Code OSS Logs

Find and display logs from the most recent Code OSS or Agents app dev run.

Log Root Directories

If Code OSS was launched with --user-data-dir=<dir>, use <dir>/logs/ instead of the defaults above. Launch and debugging helpers often create temporary user data dirs under .build/; always prefer the exact user data dir from the launch command when it is known.

Each run creates a timestamped folder like 20260330T163430. The most recent folder sorted by modification time is usually the one the user cares about.

Procedure

1. Identify which app the user is asking about: Code OSS or Agents app. If unclear, check both.
2. Find the most recent log folder:

   ls -lt "$HOME/.vscode-oss-dev/logs" | head -5
   # or for a custom user data dir:
   ls -lt "<user-data-dir>/logs" | head -5
   

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3. Navigate into the most recent folder and list contents.
4. Read the relevant log file(s) based on what the user is investigating. Use tail for recent entries or rg to filter.

Directory Layout

Each timestamped log folder has this structure:

<timestamp>/
├── main.log                    # Electron main process (app lifecycle, window management)
├── agenthost.log               # Agent host process (Copilot agent, model listing, agent sessions)
├── mcpGateway.log              # MCP gateway/server coordination
├── sharedprocess.log           # Shared process (extensions gallery, global services)
├── telemetry.log               # Telemetry events
├── terminal.log                # Terminal/pty activity
├── ptyhost.log                 # Pty host process
├── network-shared.log          # Shared network activity
├── editSessions.log            # Edit sessions / cloud changes
├── userDataSync.log            # Settings sync
├── remoteTunnelService.log     # Remote tunnel service
│
└── window1/                    # Per-window logs (window1, window2, etc.)
    ├── renderer.log            # Renderer process (workbench UI, services, startup)
    ├── network.log             # Per-window network activity
    ├── views.log               # View/panel activity
    ├── notebook.rendering.log  # Notebook rendering
    ├── customizationsDebug.log # Agent customizations debug info (Agents app)
    ├── mcpServer.*.log         # Per-MCP-server logs (one file per configured server)
    │
    ├── exthost/                # Extension host logs
    │   ├── exthost.log         # Extension host main log (activation, errors)
    │   ├── extHostTelemetry.log
    │   ├── <publisher.extension>/  # Per-extension log folders
    │   │   └── <extension>.log
    │   └── output_logging_<timestamp>/  # Extension output channels
    │
    └── output_<timestamp>/     # Output channel logs (workbench side)
        ├── tasks.log           # Tasks output
        ├── agentSessionsOutput.log  # Agent sessions output (Agents app)
        └── agenthost.<clientId>.log  # Agent host IPC traffic when tracing is enabled

Multiple output_ Folders

A new output_<timestamp>/ folder and a corresponding output_logging_<timestamp>/ inside exthost/ is created each time the window reloads within the same session. The session-level timestamped folder, such as 20260330T163430/, stays the same, but each reload gets fresh output channel directories. The most recent output_* folder by timestamp has the logs for the current or latest reload. Earlier folders contain logs from prior reloads in that session.

Cloud Sandbox Startup Failures

Start with renderer.log. [CloudSandboxApi] connect/reconnect HTTP failures record status, elapsed time, environment/session/client IDs when available, and a validated requestId from X-GitHub-Request-Id. Use that request ID to correlate the exact upstream HTTP request; environment/session IDs also span retries and asynchronous work. A missing request ID may reflect an absent or browser-inaccessible response header.

Follow the returned clientId through [WebPubSubRelayTransport] and [RemoteAgentHostProtocol]. Relay readiness, the first publish acknowledgment, the first host frame, and the AHP initialize request/completion distinguish relay setup from host responsiveness. A relay publish acknowledgment does not prove host execution. The relay closing summary includes outstanding acknowledgments, host-frame/message counts, host silence, and protocol/reassembly error counts without logging credentials or payloads. These records are ordinary log-service output and do not require AHP payload logging.

Key Files by Use Case

Useful Commands

# Recent entries from a log file
tail -50 "<timestamp>/window1/renderer.log"

# Search all logs in a run for a probe marker or error
rg -n "MY_PROBE|error" "<timestamp>"

# Show non-empty logs in a run
find "<timestamp>" -type f -size +0 -print

Temporary Console Forwarding Workflow

When using temporary console.log probes and you need those probes to persist in the normal log files, enable dev console forwarding locally before launching Code OSS.

1. In src/vs/platform/log/common/log.ts, find isDevConsoleLogForwardingEnabled.
2. Temporarily enable the commented Boolean("true") line:

   export const isDevConsoleLogForwardingEnabled = false
       || Boolean("true") // done "weirdly" so that a lint warning prevents you from pushing this
       ;
   

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3. Build or let the watch task pick up the change.
4. Launch Code OSS or the Agents app and reproduce the issue.
5. Read the relevant logs.
6. Before finishing, restore the flag to its default-off state and remove every temporary console.log probe.

The Boolean("true") form is intentionally lint-hostile so an accidentally enabled flag should be caught before check-in. Do not check in this flag enabled.

Tips

• For temporary dev probes in source builds, either console.log or ILogService is fine. Use whichever is easiest in the code you are touching.
• console.log probes must never be checked in. If logging code is intended to stay in the product, use ILogService instead.
• If dev console forwarding is enabled in the source build, console.debug, console.error, console.info, console.log, and console.warn are written through the process log service into the normal log files.
• Console probes land in the log for the process that emitted them: main process in main.log, renderer/workbench in window1/renderer.log, shared process in sharedprocess.log, pty host in ptyhost.log, and agent host in agenthost.log. Extension host console output is observed from the renderer side and appears in window1/renderer.log when forwarding all extension-host console output is enabled.
• If console forwarding is not enabled, use ILogService for probes that must persist in the log files; native console.log may only appear in DevTools or stdout.
• Not all log files have content. Many are created empty and only populated if that subsystem produces output.
• window1/ is the first window; multi-window sessions will have window2/, etc.
• Log lines follow the format: YYYY-MM-DD HH:MM:SS.mmm [level] message.