Knowledge Source Types and Limits
Knowledge sources live in a tenant-wide library at AI Agents > Knowledge Sources, and one source can be connected to any number of agents. This page lists the formats and limits for each type — for the workflows, see Knowledge Sources.
Each type has its own tab on the Knowledge Sources screen; FAQs is the tab label, and the entries inside a FAQ are Q&A pairs.
Source types
| Type | What it is | Formats and limits |
|---|---|---|
| FAQs | Named collections of question-and-answer (Q&A) pairs | Add pairs manually or auto-generate them from a file: csv, pdf, txt, html, md, xlsx, or docx; one file at a time; up to 100 MB. |
| Plain Text | A single named block of free-form text | Title up to 255 characters; text up to 50,000 characters per source. For longer content, upload the text as a file instead. |
| Websites | Links to public web pages | Public URLs only — pages must not require a login or block automated access. |
| Files | Uploaded documents | pdf, docx, txt, md, xlsx, csv, or html; up to 100 MB per file. |
| YouTube | Public YouTube videos or channels, transcribed automatically | Video duration is limited — the maximum depends on your deployment. Private, age-restricted, or region-locked videos fail. |
Limits at a glance
| Limit | Value |
|---|---|
| Plain Text title | 255 characters |
| Plain Text content | 50,000 characters per source |
| File size (Files and FAQ auto-generation) | 100 MB per file |
| Accepted file formats | csv, docx, html, md, pdf, txt, xlsx |
| FAQ auto-generation input | One file at a time |
| YouTube video length | Limited per video — the add dialog allows at most 3 hours, and your deployment may enforce a stricter limit during indexing |
Source statuses
Every source except individual Q&A pairs shows a Status in its table. Agents answer from a source only after it is indexed.
| Status | Meaning |
|---|---|
| Pending | Saved but not indexed yet. |
| Indexing | Flametree is processing the content. Stop indexing interrupts the run. |
| Ready | Indexed and available to connected agents. |
| Modified | Changed after the last indexing. Click Index to re-index. |
| Error | Indexing failed. Hover over the badge for the error message, then click Index to retry. |
note
You do not need to restart an agent after changing knowledge. Once a source is Ready, connected agents use the updated content.
Common limit errors
| Message or symptom | What to do |
|---|---|
| Text exceeds the 50,000 character limit. Upload as File instead. | Split the text into several Plain Text sources, or save it as a document and add it on the Files tab. |
| This video exceeds the 3-hour limit and cannot be added. | Pick a shorter video. Your deployment may also reject long videos during indexing (the source ends in Error) — if that happens, use a shorter one. |
| A file upload is rejected. | Check the type (pdf, docx, txt, md, xlsx, csv, html) and the size (under 100 MB). |
Related pages
- Knowledge Sources — create, index, and manage sources
- Simple mode — connect sources to an agent
- Knowledge Bases migration guide — move from the legacy Knowledge Base