> For the complete documentation index, see [llms.txt](https://postica.gitbook.io/binding-system-3/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://postica.gitbook.io/binding-system-3/project-tools/diagnostics/path-value-preview.md).

# Path Value Preview

Check what is at the end of a path before you commit to it.

A path can be right and still point at the wrong thing. `bounds.size.magnitude` is a valid path; whether it is the number you meant is another question.

{% hint style="success" %}
**Learn by doing:** [A Health Bar with No Driver Class](/binding-system-3/tutorials/health-bar.md) uses the preview to check a path, and to write a test value back through it.
{% endhint %}

The preview shows the value at the end of the path, **at edit time**, without turning on full debugging. It is the one diagnostic that works before you press play, which makes it the right tool while you are still choosing what to bind to.

## Turning it on

The **preview toggle** on the bind row, tooltip *Preview data pointed by the path*. It is per binding.

<figure><img src="https://3048705056-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FLUfBXR02sJ5i0MxwYbaV%2Fuploads%2FcYOqd7YFmBW8XGlG0UQY%2FScreenshot%202026-09-28%20at%2017.38.19.png?alt=media&amp;token=b9616906-e1ec-45b2-b42a-95318732bf1c" alt="" width="563"><figcaption><p>The path value preview under a bind row</p></figcaption></figure>

## What it can preview

Serialized fields, and properties whose value can be resolved without running the game. Auto-properties with a serialized backing field usually work, because the backing field is what is actually read.

A path whose value cannot be resolved at edit time simply has no preview, and the toggle turns itself off rather than showing something misleading.

## Editable

The preview field is a real editor field. Typing into it writes the value back through the path, which is a fast way to check that a binding reacts the way you expect before you build the rest of the chain.

{% hint style="info" %}
Writing through the preview writes to the **source**, not to the binding. Undo works normally, and the change is a real change to the object.
{% endhint %}

## Preview versus Live Debug

<table><thead><tr><th width="230"></th><th>Path Value Preview</th><th>Live Debug</th></tr></thead><tbody><tr><td>Shows</td><td>One value, at the end of the path</td><td>Every stage of the pipeline</td></tr><tr><td>Cost</td><td>Low</td><td>Higher: every stage keeps its value</td></tr><tr><td>Editing it</td><td>Writes to the <strong>source</strong>, for real</td><td>Pins a value onto that stage of the <strong>debug chain</strong> only, and never touches the scene</td></tr><tr><td>Use while</td><td>Choosing a path</td><td>Diagnosing a wrong result</td></tr></tbody></table>

Both report at edit time as well as in play mode, and the two are independent, so you can have either or both. The one to reach for first is the preview: it answers "does this path give me what I think" without opening the stage rows.

## Turning previews off globally

The preview is a per-binding toggle, but if you never want it, the whole feature is part of what [Performance Mode](/binding-system-3/project-tools/performance/performance-mode.md) drops: it disables the live value preview along with the other decorative parts of the bind UI.