Bug: VS Code Extension Sessions Not Registered in history.jsonl, Breaking /resume Cross-Environment

Bug: VS Code Extension Sessions Not Registered in history.jsonl, Breaking /resume Cross-Environment

Description

Sessions created by the Claude Code VS Code extension are not registered in ~/.claude/history.jsonl. Since the /resume command uses history.jsonl as its session index, these sessions are invisible to /resume — both in the VS Code integrated terminal and in external terminals.

This means users cannot resume VS Code extension sessions from any environment, and the /resume experience is inconsistent across execution contexts of the same tool.

Environment

• OS: Windows 10/11 (MSYS_NT-10.0-26200)
• Claude Code CLI version: Latest (as of 2025-02-10)
• VS Code Extension: anthropic.claude-code-2.1.38-win32-x64
• Shell: Git Bash (MSYS2)

Steps to Reproduce

1. Open a project folder in VS Code
2. Start a conversation using the Claude Code VS Code extension (sidebar panel)
3. Have a multi-turn conversation and close it
4. Open VS Code integrated terminal in the same project folder
5. Run claude (or cc) and type /resume
6. Result: "No conversations found to resume"
7. Open an external terminal, cd to the same project folder
8. Run claude and type /resume
9. Result: Same — the VS Code extension session is not listed

Expected Behavior

All sessions created in any execution environment (CLI, VS Code extension, VS Code terminal) should be visible and resumable via /resume, regardless of which environment is used to resume.

Actual Behavior

• CLI sessions (claude from terminal): Properly registered in history.jsonl and resumable via /resume ✅
• VS Code extension sessions: Session .jsonl files are created in ~/.claude/projects/<encoded-cwd>/ but NOT registered in history.jsonl ❌
• VS Code terminal sessions: May also be affected by inherited environment variables (CLAUDECODE=1, CLAUDE_CODE_ENTRYPOINT=claude-vscode)

Root Cause Analysis

Through investigation of the session storage system, I identified the following:

1. Session Storage Architecture

• Sessions are stored as .jsonl files in ~/.claude/projects/<encoded-cwd>/
• Path encoding: cwd.replace(/[^a-zA-Z0-9]/g, "-")
• history.jsonl serves as the central index for the /resume command

2. The Bug

The VS Code extension creates session .jsonl files in the correct project folder, but never writes an entry to history.jsonl. The /resume command exclusively reads history.jsonl to list available sessions, so VS Code extension sessions are invisible.

3. Evidence

In my project folder, I found:

• 4 session .jsonl files in the project's session directory
• Only 1 of these was registered in history.jsonl (created by CLI claude)
• 3 orphaned sessions created by the VS Code extension — completely invisible to /resume

Verified by examining the extension source (extension.js):

• The encoding function Zz(v) correctly computes the project folder path
• The spawnClaude function sets cwd from the workspace folder
• But no code path writes to history.jsonl after session creation

Impact

• Session continuity broken: Users cannot resume VS Code extension sessions
• Cross-environment workflow broken: Users who switch between VS Code and terminal lose access to prior sessions
• Data exists but is inaccessible: Session files are properly saved but not indexed

Suggested Fix

When the VS Code extension creates or completes a session, it should append an entry to ~/.claude/history.jsonl with the same format used by the CLI:

{
  "display": "<first user message or session title>",
  "pastedContents": {},
  "timestamp": <epoch_ms>,
  "project": "<workspace folder path>",
  "sessionId": "<session-uuid>"
}

This would make all sessions uniformly discoverable by /resume regardless of the execution environment.

Workaround

A manual sync script can scan session files and register orphaned sessions in history.jsonl:

// Scan ~/.claude/projects/*/*.jsonl and register missing sessions in history.jsonl
const fs = require('fs');
const path = require('path');
const claudeDir = path.join(require('os').homedir(), '.claude');
const histPath = path.join(claudeDir, 'history.jsonl');
const projectsDir = path.join(claudeDir, 'projects');

// Read existing history
const existing = new Set();
if (fs.existsSync(histPath)) {
  for (const line of fs.readFileSync(histPath, 'utf-8').trim().split('\n')) {
    try { existing.add(JSON.parse(line).sessionId); } catch {}
  }
}

// Scan all project session files
for (const proj of fs.readdirSync(projectsDir)) {
  const projDir = path.join(projectsDir, proj);
  if (!fs.statSync(projDir).isDirectory()) continue;
  for (const file of fs.readdirSync(projDir).filter(f => f.endsWith('.jsonl'))) {
    const sessionId = file.replace('.jsonl', '');
    if (existing.has(sessionId)) continue;
    // Extract first user message as display title
    const lines = fs.readFileSync(path.join(projDir, file), 'utf-8').trim().split('\n');
    let display = 'Untitled';
    for (const l of lines) {
      try {
        const d = JSON.parse(l);
        if (d.type === 'human' || d.role === 'user') {
          display = (d.message?.content || d.content || '').slice(0, 80);
          break;
        }
      } catch {}
    }
    const stat = fs.statSync(path.join(projDir, file));
    const entry = { display, pastedContents: {}, timestamp: stat.mtimeMs, project: proj, sessionId };
    fs.appendFileSync(histPath, JSON.stringify(entry) + '\n');
  }
}

Related

This may also affect other IDE integrations (JetBrains, etc.) if they use the same session creation path as the VS Code extension.