The Bland AI knowledge base: how it works, and how to load your knowledge base into it

On Bland AI, a knowledge source is something the agent may choose to search. You add a source (a file, a website, a block of text or a synced document) to your organisation, attach it to an agent, and during the call the agent decides whether to search it, based on the source's name and description. A vague description means a source that rarely gets searched.

This page is written from Bland AI's own documentation, checked on 25 September 2026. KB Builder is not affiliated with Bland AI. Our own live calls so far ran on a different platform, so the advice below applies what we learned there; it has not been tested on Bland calls yet.

How the Bland AI knowledge base works

	What the docs say
Where it lives	Knowledge in the dashboard. Sources belong to the organisation and are attached to agents
How the agent uses it	The agent decides whether to search a source, from its name and description
What you can add	Files (PDF, TXT, CSV, JSON, DOCX, up to 10 MB each), websites by sitemap or URL list, typed text up to one million characters, Notion or Google Docs
Markdown	Not listed as an upload type; paste it as Text or upload as .txt
Knowledge bases per plan	Start 10, Build 50, Enterprise unlimited
Chunk size, chunks per search	Not stated in the docs
Updating	Edit in place (each save is a version and is re-embedded), or replace a file with one of the same type
Extra charge	None stated

Bland's Source testing tab shows the search query it generated, whether the source could answer, and the chunks retrieved with their scores. Use it before going live.

Where it goes wrong on calls

The source isn't searched. If the description says "Company info" and the caller asks "How much is a root canal?", the agent may not think the source is relevant. Bland's docs say to describe the source "in the words a caller would use".

The wrong passage wins. Bland's own diagnosis: "A good score on the wrong passage means the source covers two things at once." When one piece of text mentions two products and their prices, the search can't tell them apart, and neither can the agent.

Changes don't reach live calls. Edits on a published environment don't save, and changes reach callers only after you publish and promote the agent.

How to load a KB Builder file into Bland AI

A KB Builder knowledge base is a Markdown file written in short sections that each name one product or service, so a retrieved passage never covers two things at once.

1. Go to Knowledge → Sources → Add sources and choose Text.
2. Name it after the business, and write a description in callers' words, for example: "Prices, timings, what's included, policies, location and contact details for every product and service of [business]." You can't edit the description later.
3. Paste the whole file and save. Wait until the status leaves Processing.
4. Switch to the agent, check the top bar says Development, open Knowledge, tick the source and save.
5. Publish and promote the agent, then check a few caller questions in Source testing.

When the business's website changes, rebuild the file in KB Builder and edit the source in place: paste the new text over the old and save. Bland keeps the old version and re-indexes the new one.

Lines to add to the agent's prompt

The first line makes sure the source is searched; the rest come from our own live calls:

Before answering any question about the business's products, services, prices, timings, policies or contact details, search the business's knowledge source.
Answer questions about the business only from the knowledge base. If it doesn't have the answer, say you will check, and give the business's phone number.
Give a price, time or rule only from a sentence that names the product or service the caller asked about.
Whenever you give a price, say the name of the product or service with it.
If the caller hasn't said which product or service they mean, ask before answering.
When the knowledge base says something has not been confirmed, say exactly that. Never guess.
Don't promise messages, callbacks or bookings unless the knowledge base says the business offers them.

A note for API users

Over the API, a source is created with POST /v1/knowledge/learn and attached to a call through its KB-... id in tools. The API's update endpoint changes only the name and description, not the content, so new content means a new source.