Press_digit Always Returns success: false - DTMF Never Works

Support Help
1

Summary

The press_digit tool is configured and being called, but every single call returns success: false. DTMF tones are never actually sent. This affects ALL carriers, not just one.

Evidence

Reviewed last 20 calls across multiple carriers. Every press_digit call fails:

  • call_8e9633aa7b2eda4d15f1be486f8 (UNUM) - press_digit at 52.1s, success: false

  • call_46c5f2c63d4a24601fc901247ae (Delta Dental) - press_digit at 23.9s, success: false

  • call_041f4df9ab26187362b05f0d7ed (Delta Dental) - 20+ press_digit calls, ALL success: false

Why Some Calls Still Succeed

Carriers like Delta Dental accept voice input (“Provider”, “Yes”, “All benefits”), so the AI navigates via speech. Carriers like UNUM require actual button presses (“please press one”)

and fail completely since DTMF never sends.

Our Configuration

  • Agent ID: agent_f8a7bc4f9b59a506bc5b9aa7df

  • LLM ID: llm_87d92f945f2014ad446b32281418

  • Model: claude-4.5-haiku

  • press_digit is in general_tools with type: “press_digit” \

Tool Definition

{“name”:“press_digit”,“type”:“press_digit”,“description”:"Press a digit on the phone keypad for IVR

navigation",“parameters”:{“type”:“object”,“properties”:{“digit”:{“type”:“string”,“enum”:[“0”,“1”,“2”,“3”,“4”,“5”,“6”,“7”,“8”,“9”,“*”,“#”]}},“required”:[“digit”]}}

Questions

1. What does success: false mean? Is DTMF not being sent at all?

2. Is there additional configuration needed beyond adding press_digit to general_tools?

3. Is this a known issue with certain phone number types or telephony providers?

4. Can you check our account/agent configuration to see what’s wrong?

Impact

This blocks all calls to carriers requiring DTMF input (UNUM, likely others). We need DTMF working for production.

Issue with press_digit not triggering in IVR – Call IDs attached
2

Based on the documentation, the Press Digit functionality is designed specifically for IVR navigation with DTMF input(1). Your tool configuration appears correct, but there are some important setup requirements and known issues to consider.

Required Configuration

To enable Press Digit functionality, you need to(1):

  1. Add a Press Digit Tool to your agent
  2. Add prompts to guide the agent when and what digit to press(1)

The prompt guidance is critical. You can write prompts like(1):

You are going to call to a business and they may have IVR setup.
Listen carefully to their setup and press the right digit to navigate 
the IVR to reach the support department.

(1)

Or if you know the digit beforehand(1):

Press digit 1 to reach the support department.

(1)

Known Issues

There are documented cases where press digit functionality doesn’t work with certain IVRs(2). Users have reported that IVRs don’t recognize button presses from Retell, even though manual cellphone digit presses work on the same IVRs(2).

Additionally, there’s a known limitation where the agent needs to wait for the IVR to finish before it can decide what to do next(3). If you encounter an endless loop recording that never pauses, the agent may sit idle doing nothing(3).

API Requirements

This functionality only works with Call API v2(1). If you’re using older API versions, you need to migrate following the migration guide(1).

What success: false Likely Means

While the exact meaning of success: false isn’t explicitly documented in the available sources, based on the known issues with IVR recognition(2), this likely indicates that the DTMF tone transmission failed or wasn’t acknowledged by the receiving system.

Next Steps

Since this appears to be affecting all carriers in your setup, I recommend:

3

Hello @neehar

I’ve checked the calls you sent, and the agent actually pressed the button

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What might happen is that it could be pressed too early

What you can do is to increase the pause time before pressing.

Test by adding an extra 500-2000 above the current time

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