Symphony

Symphony is a long-running service, not a chat tool. The specification (Draft v1, language-agnostic) defines an orchestrator that reads work from an issue tracker, keeps claim and retry state, creates an isolated workspace for each issue and runs one coding-agent session per issue. Ticket writes such as state changes, comments and PR links are normally done by the agent through tracker tools that Symphony executes with the configured credential.

The Elixir/OTP reference implementation launches Codex in app-server mode with a workflow prompt. Workspaces are directories under workspace.root, bootstrapped by a hooks.after_create script (the example runs git clone), so isolation is per-issue checkouts plus Codex's sandbox settings. If an issue reaches a terminal state, the agent is stopped and its workspaces are cleaned up.

State lives in the running orchestrator and in the tracker: blocked entries are kept in memory only and are cleared on restart, after which active issues can be dispatched again. Coordination between agents is indirect, through the tracker's states and comments.

The bundled workflow moves a ticket to Human Review when a PR is attached and validated, waits for a person, and only runs the land skill after the person moves it to Merging; Rework returns it to the agent. Codex approval defaults are strict: the Elixir implementation rejects sandbox approvals, rule approvals and MCP elicitations unless configured otherwise, and if Codex reports that input or approval is required the issue is shown as blocked in the dashboard and API. Moving an issue to a terminal state stops its agent.

git clone https://github.com/openai/symphony
cd symphony/elixir
mise trust
mise install
mise exec -- mix setup
mise exec -- mix build
mise exec -- ./bin/symphony ./WORKFLOW.md

# Prerequisites: mise (Elixir/Erlang), codex, git, and a tracker token
export LINEAR_API_KEY=...          # Linear personal API key
git clone https://github.com/openai/symphony
cd symphony/elixir
mise trust && mise install
mise exec -- mix setup && mise exec -- mix build

# WORKFLOW.md (copied into your repo) starts with YAML front matter like:
#   tracker: {kind: linear, provider: {project_slug: "..."}}
#   workspace: {root: ~/code/workspaces}
#   hooks: {after_create: "git clone git@github.com:your-org/your-repo.git ."}
#   agent: {max_concurrent_agents: 10, max_turns: 20}
#   codex: {command: codex app-server}
mise exec -- ./bin/symphony ./WORKFLOW.md --port 4000   # --port enables the dashboard

• Symphony Elixir is prototype software for evaluation; the README recommends implementing your own hardened version from SPEC.md, and the top-level README says trusted environments only.
• The bundled workflow depends on non-standard Linear statuses (Rework, Human Review, Merging) that you must create in Team Settings.
• The codex, git and tracker credentials must be present on the host, including with the Burrito executables.
• Workflows that run package managers need networkAccess: true in codex.turn_sandbox_policy, otherwise the Codex turn sandbox may deny DNS.
• If WORKFLOW.md is missing or has invalid YAML at startup, Symphony does not boot; a later invalid reload keeps the last good workflow.
• Blocked entries are in memory only, so a restart can make still-active issues dispatch candidates again.

No MCP client or server is documented for Symphony itself, so the record marks it unknown. The bundled workflow lets the agent use a Linear MCP server if one is configured, and MCP elicitation requests from Codex are treated as needing operator input.

The Elixir reference implementation starts Codex in app-server mode. The spec describes a generic coding-agent session, so other agents would need your own implementation.

The code is Apache-2.0 and no paid product is documented. Running it uses your own Codex and tracker accounts.

Not in the docs read. It creates a workspace directory per issue and the example hook runs git clone into it; the repository's .codex/worktree_init.sh only sets up the Elixir project for development.

OpenAI describes it as a low-key engineering preview for trusted environments, and the Elixir README recommends implementing your own hardened version from SPEC.md.