OpenAI's Symphony: Autonomous Codex Agents for Linear Issues

Better Stack2026-05-09go watch the original →

the gist

Symphony orchestrates Codex CLI agents to poll Linear issues, claim 'to-do' tasks, spin up isolated workspaces, execute via workflow prompts, and create PRs using repo hooks—install by prompting an agent with a 2000+ line spec or cloning the Elixir repo.

The Breakthrough

OpenAI open-sourced Symphony to eliminate human supervision bottlenecks by enabling Codex agents to autonomously claim Linear issues in 'to-do' status, create isolated workspaces matching issue IDs, execute tasks via Codex CLI, update issue status to 'done', and flag humans only for reviews.

What Actually Worked

Symphony polls Linear for issues using a personal API key stored in workflow.yaml frontmatter, which specifies active_states (e.g., 'to-do'), workspace_root, and codex_command (shell command to launch the agent).
Each claimed issue triggers a workspace directory with the issue ID (e.g., SYN-7); Codex CLI receives a markdown prompt from workflow.yaml to build the app, such as a Hello World TypeScript+Bun app.
Users add create_after hook to clone a repo into the workspace and checkout a new branch; run_after hook stages files, commits changes, pushes the branch, and creates a pull request linked to the Linear ticket.
Primary install prompts a coding agent (e.g., GPT-4o, Claude SDK) with a 2000+ line spec file from the repo to build Symphony in any language (e.g., Python version via Codex); alternative clones the Elixir repo, builds, and runs via workflow.
Run Symphony with UV tool; it integrates existing Codex skills, MCP tools, and plugins.

Context

OpenAI engineers faced a bottleneck supervising only 3-5 concurrent Codex sessions due to context switching. Symphony scales this by automating agent dispatch via issue trackers like Linear, allowing a central agent harness for team-wide tasks with visibility into others' prompts and features. The video demos basic setup on a Hello World app and repo README update, notes customizability via agent-built versions fosters ownership, and positions Symphony as barebones compared to easier-setup MultiAI or feature-rich Conductor.

Notable Quotes

"Symphony has the weirdest installation process I've ever seen in my life or it could be the most genius way to install something."
"If you built your own version of Symphony you would feel responsible for it you'd fix the bugs you'd add the features and you'd essentially maintain it."

Content References

Announcement article details Symphony's design for Codex orchestration. GitHub repo provides the spec file, workflow.yaml example, and Elixir source.