codex-usage-epd

Push your OpenAI Codex usage statistics to a 4.2" 400x300 three-colour e-paper display powered by the EPD-nRF5 firmware.

Features

• Plan quota: 5-hour + weekly windows (used / remaining %, reset time)
• "Tokens used today": a Total across all models, plus the top three models with bars proportional to the most-used model
• Optional "Last 7 days" line chart for the seven completed local calendar days before today, with dates and compact K/M/B totals. Enable render.show_history or pass --show-history to place the chart beside today's usage
• Credits balance when present on the plan
• Red alert bars when remaining % drops below render.warn_threshold
• --selftest verifies RLE + bitplane round-trips without network/hardware

Requirements

• macOS (BLE via bleak/CoreBluetooth), Python 3.10+
• ChatGPT login for Codex (~/.codex/auth.json with tokens.access_token)
• 4.2" 400x300 B/W/R panel with SSD1683/SSD1619 driver, model id 0x02

Install with a coding agent

Copy and paste this prompt into Codex or another coding agent:

Install https://github.com/hunterMG/codex-usage-epd on this computer. Read the
README first, check that the prerequisites are available, clone the repository
into an appropriate user directory, install its dependencies with uv, generate
the configuration file, and run the self-test. Do not print, copy, or modify my
Codex authentication token. Tell me what configuration still needs my input,
and ask for confirmation before installing or starting the launchd background
agent.

Setup

Clone this repo and cd to it in terminal.

uv sync --locked                     # creates .venv, installs deps + the package (editable)
uv run codex-usage-epd --init        # generate config/codex_usage_epd.yaml from the template
# edit config/codex_usage_epd.yaml (set ble.device etc.)
uv run codex-usage-epd --selftest    # render preview.png, no net/BLE
uv run codex-usage-epd --dry-run     # live fetch + render preview.png

Usage

uv run codex-usage-epd --init          # generate a config from the template
uv run codex-usage-epd --selftest      # sample data, verify encode/decode
uv run codex-usage-epd --dry-run       # fetch + render preview.png (no BLE)
uv run codex-usage-epd --probe         # connect + INIT, print device config/mtu
uv run codex-usage-epd --test-screen   # INIT + CLEAR full refresh (firmware check)
uv run codex-usage-epd --once          # fetch + render + push to display
uv run codex-usage-epd --loop          # push every N minutes forever

Modifiers (combine with the actions above):

--config <path>    # use this YAML config instead of the default
--force            # with --init: overwrite an existing config
--font <path>      # override render.font
--sample           # use synthetic sample data (no network)
--debug            # also dump raw wham/usage JSON to tmp/usage_dump.json

Config resolution when --config is not given: repo config/codex_usage_epd.yaml, then ~/.config/codex-usage-epd/codex_usage_epd.yaml, then the bundled template.

ble.device accepts auto (scans for NRF_EPD), a MAC address, or a name substring.

Installing as a package

Not published to PyPI yet. Install from the locally built wheel:

uv build                              # builds sdist + wheel into dist/
uv pip install dist/*.whl             # or: uv pip install --python <venv> dist/*.whl

The config template lives at config/codex_usage_epd.yaml.example. Run codex-usage-epd --init to generate a real config (~/.config/codex-usage-epd/ when installed, config/ in a checkout), or point at your own with --config /path/to/codex_usage_epd.yaml.

launchd (every 60 minutes)

./deploy/install.sh    # fills the __REPO__ placeholder with the checkout path
                       # and bootstraps the agent (works for any username)

This generates ~/Library/LaunchAgents/com.codex-usage-epd.plist from deploy/com.codex-usage-epd.plist.in, so no manual path editing is needed. To remove the agent later:

launchctl bootout gui/$(id -u)/com.codex-usage-epd
rm ~/Library/LaunchAgents/com.codex-usage-epd.plist

Configuration

Generate a config with codex-usage-epd --init, then edit config/codex_usage_epd.yaml (or ~/.config/codex-usage-epd/ when installed). Notable keys:

• display.width / display.height - panel pixels (400x300); display.model_id - EPD panel model id (0x02 for SSD1619 400x300 BWR)
• display.sleep_after_push - send the SLEEP command after pushing (default false; early sleep aborts the panel refresh)
• ble.device - auto | MAC address | name substring
• ble.scan_timeout - seconds per scan attempt; ble.scan_retries - retry the scan before giving up (missed advertisements)
• ble.interleave - writes per response-ack, mirrors the web client (50)
• ble.pacing_ms - delay between writes (0.0 = back-to-back)
• ble.hold_after_refresh - seconds to stay connected so the panel refresh completes (20)
• ble.slot - which image slot to write on the epdiy.cn slot firmware (0..N-1); "auto" picks the first free slot so an existing slot is never overwritten; -1/"none" disables the SET_SLOT command (plain EPD-nRF5 firmware)
• codex.auth_file - where the OAuth tokens live (default ~/.codex/auth.json)
• codex reads chatgpt_base_url from ~/.codex/config.toml if set
• render.font - .ttf path (auto-detected on macOS/Windows/Linux otherwise)
• render.warn_threshold - remaining % that turns a bar red
• render.preview - filename for the rendered preview PNG
• render.show_history - show the "Last 7 days" chart (default false); override with --show-history or --no-show-history, including in --selftest
• schedule.interval_minutes - interval used by --loop; launchd uses the fixed StartInterval in deploy/com.codex-usage-epd.plist.in

Notes

• Tokens are read from ~/.codex/auth.json and never logged or committed.
• The display must be powered (USB). With ble.patch_wakeup_pin: true it forces the device config byte to 0xFF so the panel keeps re-advertising after the timeout, letting the scheduled push always connect.

Development

uv sync --locked
uv run pre-commit install
uv run pre-commit run --all-files

License

GNU AGPL v3.0 or later — see LICENSE.