> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tryblend.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Handles, edges & connections
> The dots you wire together, the connections they form, and the rules that govern what's allowed.
**Handles** are the small dots on a node's edges. They come in two kinds:
* **Input handles** sit on the **left** of a node. They receive data.
* **Output handles** sit on the **right** of a node. They emit data.
An **edge** is a connection. You draw one by dragging from an output handle to a compatible input handle. Data flows along that edge from the source node's output into the target node's input.
## Connection rules
A few rules govern what you're allowed to wire together:
| Rule | Behavior |
| ------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Single vs. multiple inputs** | Most input handles accept exactly one edge. Some — like an Agent's **Tools** input or a [Choose Output](/workflow/nodes/output-comparison)'s **Choices** input — accept many. |
| **No cycles** | An edge that would loop data back into one of its own upstream nodes is rejected. |
| **No self-connections** | A node can't connect to itself. |
| **Type compatibility** | The output type and input type must be compatible. See [Data types](/concepts/data-types). |
If a connection is rejected, the editor tells you why — usually a type mismatch, a cycle, or an input handle that's already full.
## Related
What each handle carries, and which source types connect to which targets.
When a handle carries one value versus a whole list.