diff --git a/server/modules/providers/list/claude/claude-session-synchronizer.provider.ts b/server/modules/providers/list/claude/claude-session-synchronizer.provider.ts
index 530e4328..9320a2fe 100644
--- a/server/modules/providers/list/claude/claude-session-synchronizer.provider.ts
+++ b/server/modules/providers/list/claude/claude-session-synchronizer.provider.ts
@@ -25,6 +25,21 @@ export class ClaudeSessionSynchronizer implements IProviderSessionSynchronizer {
   private readonly provider = 'claude' as const;
   private readonly claudeHome = path.join(os.homedir(), '.claude');
 
+  /**
+   * Returns true when a JSONL file is a subagent transcript rather than a
+   * top-level session.
+   *
+   * Claude stores subagent transcripts under a `subagents/` directory, e.g.
+   * `~/.claude/projects/<encoded-cwd>/<session-id>/subagents/agent-<id>.jsonl`.
+   * Those files repeat the parent session's `sessionId`, so indexing them as
+   * standalone sessions overwrites the parent row's `jsonl_path` and corrupts
+   * the main session record. The recursive scan in `synchronize()` reaches
+   * them, so both entry points must skip them.
+   */
+  private isSubagentTranscript(filePath: string): boolean {
+    return path.normalize(filePath).split(path.sep).includes('subagents');
+  }
+
   /**
    * Scans ~/.claude/projects and upserts discovered sessions into DB.
    */
@@ -38,6 +53,10 @@ export class ClaudeSessionSynchronizer implements IProviderSessionSynchronizer {
 
     let processed = 0;
     for (const filePath of files) {
+      if (this.isSubagentTranscript(filePath)) {
+        continue;
+      }
+
       const parsed = await this.processSessionFile(filePath, nameMap);
       if (!parsed) {
         continue;
@@ -66,6 +85,9 @@ export class ClaudeSessionSynchronizer implements IProviderSessionSynchronizer {
     if (!filePath.endsWith('.jsonl')) {
       return null;
     }
+    if (this.isSubagentTranscript(filePath)) {
+      return null;
+    }
 
     const nameMap = await buildLookupMap(path.join(this.claudeHome, 'history.jsonl'), 'sessionId', 'display');
     const parsed = await this.processSessionFile(filePath, nameMap);