> ## Documentation Index
> Fetch the complete documentation index at: https://arize-ax.mintlify.site/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Oh My Pi

> Trace Oh My Pi (omp) terminal coding sessions, model calls, tool usage, and token costs in Arize AX using the Arize Coding Harness Tracing.

> Trace Oh My Pi (omp) terminal coding sessions, model calls, tool usage, and token costs with Arize AX for full observability.

[Oh My Pi (omp)](https://github.com/can1357/oh-my-pi) is a terminal coding agent that loads its extensions in-process inside its Bun runtime. The [Arize Coding Harness Tracing](https://github.com/Arize-ai/coding-harness-tracing) instruments omp lifecycle events and exports [OpenInference](https://github.com/Arize-ai/openinference) spans to Arize AX. Each agent run is captured as a trace with model calls, tool invocations, and inline token usage.

## Launch Arize AX

To get started, sign up for a free [Arize AX account](https://app.arize.com/auth/join) and get your Space ID and API Key:

1. Log in at [app.arize.com](https://app.arize.com)
2. Click **Settings** and copy the **Space ID**
3. Open the **API Keys** tab and create or copy an API key

## Install

### Curl installer

**macOS / Linux:**

```bash theme={null}
curl -sSL https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.sh | bash -s -- omp
```

**Windows (PowerShell):**

```powershell theme={null}
iwr -useb https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.bat -OutFile $env:TEMP\install.bat
& $env:TEMP\install.bat omp
```

### Local clone

```bash theme={null}
git clone https://github.com/Arize-ai/coding-harness-tracing.git
cd coding-harness-tracing
./install.sh omp           # macOS / Linux
install.bat omp            # Windows
```

The installer prompts for your backend and project name, writes credentials to `~/.arize/harness/config.json`, copies the hook shim into `~/.omp/extensions/arize-tracing.ts`, and registers the shim's absolute path in the `extensions` array of `~/.omp/agent/settings.json`. omp does not auto-discover an extensions directory, so this explicit registration is required — the installer handles it for you.

Open a new omp session after install so the extension loads.

## Configuration

Credentials live in `~/.arize/harness/config.json`. Environment variables override values in `config.json` and can be set in your shell profile before launching omp.

```bash theme={null}
export ARIZE_API_KEY="<your-api-key>"
export ARIZE_SPACE_ID="<your-space-id>"
export ARIZE_PROJECT_NAME="omp"
export ARIZE_TRACE_ENABLED="true"
```

| Variable              | Purpose                                                                      |
| :-------------------- | :--------------------------------------------------------------------------- |
| `ARIZE_TRACE_ENABLED` | Toggle tracing on or off                                                     |
| `ARIZE_PROJECT_NAME`  | Destination project name (defaults to `omp`)                                 |
| `ARIZE_DRY_RUN`       | Run the hook without sending spans, for validation                           |
| `ARIZE_USER_ID`       | Attribute traces to a specific user                                          |
| `ARIZE_VERBOSE`       | Log routine handler activity (event dispatch, span emits, state transitions) |
| `ARIZE_TRACE_DEBUG`   | Dump raw event payloads under `~/.arize/harness/state/debug/` for inspection |

See the [main README's Environment variables section](https://github.com/Arize-ai/coding-harness-tracing#environment-variables) for the full list of runtime overrides.

### Redaction controls

Each `ARIZE_LOG_*` flag accepts `"true"` or `"false"` and defaults to `"true"`. Set to `"false"` to opt out per category:

```bash theme={null}
export ARIZE_LOG_PROMPTS="false"
export ARIZE_LOG_TOOL_DETAILS="false"
export ARIZE_LOG_TOOL_CONTENT="false"
```

| Flag                     | Redacts                                 |
| :----------------------- | :-------------------------------------- |
| `ARIZE_LOG_PROMPTS`      | User prompt and assistant response text |
| `ARIZE_LOG_TOOL_DETAILS` | Tool names and arguments                |
| `ARIZE_LOG_TOOL_CONTENT` | Tool call output content                |

## Observe

Once tracing is enabled, omp activity is streamed to Arize AX. There is one trace per **agent run** — a user prompt through the agent's internal turn/tool-use loop to its final answer. Each trace is a tree:

* **Turn traces** — the root span for each agent run, with the user prompt as input and the final assistant message as output
* **LLM spans** — one per model call in the loop, with model name, provider, prompt/completion/reasoning token counts, cache read/write tokens, and cost
* **Tool spans** — one per tool call, pairing the tool invocation with its result and recording name, input args, and output
* **Session grouping** — all runs from the same session grouped by `session.id`

Token usage is captured directly on each LLM span — omp surfaces cumulative usage inline on assistant messages, so prompt, completion, reasoning, cache, and cost values are available on every model call.

### Spans Captured

omp exposes rich, once-fired lifecycle events that already carry final, structured data. The Arize AX hook forwards a small whitelist of them and emits the following spans:

| Span           | Kind  | Description                                                                                                                            |
| :------------- | :---- | :------------------------------------------------------------------------------------------------------------------------------------- |
| `Turn`         | CHAIN | Root span for the agent run. Input is the user prompt (`before_agent_start`); output is the final assistant message.                   |
| `LLM: <model>` | LLM   | Child of `Turn`. One per `turn_end`, carrying model info, token counts, cache tokens, and cost.                                        |
| `<tool>`       | TOOL  | Child of `Turn`. One per tool result in a `turn_end`, paired with its originating tool call by id and recording input args and output. |

Lifecycle events forwarded: `before_agent_start`, `turn_end`, `agent_end`, and `session_shutdown`.

## Verifying tracing

Run any omp session as you normally would. omp loads the registered extension on startup and forwards lifecycle events to the Arize AX hook.

* Errors and handler stderr land in `~/.arize/harness/logs/omp.log`. Set `export ARIZE_VERBOSE=true` before launching omp to also see routine handler activity.
* Set `export ARIZE_TRACE_DEBUG=true` to dump the raw event payloads under `~/.arize/harness/state/debug/` for inspection.
* Confirm spans appear in your configured project in Arize AX.

## Reference

For the full list of environment variables, default file paths, and troubleshooting steps, see the [omp tracing README](https://github.com/Arize-ai/coding-harness-tracing/blob/main/tracing/omp/README.md).

## Uninstall

```bash theme={null}
curl -sSL https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.sh | bash -s -- uninstall omp
```

Uninstall removes the shim's path from the `extensions` array in `~/.omp/agent/settings.json`, deletes the hook file at `~/.omp/extensions/arize-tracing.ts` (only if it carries the Arize header marker, so your own extensions are left alone), and removes the `harnesses.omp` block from `~/.arize/harness/config.json`.

## Resources

<CardGroup>
  <Card icon="github" href="https://github.com/Arize-ai/coding-harness-tracing" title="Arize Coding Harness Tracing" horizontal />

  <Card icon="github" href="https://github.com/Arize-ai/openinference" title="OpenInference" horizontal />

  <Card icon="github" href="https://github.com/can1357/oh-my-pi" title="Oh My Pi" horizontal />
</CardGroup>