> ## Documentation Index
> Fetch the complete documentation index at: https://docs.biomni.phylo.bio/llms.txt
> Use this file to discover all available pages before exploring further.

# Chemical Structures

> Preview, draw, and edit small molecules

Biomni draws 2D structures for molecule files and lets you draw molecules to
send to a task or add to a result file.

## Preview molecule files

Open a supported file to see its structures:

* **SDF** files open as a **2D table**, a **2D grid**, or a **3D structure**.
* **CSV**, **TSV**, and **SMI** files draw SMILES columns in place. Biomni
  detects structure columns, and you can choose which columns are drawn.

Large libraries are split into pages.

## Draw a molecule for a message

1. Select **+ Add** in the composer.
2. Choose **Draw molecule**.
3. Draw the structure and select **Add**.

The drawing is saved as a SMILES (`.smi`) file in the project's
`drawn-molecules-input` folder and attached to your message. Add one molecule
at a time.

## Edit molecules in a result file

SDF, CSV, TSV, and SMI files generated by a task can be edited from their
preview:

* **Add molecule** appends a new structure to the end of the file. Only the
  structure is added; other columns stay empty.
* **Edit molecule** (the pencil on a structure in the table, or the tile menu
  in the grid) opens the structure in the editor:
  * **Save changes** replaces the structure. Other values in that row are left
    out unless you tick them under **Keep values**, because they may not
    describe the new structure.
  * **Add as new molecule** appends the edited structure and leaves the
    original unchanged.
* **Delete** in the row or tile menu removes that molecule.

Saving changes and deleting both show an **Undo** option.

> [!NOTE]
>
> Editing is available for task result files up to 25 MB, once the agent has
> finished. A file must keep at least one molecule. Files in shared replays and
> project files outside a task's results can be previewed but not edited.
> Drawing and editing molecules may not be enabled in every workspace.

For other file actions, see [Projects & Drive](https://docs.biomni.phylo.bio/features/projects-and-drive.md).


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