OpenGraph previews

marimo can attach OpenGraph metadata to notebooks for:

• previews in the marimo run <directory> gallery
• link previews (OpenGraph tags in the notebook HTML)

You configure this metadata in your notebook file using inline script metadata (PEP 723), under [tool.marimo.opengraph].

Configure metadata

Add an [tool.marimo.opengraph] section to your script metadata:

# /// script
# [tool.marimo.opengraph]
# title = "My notebook"
# description = "An interactive marimo app."
# ///

Available fields:

• title: Title used in previews (defaults to a title-cased filename).
• description: Short description shown in previews.
• image: Optional thumbnail image. Must be either:
  • an HTTPS URL, or
  • a notebook-relative path under __marimo__/ (for example, __marimo__/assets/my_notebook/opengraph.png).

If you generate thumbnails to the default location (see below), you typically do not need to set image: marimo will automatically use __marimo__/assets/<notebook_stem>/opengraph.png when it exists.

!!! note "Relative image paths"

For security, marimo only serves notebook-relative `image` paths from the notebook's `__marimo__/` directory.

Thumbnails

If you do not provide an image, marimo can still serve a deterministic placeholder thumbnail. If a screenshot-based thumbnail exists at the default location, marimo will automatically use it.

The default thumbnail location is:

__marimo__/assets/<notebook_stem>/opengraph.png

To generate these thumbnails, use:

marimo export thumbnail notebook.py
marimo export thumbnail folder/

For execution and sandbox options (and for Playwright installation instructions), see Thumbnails.

Dynamic metadata

For dynamic previews, you can provide a generator function in script metadata. Generators must be top-level functions (decorated with @app.function) and cannot depend on values defined in regular cells, so that they can be safely executed in the marimo CLI without running the whole notebook.

In script metadata, point generator at the name of a function defined in the notebook:

# /// script
# [tool.marimo.opengraph]
# description = "This description is static."
# generator = "generate_opengraph"
# ///

Then define the generator in a notebook cell:

/// marimo-embed

@app.function
def generate_opengraph(context, parent):
    import datetime as dt
    from pathlib import Path
    from urllib.parse import quote_plus

    # Merge behavior: we return `title` and `image`, so the static `description` stays intact (it's already in `parent`).
    stem = Path(context.filepath).stem
    label = quote_plus(f"{stem} {dt.datetime.now().isoformat()}")
    title = f"{parent.title} (Dynamic)" if parent.title else "Dynamic OpenGraph"
    return {
        "title": title,
        "image": f"https://placehold.co/1200x630/png?text={label}",
    }

///

The generator return value is merged on top of the resolved "parent" metadata (declared fields + defaults). Any fields not returned by the generator are inherited from parent.

Generator signatures

The generator may accept 0, 1, or 2 positional arguments:

• generate_opengraph()
• generate_opengraph(context)
• generate_opengraph(context, parent)

Type hints:

• context: marimo._metadata.opengraph.OpenGraphContext
• parent: marimo._metadata.opengraph.OpenGraphMetadata

context is an object with useful runtime information:

• context.filepath: absolute path to the notebook
• context.file_key: file router key (often a workspace-relative path)
• context.base_url: server base URL (when running with marimo run)
• context.mode: "run" or "edit"

The generator may return:

• an OpenGraphMetadata instance
• a dict with any of title, description, and image
• None (to leave the parent metadata unchanged)