Setup Claude Code Tracing

Setup Tracing

Configure OpenInference tracing for Claude Code sessions or Agent SDK applications to Arize AX (cloud) or Phoenix (self-hosted).

How to Use This Skill

This skill follows a decision tree workflow. Start by asking the user where they are in the setup process:

1. Are they using the Claude Code CLI or the Agent SDK?

   • CLI → Continue to step 2
   • Agent SDK (Python or TypeScript) → Go to Agent SDK Setup

2. Do they already have credentials?

   • Yes → Jump to Configure Settings
   • No → Continue to step 3

3. Which backend do they want to use?

   • Phoenix (self-hosted) → Go to Set Up Phoenix
   • Arize AX (cloud) → Go to Set Up Arize AX

4. Are they troubleshooting?

   • Yes → Jump to Troubleshoot

Important: Only follow the relevant path for the user's needs. Don't go through all sections.

Set Up Phoenix

Phoenix is self-hosted and requires no Python dependencies for tracing.

Install Phoenix

Ask if they already have Phoenix running. If not, walk through:

# Option A: pip
pip install arize-phoenix && phoenix serve

# Option B: Docker
docker run -p 6006:6006 arizephoenix/phoenix:latest

Phoenix UI will be available at http://localhost:6006. Confirm it's running:

curl -sf http://localhost:6006/v1/traces >/dev/null && echo "Phoenix is running" || echo "Phoenix not reachable"

Then proceed to Configure Local Project with PHOENIX_ENDPOINT=http://localhost:6006.

Set Up Arize AX

Arize AX is available as a SaaS platform or as an on-prem deployment. Users need an account, a space, and an API key.

First, ask the user: "Are you using the Arize SaaS platform or an on-prem instance?"

• SaaS → Uses the default endpoint (otlp.arize.com:443). Continue below.
• On-prem → The user will need to provide their custom OTLP endpoint (e.g., otlp.mycompany.arize.com:443). Ask for it and note it for the Configure Settings step where it will be set as ARIZE_OTLP_ENDPOINT.

1. Create an account

If the user doesn't have an Arize account:

• SaaS: Sign up at https://app.arize.com/auth/join
• On-prem: Contact their administrator for access to the on-prem instance

2. Get Space ID and API key

Walk the user through finding their credentials:

1. Log in to their Arize instance (https://app.arize.com for SaaS, or their on-prem URL)
2. Click Settings (gear icon) in the left sidebar
3. The Space ID is shown on the Space Settings page
4. Go to the API Keys tab
5. Click Create API Key or copy an existing one

Both ARIZE_API_KEY and ARIZE_SPACE_ID are required.

3. Install Python dependencies

Arize AX uses gRPC, which requires Python:

pip install opentelemetry-proto grpcio

Verify:

python3 -c "import opentelemetry; import grpc; print('OK')"

Then proceed to Configure Settings. If the user is on an on-prem instance, remind them to set ARIZE_OTLP_ENDPOINT to their custom endpoint.

Configure Settings

Before configuring, ask the user:

"Do you want to configure tracing globally or for this project only?"

• Globally → ~/.claude/settings.json (applies to all projects)
• Project-local → .claude/settings.local.json (applies only to this project)

Recommendation: Use project-local for different backends per project (e.g., dev Phoenix vs prod Arize).

Ask the user for:

1. Scope (if not already determined): Global or project-local
2. Backend choice: Phoenix or Arize AX
3. Credentials:
   • Phoenix: endpoint URL (default: http://localhost:6006), optional API key
   • Arize AX: API key and Space ID
4. OTLP Endpoint (Arize AX only, optional): For hosted Arize instances using a custom endpoint. Defaults to otlp.arize.com:443 if not set.
5. Project name (optional): defaults to workspace name

Write the config

Determine the config file:

• Global: ~/.claude/settings.json
• Project-local: .claude/settings.local.json (create directory if needed: mkdir -p .claude)

Read the file (or create {} if it doesn't exist), then merge env vars into the "env" object.

Phoenix:

{
  "env": {
    "PHOENIX_ENDPOINT": "<endpoint>",
    "ARIZE_TRACE_ENABLED": "true"
  }
}

If the user has a Phoenix API key, also set "PHOENIX_API_KEY": "<key>".

Arize AX:

{
  "env": {
    "ARIZE_API_KEY": "<key>",
    "ARIZE_SPACE_ID": "<space-id>",
    "ARIZE_TRACE_ENABLED": "true"
  }
}

If the user has a custom OTLP endpoint (e.g., a hosted Arize instance), also set "ARIZE_OTLP_ENDPOINT": "<host:port>". Defaults to otlp.arize.com:443 if not set.

If a custom project name was provided, also set "ARIZE_PROJECT_NAME": "<name>".

If the user wants trace attribution by user, also set "ARIZE_USER_ID": "<user-id>". This adds user.id to all spans (OpenInference convention), enabling per-user filtering in Arize/Phoenix.

Example workflow:

# For project-local
mkdir -p .claude
echo '{}' > .claude/settings.local.json
# Then use jq or editor to add env vars

Validate

Phoenix: Run curl -sf <endpoint>/v1/traces >/dev/null to check connectivity. Warn if unreachable but note it may just not be running yet.

Arize AX: Run python3 -c "import opentelemetry; import grpc" to check dependencies. If it fails, tell the user to run pip install opentelemetry-proto grpcio.

