '',
+						'content' => $this->get_content( $post_id, $excerpt_length, false, $args['content'] ) . '',
 					],
 				],
-				'temperature' => 0,
+				'temperature' => 0.9,
 			],
 			$post_id
 		);
@@ -731,10 +735,10 @@ public function get_content( int $post_id = 0, int $return_length = 0, bool $use
 		/**
 		 * We then subtract those tokens from the max number of tokens ChatGPT allows
 		 * in a single request, as well as subtracting out the number of tokens in our
-		 * prompt (13). ChatGPT counts both the tokens in the request and in
+		 * prompt (~50). ChatGPT counts both the tokens in the request and in
 		 * the response towards the max.
 		 */
-		$max_content_tokens = $this->max_tokens - $return_tokens - 13;
+		$max_content_tokens = $this->max_tokens - $return_tokens - 50;
 
 		if ( empty( $post_content ) ) {
 			$post         = get_post( $post_id );