Symphony is an open-source coding agent orchestrator and harness developed by OpenAI. Built on Elixir and the Erlang VM (BEAM), Symphony provides the infrastructure required to manage, execute, and monitor autonomous coding agents in isolated development environments. In practical workflows, Symphony orchestrates coding agents across dedicated git worktrees and tasks. It handles task dispatching, skill execution, and lifecycle management while interfacing with issue trackers and code hosts such as GitHub and GitLab. The system manages tool execution and runbooks through structured repo-local skills and automated checks. Symphony distinguishes itself through its host-boundary security model and process isolation. It enforces strict credential separation, actively scrubbing host git and tracker authentication token aliases (such as GitHub and GitLab credentials) from agent execution runtimes to prevent autonomous agents from accidentally leaking or abusing host-level privileges. Symphony is open source, distributed via GitHub, and packaged as self-contained executables via Burrito alongside standard Elixir/Mix build pipelines.
Tags: agent harness, ai agent, cli, coding agent, developer tools, OpenSource