Knowledge
The Knowledge block gives a workflow direct access to a knowledgebase -- search it with vector/hybrid search, or add content to it, without leaving the canvas.

Operations
Searches the selected knowledgebase. Search Query is optional if you're filtering purely by tags. Number of Results defaults to 10. Tag Filters narrows the search to documents matching specific tag values before the vector/hybrid search runs -- see Tags and Filtering for the full set of operators available per tag type.
Adds a single chunk directly to an existing document in the knowledgebase, bypassing the normal upload-and-chunk pipeline.
Creates a new document in the knowledgebase from content the workflow generates, rather than an uploaded file.
Clarify which tags actually exist in the target knowledgebase before relying on Tag Filters in a workflow -- there's no validation that a tag name you type in actually matches anything.
Full Reference
Every operation, parameter, and output shape is documented in full at Knowledge (tools).