> ## Documentation Index
> Fetch the complete documentation index at: https://arizeai-433a7140.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Gemini CLI

> Trace Gemini CLI sessions, agent steps, model calls, and tool invocations in Phoenix.

> Trace Gemini CLI sessions, agent steps, model calls, and tool invocations in Phoenix for full observability.

Trace your [Gemini CLI](https://github.com/google-gemini/gemini-cli) sessions in Phoenix with the [coding-harness-tracing](https://github.com/Arize-ai/coding-harness-tracing) toolkit — every turn shows up as a trace with the model call, each tool it runs, and token usage, grouped into its session. No application code changes required: the toolkit hooks into Gemini CLI's lifecycle events and streams [OpenInference](https://github.com/Arize-ai/openinference) spans to Phoenix.

## Launch Phoenix

The fastest way to get started with Phoenix is by signing up for a [free Phoenix Cloud account](https://app.arize.com/auth/phoenix/signup). If you prefer, you can also run Phoenix in a [notebook](/docs/phoenix/environments#notebooks), [self-host it](/docs/phoenix/environments#container), or use it directly from your [terminal](/docs/phoenix/environments#terminal).

Go to the settings page in your Phoenix instance to find your **endpoint** and **API key**. A self-hosted Phoenix defaults to `http://localhost:6006`; the API key is only required when auth is enabled.

## Install

The **curl installer** is the simplest — it runs a short wizard that saves your Phoenix credentials for you. Use a **local clone** if you'd rather run the installer from a checkout of the source.

### Curl installer (recommended)

**macOS / Linux:**

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

**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 gemini
```

### Local clone

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

The installer prompts for your backend — select **Phoenix**, then enter your endpoint and optional API key — and your project name, writes them to `~/.arize/harness/config.json`, and registers the hooks in `~/.gemini/settings.json`.

## Configuration

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

```bash theme={null}
export PHOENIX_ENDPOINT="http://localhost:6006"
export PHOENIX_API_KEY="<your-api-key>"   # optional, only if auth is enabled
export PHOENIX_PROJECT="gemini"
export ARIZE_TRACE_ENABLED="true"
```

On the Phoenix backend, set the project name with `PHOENIX_PROJECT` (or `PHOENIX_PROJECT_NAME`); `ARIZE_PROJECT_NAME` is Arize-only and ignored here. `ARIZE_TRACE_ENABLED` is a backend-agnostic harness setting and keeps the `ARIZE_` prefix regardless of destination.

### 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, Gemini CLI activity is streamed to Phoenix. You'll see:

* **Turn traces** — each agent turn as a `Turn` (CHAIN) span, with the prompt as input and the final response as output
* **LLM spans** — one `LLM: <model>` span per model call, with model name and token counts
* **Tool spans** — one per tool call (`read_file`, `run_shell_command`, and others), with input, output, and duration
* **Session grouping** — all turns from the same session grouped by `session_id`

## Reference

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

## Uninstall

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

## 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="book-open" href="https://github.com/google-gemini/gemini-cli" title="Gemini CLI" horizontal />
</CardGroup>