# Agent Workbench by Celest

## Make it yours.

Open a Microsoft 365 Copilot agent package, see what it contains, refine the instructions that matter, and review your changes before exporting the next version.

Canonical URL: https://celest.dev/agent-workbench

Sign up for your [Celest account](https://celest.dev/agent-workbench/start) and its setup path. This is separate from adding an agent to Microsoft 365. The [Microsoft 365 preview guide](https://celest.dev/agent-workbench/docs) explains host-specific context and invited access for Microsoft 365 Copilot, Copilot Cowork, or both.

The public page keeps an **Add to Microsoft 365** action visible but disabled while its Marketplace listing destination is pending review; no Marketplace URL is linked yet.

[Watch Make It Yours on YouTube](https://www.youtube.com/watch?v=eW9OPzTwiq0) — 01:04.

## Give your agent a clearer job.

Agent Workbench combines tools for building, evaluating, and repairing Microsoft 365 Copilot agents. This workflow starts with an app package: its agent definition, instructions, icons, and supporting files.

1. **Open:** See your agent's instructions, settings, and files together in Agent Canvas.
2. **Refine:** Change an instruction in place, then compare the source text with its readable preview.
3. **Review:** Run the package check and read what it flags before you export.
4. **Export:** Export the updated package. Your original stays available.

## Inside the workbench

These are actual Agent Workbench screens. Weekly Brief is a fictional example.

- [Agent overview](https://celest.dev/agent-workbench-assets/launch/01-agent-overview.png): instructions and package details.
- [Instruction editor](https://celest.dev/agent-workbench-assets/launch/02-instructions-edit.png): edit one instruction and check the rendered preview. The highlighted source change makes accountability explicit when a note names an owner or target date.
- [Review and export](https://celest.dev/agent-workbench-assets/launch/03-review-export.png): run the local check, then export the corrected package. The read-only check inspects structure, references, and supported fields without changing files; the latest local Doctor run is ready for Microsoft validation with zero remaining findings.

## Work in the tools you already use.

- **Microsoft 365 Copilot:** Inspect and improve your agent alongside the Copilot conversation. [Copilot guide](https://celest.dev/agent-workbench/docs#copilot).
- **Copilot Cowork:** Attach a package ZIP to a Cowork task to inspect, revise, and repair its files. [Cowork guide](https://celest.dev/agent-workbench/docs#cowork).

Review your changes before using the next version. Keep the original package available. Package checks help you prepare; test the updated agent in the Microsoft service where you will use it.

[Sign up](https://celest.dev/agent-workbench/start) · [Microsoft 365 preview guide](https://celest.dev/agent-workbench/docs) · [Support](https://celest.dev/agent-workbench/support)