​ To learn more, see the sources I considered: [[1] Integrate any system with custom function](https://docs.retellai.com/build/single-multi-prompt/custom-function) [[2] MCP's Speak During Execution is not working.](https://discord.com/channels/1186424376300679209/1411987278842298409) ​

### Answer --- The "Speak During Execution" setting is available when configuring custom functions in Retell AI. [(1) ]() For custom functions, you configure this in the dashboard under step 9 when setting up the function: - **Speak during execution**: Controls whether the agent speaks the moment the function is called. Enable it for user-facing actions (e.g., getting weather information) so the agent can say something like "Let me check that for you." However, based on the available sources, I don't have specific documentation on how to enable "Speak During Execution" for in-house Cal.com tools specifically. The documentation only covers this setting for custom functions you create yourself. If Cal.com is integrated as a built-in tool or via MCP, note that some users have reported issues with "Speak During Execution" not working consistently for MCP tools. [(2) ]() A workaround mentioned is to use custom functions instead, where the speak during execution option is available in the UI. **Recommendation**: If you need reliable "speak during execution" behavior, consider implementing your Cal.com integration as a custom function rather than using a built-in tool. Check out these potentially useful sources: - [Integrate any system with custom function]() Would you like a general answer on how to set up Cal.com as a custom function?

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.