fix: tolerate markdown-fenced JSON from LLM responses (v0.4.3)

Models like GPT 5.1 Nano ignore response_format: json_object and wrap
their JSON in ```json fences or add preamble text. New Json_Extractor
utility tries: (1) direct decode, (2) strip markdown fences, (3) find
outermost { ... } substring. Applied to analyzer and chief editor
parsers. Raw response logged on parse failure for debugging.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,16 @@ All notable changes to PRAutoBlogger will be documented in this file.
 Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project uses [Semantic Versioning](https://semver.org/).
 
+## [0.4.3] — 2026-04-19
+
+### Fixed
+- **"Analysis response was not valid JSON" with some models.** Models like
+  GPT 5.1 Nano ignore `response_format: json_object` and wrap JSON in markdown
+  fences or preamble text. New `PRAutoBlogger_Json_Extractor` utility strips
+  fences and extracts the outermost JSON object. Applied to both the content
+  analyzer and chief editor parsers. Raw response now logged on failure for
+  debugging.
+
 ## [0.4.2] — 2026-04-19
 
 ### Fixed

includes/core/class-chief-editor.php

@@ -12,6 +12,7 @@ declare(strict_types=1);
  * Dependencies: LLM_Provider_Interface, Cost_Tracker.
  *
  * @see core/class-content-generator.php — Produces the content we review.
+ * @see core/class-json-extractor.php    — Tolerant JSON parsing for LLM output.
  * @see core/class-publisher.php         — Publishes approved content.
  * @see ARCHITECTURE.md                  — Data flow step 5.
  */
@@ -145,10 +146,11 @@ class PRAutoBlogger_Chief_Editor {
 	 * @return PRAutoBlogger_Editorial_Review
 	 */
 	private function parse_review_response( string $content ): PRAutoBlogger_Editorial_Review {
-		$data = json_decode( $content, true );
+		$data = PRAutoBlogger_Json_Extractor::decode( $content );
 
 		if ( ! is_array( $data ) || ! isset( $data['verdict'] ) ) {
 			PRAutoBlogger_Logger::instance()->error( 'Chief editor response was not valid JSON. Defaulting to rejected.', 'editor' );
+			PRAutoBlogger_Logger::instance()->debug( 'Raw editor response: ' . mb_substr( $content, 0, 500 ), 'editor' );
 			return new PRAutoBlogger_Editorial_Review( [
 				'verdict'       => 'rejected',
 				'notes'         => 'Editor response could not be parsed.',

includes/core/class-content-analyzer.php

@@ -15,6 +15,7 @@ declare(strict_types=1);
  * @see core/class-analysis-prompts.php       — System/user prompt builders + performance context.
  * @see providers/interface-llm-provider.php  — LLM used for analysis.
  * @see core/class-cost-tracker.php           — Logs API costs.
+ * @see core/class-json-extractor.php         — Tolerant JSON parsing for LLM output.
  * @see core/class-idea-scorer.php            — Consumes analysis results.
  * @see ARCHITECTURE.md                       — Data flow step 2.
  */
@@ -175,9 +176,10 @@ class PRAutoBlogger_Content_Analyzer {
 	 * @return PRAutoBlogger_Analysis_Result[]
 	 */
 	private function parse_analysis_response( string $content, array $source_items ): array {
-		$data = json_decode( $content, true );
+		$data = PRAutoBlogger_Json_Extractor::decode( $content );
 		if ( ! isset( $data['patterns'] ) || ! is_array( $data['patterns'] ) ) {
 			PRAutoBlogger_Logger::instance()->error( 'Analysis response was not valid JSON or missing patterns key.', 'analyzer' );
+			PRAutoBlogger_Logger::instance()->debug( 'Raw analysis response: ' . mb_substr( $content, 0, 500 ), 'analyzer' );
 			return [];
 		}
 

includes/core/class-json-extractor.php

@@ -0,0 +1,60 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Extracts valid JSON from potentially dirty LLM response strings.
+ *
+ * Many models ignore the `response_format: json_object` instruction and wrap
+ * their output in markdown fences, add preamble text, or append trailing
+ * commentary. This class strips all of that and returns clean decoded data.
+ *
+ * Triggered by: Any class that parses JSON from an LLM response.
+ * Dependencies: None (pure utility).
+ *
+ * @see core/class-content-analyzer.php — Uses this for analysis JSON parsing.
+ * @see core/class-chief-editor.php     — Uses this for editorial review JSON parsing.
+ */
+class PRAutoBlogger_Json_Extractor {
+
+	/**
+	 * Decode JSON from an LLM response, tolerating markdown fences and preamble.
+	 *
+	 * Attempts, in order:
+	 * 1. Direct json_decode (model returned clean JSON).
+	 * 2. Strip ```json ... ``` fences, then decode.
+	 * 3. Find the first `{` and last `}` and decode that substring.
+	 *
+	 * @param string $raw The raw LLM response content.
+	 * @return array<string, mixed>|null Decoded associative array, or null on failure.
+	 */
+	public static function decode( string $raw ): ?array {
+		$trimmed = trim( $raw );
+
+		// 1. Clean JSON — best case.
+		$decoded = json_decode( $trimmed, true );
+		if ( is_array( $decoded ) ) {
+			return $decoded;
+		}
+
+		// 2. Markdown-fenced JSON (```json ... ``` or ``` ... ```).
+		if ( preg_match( '/```(?:json)?\s*\n?(.*?)\n?\s*```/s', $trimmed, $matches ) ) {
+			$decoded = json_decode( trim( $matches[1] ), true );
+			if ( is_array( $decoded ) ) {
+				return $decoded;
+			}
+		}
+
+		// 3. Brute-force: find outermost { ... } substring.
+		$first_brace = strpos( $trimmed, '{' );
+		$last_brace  = strrpos( $trimmed, '}' );
+		if ( false !== $first_brace && false !== $last_brace && $last_brace > $first_brace ) {
+			$candidate = substr( $trimmed, $first_brace, $last_brace - $first_brace + 1 );
+			$decoded   = json_decode( $candidate, true );
+			if ( is_array( $decoded ) ) {
+				return $decoded;
+			}
+		}
+
+		return null;
+	}
+}

prautoblogger.php

@@ -8,7 +8,7 @@ declare(strict_types=1);
  * Plugin Name:       PRAutoBlogger
  * Plugin URI:        https://peptiderepo.com/prautoblogger
  * Description:       Monitors social media for trending topics, generates SEO-friendly blog posts using AI, and publishes them on a daily schedule with full cost tracking and self-improvement metrics.
- * Version:           0.4.2
+ * Version:           0.4.3
  * Requires at least: 6.0
  * Requires PHP:      7.4
  * Author:            PeptideRepo
@@ -35,7 +35,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 | and limits without magic strings.
 */
 
-define( 'PRAUTOBLOGGER_VERSION', '0.4.2' );
+define( 'PRAUTOBLOGGER_VERSION', '0.4.3' );
 define( 'PRAUTOBLOGGER_DB_VERSION', '1.1.0' );
 define( 'PRAUTOBLOGGER_PLUGIN_FILE', __FILE__ );
 define( 'PRAUTOBLOGGER_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );