Codex Trace Viewer

Codex Trace Viewer helps inspect local Codex session traces end-to-end: conversation metadata, token/context arc, timeline events, and detailed event payloads. Looks for Codex rollout traces in ~/.codex/sessions and ~/.codex/archived_sessions.

(Screenshot uses redacted local paths and identifiers.)

Run

cd /path/to/codex-trace-viewer
./run.sh

By default it starts at http://127.0.0.1:8123 and opens your browser with the most recent conversation selected.

Optional flags

./run.sh --port 9000
./run.sh --host 0.0.0.0 --no-open
./run.sh --codex-home /path/to/.codex

Security notes

• The server has no authentication and exposes local conversation content and metadata.
• Keep the default bind host 127.0.0.1 unless you intentionally want LAN access.
• If you bind to 0.0.0.0, place it behind trusted network controls.

Code quality

I make no claims about code quality. This app is entirely vibe coded with GPT-5.3-codex xhigh.

Dependencies

There are currently no external library dependencies (it's vanilla HTML/CSS/JS and Python standard library). There is one network call out to get a Google Font (Exo), which is not required.

The monospace font shown in the screenshot is MonoLisa, which I personally use and enjoy, but also has fallbacks. You can also just change it to your monospace font of choice.

Included script run.sh expects uv, but you can also run it with plain Python (python server.py --open).