Running Symphony with Upstash Box in Minutes

Did you guess a developer?

The correct answer is Symphony, and today we're showing you how to run it on Upstash Box.

What is Symphony?

Symphony is an open-source orchestrator that connects your Linear project to OpenAI's Codex. It polls your tickets, picks up ones in the Todo state, and runs a Codex agent inside a Git repository to implement them end-to-end.

The agent creates a branch, writes the code, runs tests, opens a PR, and moves the ticket through your workflow from In Progress to Human Review. If a reviewer requests changes, it goes to Rework and the agent tries again. When the PR is approved, it lands the merge automatically.

Why Upstash Box?

Symphony needs a place to live. It's a long-running process that keeps the Linear connection open, maintains a workspace directory per ticket, and builds Elixir from source. That's not a serverless function. It's a computer.

This is exactly what Upstash Box was built for. Box gives you a persistent cloud computer that:

• Keeps its filesystem — the Elixir build, the cloned repo, everything stays between runs
• Charges on core CPU usage — no CPU charges when Symphony is waiting for a ticket
• Single source of Management — all the symphony processes can live in seperate boxes
• Advanced Monitoring — the sdk and the console gives you the tools you need to operate and debug

Setting it up

We built a CLI that handles everything in one command:

npx symphony-box

It prompts you to provide four credentials:

• Upstash Box API key — to create and control the Box
• OpenAI API key — used by Codex to write the code
• Linear API key — to poll and update your tickets
• GitHub token — to push branches and open PRs

Then you pick a GitHub repo and a Linear project from your account. Finally, it asks whether you want to keep the box alive for production.

┌ Symphony Box Setup
◇ Upstash Box API key: ****
◇ OpenAI API key: ****
◇ Linear API key: ****
◇ GitHub token (requires read/write for contents and pull requests): ****
◇ Select a GitHub repo: upstash/my-repo
◇ Select a Linear project: Backend
◇ Keep the box alive for production? (recommended — box stays running even when idle; otherwise it freezes after inactivity) yes
⠹ Cloning and building Symphony (~5 mins)...
✓ Done
 
Symphony is running!
 
  Box ID: sparkling-fox-12345

Behind the scenes, the CLI:

1. Checks your Linear project for required workflow states (Rework, Human Review, Merging) and offers to create any that are missing
2. Creates an Upstash Box with your API keys injected as environment variables
3. Installs system dependencies and Codex on the box
4. Clones your repo and writes a WORKFLOW.md config that tells Symphony how to handle your tickets
5. Builds Symphony from source and starts it
6. If you chose keep-alive, registers Symphony as the box's init command so it restarts automatically if the box ever reboots

After setup, Symphony streams its output to your terminal. When you close the terminal, Symphony keeps running on the box.

Keep-alive vs default

The workflow

Once running, Symphony expects tickets to move through these Linear states:

The WORKFLOW.md file controls how the agent behaves inside each ticket. It's a markdown file with YAML frontmatter that configures the Linear connection, the Codex settings, and the agent instructions. The CLI generates it automatically from your project's Linear slug and repo URL.

Try it

npx symphony-box

The source is on GitHub. Symphony itself is open source at openai/symphony.

We'd love to hear how it works for your repo..