Code Studio

Code Studio is a local example app built with the Temporal Agent Harness. It demonstrates how to build an editable, multi-agent software development workflow with human approvals, shared editing, and durable execution.

The example defines six agents: Ideation, Planner, Design, Development, Review, and Deployment. You can customize their instructions and tools, run them on a feature, inspect their work, and approve the next step. The application defines the process; the harness provides durable agent execution underneath it.

This is an example for learning and experimentation, not a production development platform. It runs on one computer and has no user authentication. Display names identify browser participants; they are not accounts. Keep the services on loopback and use codebases and test commands you trust.

What it demonstrates

• Editable agent instructions, settings, and Python orchestration.
• Shared editing and conversations across browser sessions.
• A coordinator that delegates to stage agents, with human approval gates and a bounded review/repair loop.
• Saved inputs, handoffs, tool activity, check results, and restart recovery.
• Isolated feature workspaces, local release ZIPs, and reviewed merges into a project.
• Paired experiments for comparing agent playbooks against the same starting inputs.

Run locally

Requirements:

• macOS or Linux: the local host uses Unix process and file-lock APIs.
• Git, Python 3.11+, and uv.
• Node.js 22.23.4+ and npm, matching package.json.
• Temporal CLI and, optionally, just.
• An OpenAI API key with access to the configured models. The example currently defaults to gpt-6-luna and also supports gpt-6.1-sol in agent settings.

The runtime uses temporal-agent-harness[ui,openai-agents,code-mode]==0.6.0 and @temporalio/agent-harness-svelte@0.1.0. Dependencies come from PyPI and npm; no sibling harness checkout is required.

From the repository root:

# Create the local configuration only if it does not already exist.
if [ ! -f .env.local ]; then cp .env.example .env.local; fi
# Edit .env.local and set OPENAI_API_KEY before continuing.
just install
just dev

Without just:

uv sync
npm ci
uv run --env-file .env.local python scripts/dev.py

Use the same .env.local setup with either approach. Model calls use your API key and incur usage charges. Source, prompts, and tool results are sent to the configured model. Common credential files are excluded from source copies, but secrets embedded in ordinary source files may still be included.

Open http://127.0.0.1:5174. The launcher starts the local services, creates the code-studio namespace if needed, and reuses an existing Temporal server on port 7233. Ctrl-C stops the processes it started. Restart just dev after Python changes.

Service	Address
Code Studio	http://127.0.0.1:5174
Harness UI/API	http://127.0.0.1:8001
Workspace host	http://127.0.0.1:8002
Temporal server	localhost:7233
Temporal UI	http://localhost:8233/namespaces/code-studio/workflows

Local state and logs live under .local/. Keep the workspace data and Temporal state together when restarting a demo; they contain the saved runs and conversations.

Try a feature

1. Open Features and choose Start a feature. Use this checkout or a disposable project as the working directory. Current working files includes uncommitted source changes in an isolated copy; Committed Git revision starts a Git worktree.
2. Describe a small change, review the proposed brief and acceptance criteria, and start the feature. For collaboration, open another browser session with a different display name.
3. Follow Ideation and Planner, then choose Approve plan & continue. Design, Development, and Review work through the feature and its checks.
4. Inspect the code diff, handoffs, and check evidence. Review may send changes back to Development. Approve the review when you are ready to continue.
5. Deployment prepares a local source ZIP and deployment notes. It does not publish, push, or deploy the project to a remote service.
6. For a feature created from current working files, use Merge into project to review and apply the changes locally. The app retains recovery information and offers Undo merge. Git-worktree features use an explicit Git branch review/merge.

Open an agent from Agents, or choose Customize agent within a feature, to edit its definition. Changes apply to future stage runs; existing runs keep their saved inputs.

Agent file	Purpose
<stage>_agent.py	Python orchestration executed through Code Mode.
<stage>_instructions.md	The agent's role, priorities, and instructions.
<stage>_settings.json	Model, enabled tools, and turn limit.

The usage guide covers stage questions, approvals, conflict recovery, playbook experiments, and the standalone PR-review and DAG examples. The demo walkthrough provides a guided presentation.

Optional previews and editing-only mode

For read-only browser previews, install Chromium on the host:

uv run playwright install chromium

Then use a feature's Browser preview tab. The current adapter previews Code Studio's Vite frontend against the running backend. It does not run changed backend code or verify saving and other mutations.

To try shared editing without Temporal or a model key, run these in separate terminals after installing dependencies and creating .env.local:

just collaboration

just studio

Agent execution is disabled in this mode. Stop both processes before using just dev.

Explore the code

Location	Purpose
cooperative/definitions.py and cooperative/prompts.py	Stage definitions and default playbooks.
agent_dag/pipeline_agent.py and agent_dag/live_stage.py	Coordinator and stage workflows.
cooperative/	Approvals, shared artifacts, experiments, checks, and local integration.
workspace/	Shared editing, persistence, and agent callback execution.
features/	Feature source copies, Git worktrees, and file operations.
sdlc/	Standalone PR-review example and GitHub evidence capture.
ui/	Svelte application.

Checks

# Selected application checks without a running Temporal server or model credentials.
just check-agents

# Full build and test suite.
just check

The full suite requires the Temporal CLI, Chromium, and permission to bind local ports. Temporal integration tests start an ephemeral server and use scripted agents or model stand-ins. These tests do not replace a live-model smoke test. npm run test:collaboration tests editor and client logic; it is not rendered browser automation.

License and attribution

Code Studio is available under the MIT license.