OpenAI Symphony

Skill by ara.so — Daily 2026 Skills collection.

Symphony turns project work into isolated, autonomous implementation runs, allowing teams to manage work instead of supervising coding agents. Instead of watching an agent code, you define tasks (e.g. in Linear), and Symphony spawns agents that complete them, provide proof of work (CI status, PR reviews, walkthrough videos), and land PRs autonomously.

What Symphony Does

• Monitors a work tracker (e.g. Linear) for tasks
• Spawns isolated agent runs per task (using Codex or similar)
• Each agent implements the task, opens a PR, and provides proof of work
• Engineers review outcomes, not agent sessions
• Works best in codebases using harness engineering

Installation Options

Option 1: Ask an agent to build it

Paste this prompt into Claude Code, Cursor, or Codex:

Implement Symphony according to the following spec:
https://github.com/openai/symphony/blob/main/SPEC.md

Option 2: Use the Elixir reference implementation

git clone https://github.com/openai/symphony.git
cd symphony/elixir

Follow elixir/README.md, or ask an agent:

Set up Symphony for my repository based on
https://github.com/openai/symphony/blob/main/elixir/README.md

Elixir Reference Implementation Setup

Requirements

• Elixir + Mix installed
• An OpenAI API key (for Codex agent)
• A Linear API key (if using Linear integration)
• A GitHub token (for PR operations)

Environment Variables

export OPENAI_API_KEY="sk-..."           # OpenAI API key for Codex
export LINEAR_API_KEY="lin_api_..."      # Linear integration
export GITHUB_TOKEN="ghp_..."           # GitHub PR operations
export SYMPHONY_REPO_PATH="/path/to/repo"  # Target repository

Install Dependencies

cd elixir
mix deps.get

Configuration (elixir/config/config.exs)

import Config

config :symphony,
  openai_api_key: System.get_env("OPENAI_API_KEY"),
  linear_api_key: System.get_env("LINEAR_API_KEY"),
  github_token: System.get_env("GITHUB_TOKEN"),
  repo_path: System.get_env("SYMPHONY_REPO_PATH", "./"),
  poll_interval_ms: 30_000,
  max_concurrent_agents: 3

Run Symphony

mix symphony.start
# or in IEx for development
iex -S mix

Core Concepts

Isolated Implementation Runs

Each task gets its own isolated run:

• Fresh git branch per task
• Agent operates only within that branch
• No shared state between runs
• Proof of work collected before PR merge

Proof of Work

Before a PR is accepted, Symphony collects:

• CI/CD pipeline status
• PR review feedback
• Complexity analysis
• (optionally) walkthrough videos

Key Elixir Modules & Patterns

Starting the Symphony supervisor

# In your application.ex or directly
defmodule MyApp.Application do
  use Application

  def start(_type, _args) do
    children = [
      Symphony.Supervisor
    ]
    Supervisor.start_link(children, strategy: :one_for_one)
  end
end

Defining a Task (Symphony Task struct)

defmodule Symphony.Task do
  @type t :: %__MODULE__{
    id: String.t(),
    title: String.t(),
    description: String.t(),
    source: :linear | :manual,
    status: :pending | :running | :completed | :failed,
    branch: String.t() | nil,
    pr_url: String.t() | nil,
    proof_of_work: map() | nil
  }

  defstruct [:id, :title, :description, :source,
             status: :pending, branch: nil,
             pr_url: nil, proof_of_work: nil]
end

Spawning an Agent Run

defmodule Symphony.AgentRunner do
  @doc """
  Spawns an isolated agent run for a given task.
  Each run gets its own branch and Codex session.
  """
  def run(task) do
    branch = "symphony/#{task.id}-#{slugify(task.title)}"

    with :ok <- Git.create_branch(branch),
         {:ok, result} <- Codex.implement(task, branch),
         {:ok, pr_url} <- GitHub.open_pr(branch, task),
         {:ok, proof} <- ProofOfWork.collect(pr_url) do
      {:ok, %{task | status: :completed, pr_url: pr_url, proof_of_work: proof}}
    else
      {:error, reason} -> {:error, reason}
    end
  end

  defp slugify(title) do
    title
    |> String.downcase()
    |> String.replace(~r/[^a-z0-9]+/, "-")
    |> String.trim("-")
  end
end

Linear Integration — Polling for Tasks

defmodule Symphony.Linear.Poller do
  use GenServer

  @poll_interval Application.compile_env(:symphony, :poll_interval_ms, 30_000)

  def start_link(opts \\ []) do
    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
  end

  def init(_opts) do
    schedule_poll()
    {:ok, %{processed_ids: MapSet.new()}}
  end

  def handle_info(:poll, state) do
    case Symphony.Linear.