Knowledge Base - telli API Documentation

The knowledge base gives your telli agent access to your own documents so it can answer questions using your specific information during calls. Instead of relying only on its system prompt, the agent can search through your uploaded files in real time to find accurate answers. Think of it as giving your agent a reference manual it can flip through mid-conversation. When a caller asks something that’s covered in your documents, the agent will look it up and respond with the right information.

Quick Start

Create a Knowledge Base

Go to Knowledge Base in the sidebar navigation and click Create

Upload your files

Give your knowledge base a name and upload up to 5 files (PDF, Word, TXT, or Markdown)

Wait for processing

Your knowledge base will process your documents (usually takes less than a few minutes)

Attach to your agent

Go to Agent Settings → Knowledge Base section, select your knowledge base, and save

What Can You Use It For?
Supported File Types & Limits
How It Works During a Call

FAQs & company info — Upload your frequently asked questions so the agent handles common inquiries accurately
Product details & pricing — Give the agent access to your catalog so it can answer specific product questions
Policies & procedures — Upload return policies, terms of service, or internal procedures
Service descriptions — Detailed descriptions of your services that are too long for the system prompt
Any reference material — Anything you’d want a human employee to have on their desk while taking calls

Example: You upload your company’s FAQ document, product catalog, or pricing sheet. When a caller asks “What are your opening hours?” or “How much does the premium plan cost?”, your agent searches the knowledge base and gives the correct answer — straight from your own documents.

Format	Extension
PDF	`.pdf`
Word	`.docx`
Plain Text	`.txt`
Markdown	`.md`

	Limit
Files per knowledge base	Up to 5
File size	Up to 20 MB per file
Total content	Approximately 1,500 pages across all files
Knowledge bases per agent	1

A caller asks a question that the agent thinks might be answered in the knowledge base
The agent automatically decides to search the knowledge base — you can also call [searchKnowledgeBase] to make it clearer for the agent when to use the knowledge base
While searching, the agent briefly lets the caller know it’s looking up the information (e.g., “Let me check that for you”)
The agent finds relevant information and responds with an answer based on your documents
The search happens in real time and typically takes just a couple of seconds

The agent uses two search methods behind the scenes — semantic search (understanding the meaning of the question) and keyword search (matching specific terms) — to find the most relevant information from your documents.

Best Practices
Good to Know

Keep Documents FocusedA document about one topic works better than a massive document covering everything.

Use Clear HeadingsEspecially in .md and .docx files, headings help telli break up the content into searchable sections.

Be ExplicitWrite your documents the way you’d want someone to answer the phone. If the answer to “What are your hours?” is in your document, make sure it clearly says something like “Our opening hours are Monday–Friday, 9am–5pm”.

Update When Things ChangeIf your pricing, policies, or hours change, update the files in your knowledge base so the agent always has current information.

Use the Right FormatPDFs work great for existing documents; Markdown or plain text is ideal if you’re writing content specifically for the agent.

The knowledge base is processed once when you create or update it — it doesn’t re-process on every call, so there’s no ongoing delay
The agent decides on its own when to search the knowledge base — you don’t need to configure specific trigger phrases
If the agent can’t find relevant information in the knowledge base, it will fall back to its general knowledge and system prompt
Processing status is shown on the knowledge base card — you’ll see a spinner while it’s being processed, and an error indicator if something went wrong

You can also explicitly instruct the agent to use [searchKnowledgeBase] at specific moments in your prompt if you want more control over when searches happen.

How to Prompt

​Quick Start

Quick Start