agent-trace for VS Code
Live session overlay for agent-trace. Shows what your agent is doing without leaving the editor.
Features
Status bar — cost, tool call count, and active tool name, updated on every event. Click to open the event stream panel.
$(pulse) agent $0.0042 47 calls [Read]
Gutter annotations — files the agent has read or modified get a colored left border and inline label:
src/auth/middleware.ts ← agent read 3×, modified 1× this session
src/db/schema.ts ← agent read 1× this session
Event stream panel — live feed of every tool call, file op, LLM request, and error in the Explorer sidebar. Same information as agent-strace watch but in the editor.
Pause button — stop the agent mid-session without killing it. Writes a signal file that agent-strace watch picks up and sends SIGSTOP to the agent process. Resume resumes it.
Requirements
- agent-trace installed (
pip install agent-strace or uv tool install agent-strace)
- A session started via
agent-strace setup (Claude Code hooks) or agent-strace record (MCP proxy)
The extension activates automatically when a .agent-traces/ directory exists in the workspace root.
Usage
- Install agent-trace and set up hooks:
agent-strace setup # adds hooks to .claude/settings.json
- Open your project in VS Code / Cursor.
- Start Claude Code — the status bar item appears as soon as the session starts.
- Open the Agent Trace panel in the Explorer sidebar for the full event stream.
The Pause button in the panel (or agent-trace: Pause Agent command) sends SIGSTOP to the agent. This requires agent-strace watch to be running in a terminal alongside the session.
Configuration
| Setting |
Default |
Description |
agentTrace.traceDir |
.agent-traces |
Path to trace store, relative to workspace root |
agentTrace.showGutterAnnotations |
true |
Gutter icons on agent-touched files |
agentTrace.showInlineText |
true |
Inline read/write counts at top of file |
How it works
The extension watches .agent-traces/.active-session for the current session ID, then tails events.ndjson for new events using fs.watch. No polling when idle. No network calls. No new processes.
Pause works by writing .agent-traces/.pause-request — agent-strace watch checks for this file on every poll cycle and sends SIGSTOP / SIGCONT to the agent PID.
