fix: repair function now removes API Error messages from sessions (v0.8.13)

When switching API providers, stale API Error assistant messages corrupt
the conversation context causing "unexpected end of JSON input" 400 errors
on resume. The repair function now strips these error lines along with
their associated retry attempts and scaffolding lines.

Author: Myoontyee

package.json

@@ -2,7 +2,7 @@
   "name": "claude-code-exporter",
   "displayName": "Claude Code Exporter — Claude Code, Codex & Cursor Conversation History",
   "description": "Export AI coding agent conversations to Markdown. Supports Claude Code (→ .claude-code-history/), OpenAI Codex (→ .codex-history/), and Cursor Composer (→ .cursor-history/). Features: auto-watch, session inject/import for claude --resume, and repair of thinking-block signature errors when switching API providers.",
-  "version": "0.8.12",
+  "version": "0.8.13",
   "publisher": "myoontyee",
   "engines": {
     "vscode": "^1.85.0"

src/extension.ts

@@ -1141,11 +1141,13 @@ function updateStatusBar(
 }
 
 // ─── Thinking-signature repair ─────────────────────────────────────────────────
-// Fixes four classes of provider-compatibility errors:
+// Fixes five classes of provider-compatibility errors:
 // 1. thinking blocks → text blocks (removes signature, converts type)
 // 2. model names with "-thinking" suffix → strip suffix
 // 3. misplaced tool_results — parallel tool_use results that landed in wrong turn
 // 4. orphaned tool_use blocks (no matching tool_result anywhere) → inject synthetic
+// 5. API Error messages — remove assistant lines containing "API Error:" text
+//    (these corrupt the conversation context and cause 400 errors on resume)
 
 function repairThinkingSignatures(jsonlPath: string): number {
   const raw = fs.readFileSync(jsonlPath, 'utf8');
@@ -1185,6 +1187,106 @@ function repairThinkingSignatures(jsonlPath: string): number {
     try { return JSON.parse(line) as Record<string, unknown>; } catch { return null; }
   });
 
+  // Pass 0: mark API Error assistant messages for removal
+  // These contain raw HTTP error JSON that corrupts context on resume
+  const removedIndices = new Set<number>();
+  for (let i = 0; i < parsed.length; i++) {
+    const obj = parsed[i];
+    if (!obj) continue;
+    const role = (obj.message as Record<string, unknown> | undefined)?.role;
+    if (role !== 'assistant') continue;
+    const content = (obj.message as Record<string, unknown>).content;
+    // Check if ALL blocks are API Error text
+    if (Array.isArray(content)) {
+      const allApiError = content.length > 0 && content.every((b: Record<string, unknown>) =>
+        b.type === 'text' && typeof b.text === 'string' && (b.text as string).startsWith('API Error:')
+      );
+      if (allApiError) {
+        removedIndices.add(i);
+        fixed++;
+      }
+    } else if (typeof content === 'string' && content.startsWith('API Error:')) {
+      removedIndices.add(i);
+      fixed++;
+    }
+  }
+
+  // Also remove file-history-snapshot and queue-operation lines that are
+  // adjacent to (immediately before/after) removed API error lines,
+  // as they are part of the failed turn
+  for (const idx of [...removedIndices]) {
+    // Look backward: remove preceding file-history-snapshot, custom-title, queue-operation
+    for (let j = idx - 1; j >= 0; j--) {
+      const o = parsed[j];
+      if (!o) continue;
+      const t = o.type as string;
+      if (t === 'file-history-snapshot' || t === 'custom-title' || t === 'queue-operation') {
+        removedIndices.add(j);
+      } else {
+        break;
+      }
+    }
+    // Look forward: remove following queue-operation, custom-title
+    for (let j = idx + 1; j < parsed.length; j++) {
+      const o = parsed[j];
+      if (!o) continue;
+      const t = o.type as string;
+      if (t === 'queue-operation' || t === 'custom-title') {
+        removedIndices.add(j);
+      } else {
+        break;
+      }
+    }
+  }
+
+  // Remove duplicate user messages that precede API errors
+  // Pattern: user says X → API Error → user says X again → API Error again
+  // Keep only the last user attempt
+  for (let i = 0; i < parsed.length; i++) {
+    if (removedIndices.has(i)) continue;
+    const obj = parsed[i];
+    if (!obj) continue;
+    const role = (obj.message as Record<string, unknown> | undefined)?.role;
+    if (role !== 'user') continue;
+    // Check if the next non-removed assistant line is an API Error (already removed)
+    let nextAssistantRemoved = false;
+    for (let j = i + 1; j < parsed.length; j++) {
+      const nxt = parsed[j];
+      if (!nxt) continue;
+      const nxtRole = (nxt.message as Record<string, unknown> | undefined)?.role;
+      if (nxtRole === 'assistant') {
+        if (removedIndices.has(j)) nextAssistantRemoved = true;
+        break;
+      }
+      if (nxt.type === 'user' || nxtRole === 'user') break;
+    }
+    if (nextAssistantRemoved) {
+      removedIndices.add(i);
+      // Also remove file-history-snapshot before this user line
+      for (let j = i - 1; j >= 0; j--) {
+        const o = parsed[j];
+        if (!o) continue;
+        const t = o.type as string;
+        if (t === 'file-history-snapshot' || t === 'queue-operation') {
+          removedIndices.add(j);
+        } else {
+          break;
+        }
+      }
+      // And after
+      for (let j = i + 1; j < parsed.length; j++) {
+        const o = parsed[j];
+        if (!o) continue;
+        const t = o.type as string;
+        if (t === 'file-history-snapshot') {
+          removedIndices.add(j);
+        } else {
+          break;
+        }
+      }
+    }
+  }
+
   // Pass 1: fix thinking blocks and model names
   for (let i = 0; i < parsed.length; i++) {
     const obj = parsed[i];
@@ -1259,6 +1361,7 @@ function repairThinkingSignatures(jsonlPath: string): number {
   // Pass 3: find truly orphaned tool_use (no tool_result anywhere), inject synthetic
   const resultLines: string[] = [];
   for (let i = 0; i < parsed.length; i++) {
+    if (removedIndices.has(i)) continue; // skip API Error lines and their scaffolding
     const obj = parsed[i];
     resultLines.push(obj ? JSON.stringify(obj) : lines[i]);
     if (!obj || getRole(obj) !== 'assistant') continue;