The **Compare** button sits at the right edge of the editor tab bar, next to the **Editor** and **Commit History** tabs. Its outlined style indicates comparison mode is off; clicking it switches the button to a filled style and collapses the file tree.
When you enter comparison mode:
* The file tree collapses to give variants maximum horizontal space
* The navigation sidebar minimizes to icons
* Two variant panels appear side-by-side, ready for configuration
Click **Compare** again to exit and return to the standard editor. AgentMark preserves your variant configurations, so re-entering comparison mode restores them.
## Configuring variants
Each variant panel has its own independent configuration:
Two variant panels fill the editor area side-by-side. Each panel header shows a **Variant 1** / **Variant 2** label, an **Apply** button, duplicate and remove icons, a **Model** dropdown, a **Temperature** slider with a settings-gear button, and a **Run** button.
### Model selection
Select a different model for each variant from the **Model** dropdown. All models configured in your [model schema](/configure/model-schemas) are available.
### Temperature
The **Temperature** slider is inline for quick adjustments. Click the **gear icon** to open the **Model Settings** dialog for max tokens, top-p, and other settings.
### Prompt override
Click the **Prompt** accordion on any variant to expand the prompt editor. Each variant starts with the base prompt text, and you can edit it independently.
The screenshot shows the **Prompt** accordion expanded on the left variant, revealing the code editor populated with the base prompt text. Edits here only affect this variant.
When a variant's prompt differs from the base, a **Modified** badge appears. This makes it easy to see which variants have custom prompt text at a glance.
## Running variants
### Run all
Click **Run All** in the toolbar to execute all variants simultaneously. Each variant streams its output independently, so if one errors, the others continue.
### Run single
Each variant has its own **Run** button for re-running just that variant without affecting others.
### Output and metadata
After execution, each variant displays its output alongside metadata chips showing:
* **Model name**: which model generated the response
* **Latency**: end-to-end response time
* **Token usage**: prompt / completion / total tokens
* **Finish reason**: why the model stopped (for example, `stop`, `length`)
After **Run All** completes, each variant shows its streamed output as monospaced text, followed by a bottom metadata bar of chips: model name, latency (for example `3.45s`), a combined prompt / completion / total tokens chip, and the finish reason.
## Managing variants
### Add and remove
Click **Add Variant** to add panels (up to 6 maximum). Remove a variant with the **X** button in its header (minimum 2 required).
### Duplicate
Click the **copy icon** on any variant to duplicate its model, parameters, and prompt override into a new panel.
### Grid layout
AgentMark arranges variants in a 3-column grid:
* **2-3 variants**: single row
* **4-6 variants**: wraps to two rows (3 per row)
Six variants fill a 3×2 grid, three variants per row. The **Run All** button in the toolbar header executes every variant in parallel.
## Applying a variant
Once you've found the best configuration, click the **Apply** button on that variant's header. This writes the variant's model, parameters, and prompt text back to the main editor, then exits comparison mode so you can review and publish.
## Limitations
* **Maximum 6 variants** at a time
* **All variants share variables**
* **No dataset integration**: for systematic evaluation across many inputs, use [Experiments](/evaluate/running-experiments)
* **Ephemeral state**: variant configurations aren't persisted across page reloads
## What's next
* [Create a prompt](/build/creating-prompts): set up your base prompt before comparing
* [Version control](/build/version-control): publish the winning variant as a new version
* [Experiments](/evaluate/running-experiments): run prompts against datasets for systematic evaluation
Reach out any time: