pi-phoenix

Phoenix tracing extension for pi. It sends OpenInference traces to Arize Phoenix so you can inspect pi sessions, system prompts, model calls, tool schemas, provider request payloads, and tool executions.

Why Arize?

Single binary + postgres. No ElasticSearch, no Kafka, no distributed tracing infrastructure to manage. Self-host in one container, or use the cloud offering.

Screenshots

Session overview

Trace detail

Trace model

pi.session
├── Turn 1: describe the bug...
│   ├── anthropic/claude-sonnet-4
│   ├── read
│   └── bash
├── Turn 2: fix it
│   ├── anthropic/claude-sonnet-4
│   └── edit
└── ...

• pi.session: one root session context
• Turn n: one span per agent run
• llm: one span per assistant/model response
• tool: one span per tool execution

Install with pi

npm

pi install npm:pi-phoenix

GitHub

pi install github:philipbjorge/pi-phoenix

Local checkout

pi install /home/phil/src/pi-phoenix

Usage

Local Phoenix

docker run -d -p 6006:6006 arizephoenix/phoenix:latest
pi -e /home/phil/src/pi-phoenix/index.ts

Phoenix Cloud

export PHOENIX_COLLECTOR_ENDPOINT=https://app.phoenix.arize.com
export PHOENIX_API_KEY=your-api-key
export PI_PHOENIX_PROJECT=my-project
pi -e /home/phil/src/pi-phoenix/index.ts

Configuration

| Variable | Default | Description | | --- | --- | --- | | PI_PHOENIX_ENABLE | true | Enable or disable tracing | | PI_PHOENIX_PROJECT | git repo root basename or cwd basename | Project name shown in Phoenix | | PHOENIX_COLLECTOR_ENDPOINT | http://localhost:6006 | Phoenix server URL | | PHOENIX_API_KEY | unset | API key for Phoenix Cloud | | PI_PHOENIX_BATCH | false | Enable batch exporting | | PI_PHOENIX_MAX_ATTR_BYTES | 16384 | Max bytes captured per span attribute |

Development

cd /home/phil/src/pi-phoenix
npm install
npm run typecheck

OpenRouter model sync via npx

If you use OpenRouter, you can sync OpenRouter model pricing into Phoenix for accurate cost tracking:

npx pi-phoenix-sync-openrouter --dry-run
npx pi-phoenix-sync-openrouter
PHOENIX_GRAPHQL=http://your-phoenix:6006/graphql npx pi-phoenix-sync-openrouter

Options:

• --dry-run: Print actions without mutating Phoenix
• --limit N: Process only the first N models

License

MIT