Gemini CLI

Trace Gemini CLI sessions, agent steps, model calls, and tool invocations in Arize AX using the Arize Coding Harness Tracing.

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

Gemini CLI is Google’s open-source command-line agent for Gemini. The Arize Coding Harness Tracing instruments Gemini CLI sessions and exports OpenInference spans to Arize AX.

Launch Arize AX

To get started, sign up for a free Arize AX account and get your Space ID and API Key:

1. Log in at 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:

curl -sSL https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.sh | bash -s -- gemini

Windows (PowerShell):

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

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 Arize AX credentials and 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.

export ARIZE_API_KEY="<your-api-key>"
export ARIZE_SPACE_ID="<your-space-id>"
export ARIZE_PROJECT_NAME="gemini"
export ARIZE_TRACE_ENABLED="true"

Redaction controls

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

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 Arize AX. You’ll see:

• Session traces — each session bracketed by SessionStart and SessionEnd
• Agent spans — paired BeforeAgent / AfterAgent events for each agent step
• LLM spans — paired BeforeModel / AfterModel events with model info and tokens
• Tool spans — paired BeforeTool / AfterTool events with input, output, and duration
• Session grouping — all spans from the same session grouped by session_id

Hooks Captured

Hook	Span Kind	Description
SessionStart	CHAIN	Session initialized
BeforeAgent	CHAIN	Agent step started, records input
AfterAgent	CHAIN	Agent step completed, records output
BeforeModel	LLM	Model call started, records prompt and model
AfterModel	LLM	Model call completed, records output and tokens
BeforeTool	TOOL	Tool invocation started, records name and input
AfterTool	TOOL	Tool invocation completed, records output and duration
SessionEnd	CHAIN	Session teardown, state file cleanup

Reference

For the full list of environment variables, default file paths, and troubleshooting steps, see the Gemini tracing README.

Uninstall

curl -sSL https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.sh | bash -s -- uninstall gemini

Resources

Arize Coding Harness Tracing

OpenInference

Gemini CLI