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

# How Do Agents Use Brain?

Attach knowledge sources to an agent under **Knowledge Sources** in its configuration. Click **Add** to attach an existing source from your Personal, Team, or Organization Brain — or create a new one, including a plain file upload. The agent then searches those sources when answering.

Two things to know about what the agent can pull from:

* **Attaching is a sharing decision.** Everyone who uses the agent gets answers from its attached sources, even people who could not open those sources in Brain themselves. The exception is sources with Document access set to **Original source**: those still check each reader's own document permissions, so different users can get different answers from the same agent.
* **You can narrow each attachment.** An attached source is either **All files** or **Custom** — use Custom to uncheck folders or files the agent should not search, without changing the source itself or other agents using it.

Personal Brain sources attached to an agent work only in your own chats with it. To give the whole team the same knowledge, attach a team or organization source instead.

To detach a source, use **Remove** on its row in the agent's configuration. Deleting a source from Brain detaches it from every agent.

## FAQ

<AccordionGroup>
  <Accordion title="The agent cannot find something that is in the source">
    Check three things: the source has finished syncing (not a draft or failed), the attachment's Custom selection includes the folder the content lives in, and — for Original source mode — that the document is shared with your Gumloop login email. See [Why is a document missing?](/help/brain/why-is-a-document-missing)
  </Accordion>

  <Accordion title="Do agent answers from Brain cost credits?">
    Yes — Brain searches are part of the agent's normal per-run credit usage.
  </Accordion>

  <Accordion title="Does someone using the agent need their own connector?">
    No. Reading Brain never uses the reader's connectors. See [Do I need a connector to read Brain?](/help/brain/do-i-need-a-connector-to-read-brain)
  </Accordion>

  <Accordion title="A teammate says the agent finds nothing from Brain at all">
    Their role may restrict Brain access — organization admins can deny it through custom roles. Ask an admin to check.
  </Accordion>
</AccordionGroup>

## Related

<CardGroup cols={2}>
  <Card title="Do I need a connector to read Brain?" icon="plug" href="/help/brain/do-i-need-a-connector-to-read-brain">
    Connectors vs knowledge sources
  </Card>

  <Card title="Personal vs Team vs Organization Brain" icon="layer-group" href="/help/brain/personal-team-org-brain">
    Which scope to attach from
  </Card>
</CardGroup>