Quick Start
Define when to use it
In your system prompt, clearly explain when the agent should (and shouldn’t) use the tool
In the prompt, define when the agent should use a tool — not how the tool works technically. The technical configuration is handled separately in the agent settings.
How Tool Calls Work
- The agent decides — Based on your prompt instructions, the LLM determines a tool should be called
- The tool executes — The tool runs in the background; the customer never sees or hears the tool name
- The agent continues — The agent receives the result and continues the conversation naturally
Built-in Tools
These tools are available to every agent out of the box:| Tool | What It Does |
|---|---|
[endCall] | Ends the call |
[callMeLater] | Schedules a callback at a later time |
[waitForUserToReturn] | Pauses and waits for the customer to come back |
[searchKnowledgeBase] | Searches the agent’s knowledge base |
Custom HTTP Tools
Custom tools allow your agent to call external APIs during a conversation — for example, looking up an account balance, checking appointment availability, or updating a CRM record. Custom tools are configured in the Tools section of your agent settings. See Custom HTTP Tools for setup instructions.How to Prompt Custom Tools
To help agents clearly understand when and how to use tool calls, each tool includes a “Description” (Global tool prompt) tab within its configuration page. There is also an LLM Variable prompt which can reference previous tool calls or define format. A detailed description:- Clearly explains when the tool should be used
- Defines how it should be used
- Specifies any important conditions, constraints, or input expectations
- Reduces ambiguity for the agent
Best Practices for Prompting Tool Usage
Define When to Use
For each tool, clearly define in the system prompt: → When the agent should use it → When the agent should not use it → What to say to the customer before/after using it (if anything)Never Speak Tool Names Out Loud
Instructions in square brackets are internal actions. The customer only hears the natural-language result.Do say: “Let me quickly look that up for you…”Keep it natural and conversational.
Place Instructions Close to Usage
If a tool is related to a specific section of your script (e.g., knowledge base search is related to troubleshooting), put the usage instructions in that section — not buried in a generic rules list far away.Give Concrete Examples
Don’t just say “use the knowledge base with Artikelnummer.” Show the agent exactly what a correct query looks like.Do write: “When the customer is in the installation flow, always include the article number in your search query. Example:
fulltext_query: 'Artikelnummer 000012345 Sky Stream Installation kein Bild'”Clear, specific, with a concrete example.Define Negative Cases
For every “when to use,” also define “when NOT to use.” This prevents the agent from over-using or mis-using tools.Example Usage Rules
| Tool | Action | Usage Rules | Example Situation |
|---|---|---|---|
[endCall] | Agent ends the call | Only after all tasks are completed and the conversation is fully concluded. | The right person is not available |
[callMeLater] | Agent schedules a callback | Always ask the customer first if they want a callback. Never call the tool before asking. Never use for expert callbacks. If the words “expert,” “colleague,” or “transfer” were used, this tool is forbidden. | The user is busy and wants to be called back later |
[waitForUserToReturn] | Waits for the customer | Use when giving instructions and waiting for the customer to act, or when the customer asks you to wait. | Agent: “Plug in the cable.” User: “One moment, I’ll be right back.” |
[searchKnowledgeBase] | Searches knowledge base | Use before giving technical instructions. Never use after already giving instructions. | Customer asks a product question not covered in the prompt |