Confirm

Tell the user:

• Configuration saved to the chosen file:
  • Global: ~/.claude/settings.json
  • Project-local: .claude/settings.local.json
• Restart the Claude Code session for tracing to take effect
• After restarting, traces will appear in their Phoenix UI or Arize AX dashboard under the project name
• Mention ARIZE_DRY_RUN=true to test without sending data
• Mention ARIZE_VERBOSE=true for debug output
• Logs are written to /tmp/arize-claude-code.log

Note: Project-local settings override global settings for the same variables.

Agent SDK Setup

For users building with the Claude Agent SDK (Python or TypeScript), the tracing plugin loads as a local plugin. This section provides code and configuration for the developer to add to their application — the agent cannot set this up at runtime since plugin paths and settings must be configured before the SDK session starts.

Important: The user must use ClaudeSDKClient — the standalone query() function does not support hooks, so tracing will not work with it.

How to guide the user

When a user asks about Agent SDK tracing setup, provide them with the steps below to integrate into their own code. Do NOT try to execute export commands or modify their application source — instead, give them the snippets to copy.

1. Choose a backend

Ask the user which backend they want. If they don't have credentials yet, walk them through Set Up Phoenix or Set Up Arize AX first, then return here.

2. Get the plugin path

Ask the user: "Have you already installed this plugin via the Claude Code CLI?"

If yes (already installed via CLI): They can reference it from the CLI cache. Tell them to check ~/.claude/plugins/installed_plugins.json for the exact path, or use:

~/.claude/plugins/cache/arize-claude-plugin/claude-code-tracing/1.0.0

If no: Tell them to clone the repo into their project:

git clone https://github.com/Arize-ai/arize-claude-code-plugin.git

The plugin path will be ./arize-claude-code-plugin/plugins/claude-code-tracing

For Arize AX, they also need Python dependencies:

pip install opentelemetry-proto grpcio

3. Create a settings file

The Agent SDK spawns a Claude Code subprocess that does not inherit the user's shell environment variables. Tracing credentials must be passed via a settings file referenced in the ClaudeAgentOptions.

Tell the user to create a settings.local.json file (or similar) with their tracing credentials:

Phoenix:

{
  "env": {
    "PHOENIX_ENDPOINT": "http://localhost:6006",
    "ARIZE_TRACE_ENABLED": "true"
  }
}

If the user has a Phoenix API key, also include "PHOENIX_API_KEY": "<key>".

Arize AX:

{
  "env": {
    "ARIZE_API_KEY": "your-api-key",
    "ARIZE_SPACE_ID": "your-space-id",
    "ARIZE_TRACE_ENABLED": "true"
  }
}

Optional env vars that can also be added to the settings file:

• ARIZE_OTLP_ENDPOINT: Custom OTLP gRPC endpoint for hosted Arize instances (default: otlp.arize.com:443)
• ARIZE_PROJECT_NAME: Custom project name (default: workspace directory name)
• ARIZE_USER_ID: User identifier for trace attribution (adds user.id to all spans)
• ARIZE_DRY_RUN: Set to "true" to test without sending data
• ARIZE_VERBOSE: Set to "true" for debug output

4. Add the plugin to their code

Give the user the appropriate snippet to add to their application. They must use ClaudeSDKClient and pass both the plugin path (from step 2) and the settings file (from step 3):

Python:

from claude_agent_sdk import ClaudeAgentOptions, ClaudeSDKClient

PLUGIN_PATH = "./arize-claude-code-plugin/plugins/claude-code-tracing"  # or CLI cache path

options = ClaudeAgentOptions(
    plugins=[{"type": "local", "path": PLUGIN_PATH}],
    settings="./settings.local.json",
)
async with ClaudeSDKClient(options=options) as client:
    await client.query("Your prompt here")
    async for message in client.receive_response():
        print(message)

TypeScript:

import { ClaudeSDKClient } from "@anthropic-ai/claude-agent-sdk";

const PLUGIN_PATH = "./arize-claude-code-plugin/plugins/claude-code-tracing"; // or CLI cache path

const client = new ClaudeSDKClient({
  plugins: [{ type: "local", path: PLUGIN_PATH }],
  settings: "./settings.local.json",
});

await client.connect();
await client.query("Your prompt here");
for await (const message of client.receiveResponse()) {
  console.log(message);
}
await client.close();

5. Validate

Tell the user to add "ARIZE_DRY_RUN": "true" to their settings file to verify hooks fire without sending data, and check /tmp/arize-claude-code.log for output.

Agent SDK Compatibility

• Important: You must use ClaudeSDKClient — the standalone query() function does not support hooks and tracing will not work.
• TypeScript SDK: All 9 hooks are supported — full parity with the CLI.
• Python SDK: SessionStart, SessionEnd, Notification, and PermissionRequest hooks are not available. The plugin handles this automatically — session state is lazily initialized on the first UserPromptSubmit. Core tracing (LLM spans, tool spans, subagent spans) works fully.
• Tracing credentials must be passed via a settings file in ClaudeAgentOptions — the SDK subprocess does not inherit shell environment variables.
• If the user is troubleshooting an existing Agent SDK setup, you can help by checking log files (/tmp/arize-claude-code.log), verifying the settings file contains the correct env vars, or enabling dry-run mode.

Troubleshoot

Common issues and fixes: