voicemail mixing warning

Author: bajajcodes

fern/calls/customer-join-timeout.mdx

@@ -1,13 +1,13 @@
 ---
-title: Customer join timeout
+title: Customer Join Timeout
 subtitle: Configure web call join timeout for better success rates
 slug: calls/customer-join-timeout
 description: Set maximum time for users to join web calls before automatic termination
 ---
 
 ## Overview
 
-**Customer join timeout** sets the maximum time users have to join a web call before it's automatically terminated. This parameter helps you optimize call success rates by accounting for real-world connection challenges.
+**Customer Join Timeout** sets the maximum time users have to join a web call before it's automatically terminated. This parameter helps you optimize call success rates by accounting for real-world connection challenges.
 
 **You'll learn to:**
 
@@ -269,7 +269,7 @@ A user attempting to join needs:
   Start with 30-60 seconds and adjust based on your success rate analytics.
 </Tip>
 
-### "Meeting has ended" message
+### Meeting has ended message
 
 This message appears when a call ends naturally and is **informational only**—not an error.
 

fern/docs.yml

@@ -130,7 +130,6 @@ navigation:
             contents:
               - page: Transient vs permanent configurations
                 path: assistants/concepts/transient-vs-permanent-configurations.mdx
-                icon: fa-light fa-toggle-on
           - section: Conversation behavior
             icon: fa-light fa-comments
             contents:
@@ -144,7 +143,6 @@ navigation:
                 path: assistants/voice-formatting-plan.mdx
               - page: Flush syntax
                 path: assistants/flush-syntax.mdx
-                icon: fa-light fa-forward
               - page: Background messages
                 path: assistants/background-messages.mdx
               - page: Idle messages
@@ -162,7 +160,6 @@ navigation:
                 path: customization/speech-configuration.mdx
               - page: Voice pipeline configuration
                 path: customization/voice-pipeline-configuration.mdx
-                icon: fa-light fa-waveform-lines
               - page: Voice fallback plan
                 path: voice-fallback-plan.mdx
               - page: OpenAI realtime speech-to-speech
@@ -409,7 +406,6 @@ navigation:
                 path: calls/call-features.mdx
               - page: Customer join timeout
                 path: calls/customer-join-timeout.mdx
-                icon: fa-light fa-clock
               - page: Voicemail detection
                 path: calls/voicemail-detection.mdx
           - section: Transfer calls

fern/tools/voicemail-tool.mdx

@@ -5,14 +5,17 @@ slug: tools/voicemail-tool
 ---
 
 <Warning>
-**Beta Feature**: The voicemail tool is currently in beta. Features and behavior may change as we continue to improve this functionality based on user feedback.
+  **Beta Feature**: The voicemail tool is currently in beta. Features and
+  behavior may change as we continue to improve this functionality based on user
+  feedback.
 </Warning>
 
 ## Overview
 
 The voicemail tool gives your assistant direct control over when and how to leave voicemail messages. Unlike [automatic voicemail detection](/calls/voicemail-detection), which operates independently of your assistant, this tool allows your assistant to decide when it's reached a voicemail system and leave a configured message.
 
 **Key benefits:**
+
 - **Maximum flexibility** - Assistant decides when and what to say
 - **Cost-effective** - Only triggers when needed
 - **Context-aware** - Messages can be customized based on conversation
@@ -28,7 +31,10 @@ When you add the voicemail tool to your assistant:
 4. The call ends automatically after message delivery
 
 <Note>
-This approach differs from [automatic voicemail detection](/calls/voicemail-detection), which detects voicemail at the system level. The voicemail tool puts detection and response entirely in the assistant's hands.
+  This approach differs from [automatic voicemail
+  detection](/calls/voicemail-detection), which detects voicemail at the system
+  level. The voicemail tool puts detection and response entirely in the
+  assistant's hands.
 </Note>
 
 ## Configuration
@@ -71,30 +77,31 @@ import { VapiClient } from "@vapi-ai/server-sdk";
 const vapi = new VapiClient({ token: process.env.VAPI_API_KEY });
 
 const assistant = await vapi.assistants.create({
-  model: {
-    provider: "openai",
-    model: "gpt-4o",
-    messages: [{
-      type: "system",
-      content: `You are a sales representative for Acme Corp. 
-                If at any point you determine you're speaking to a voicemail system 
-                (greeting mentions 'unavailable', 'leave a message', 'voicemail', etc.), 
-                immediately use the leave_voicemail tool.`
-    }],
-    tools: [{
-      type: "voicemail",
-      function: {
-        name: "leave_voicemail",
-        description: "Leave a voicemail message when you detect you've reached a voicemail system"
-      },
-      messages: [{
-        type: "request-start",
-        content: "Hi, this is {{company}}. {{message}}. Please call us back at {{phone}}."
-      }]
-    }]
-  }
+model: {
+provider: "openai",
+model: "gpt-4o",
+messages: [{
+type: "system",
+content: `You are a sales representative for Acme Corp.
+If at any point you determine you're speaking to a voicemail system
+(greeting mentions 'unavailable', 'leave a message', 'voicemail', etc.),
+immediately use the leave_voicemail tool.`
+}],
+tools: [{
+type: "voicemail",
+function: {
+name: "leave_voicemail",
+description: "Leave a voicemail message when you detect you've reached a voicemail system"
+},
+messages: [{
+type: "request-start",
+content: "Hi, this is {{company}}. {{message}}. Please call us back at {{phone}}."
+}]
+}]
+}
 });
-```
+
+````
 ```python title="Python SDK"
 from vapi import Vapi
 
@@ -106,9 +113,9 @@ assistant = client.assistants.create(
         "model": "gpt-4o",
         "messages": [{
             "type": "system",
-            "content": """You are a sales representative for Acme Corp. 
-                         If at any point you determine you're speaking to a voicemail system 
-                         (greeting mentions 'unavailable', 'leave a message', 'voicemail', etc.), 
+            "content": """You are a sales representative for Acme Corp.
+                         If at any point you determine you're speaking to a voicemail system
+                         (greeting mentions 'unavailable', 'leave a message', 'voicemail', etc.),
                          immediately use the leave_voicemail tool."""
         }],
         "tools": [{
@@ -124,7 +131,8 @@ assistant = client.assistants.create(
         }]
     }
 )
-```
+````
+
 </CodeBlocks>
 
 ## Message Configuration
@@ -145,7 +153,8 @@ Define the voicemail message in the tool configuration:
 ```
 
 <Tip>
-Use template variables like `{{company}}`, `{{message}}`, and `{{phone}}` to make your voicemail messages dynamic while keeping them consistent.
+  Use template variables like `{{ company }}`, `{{ message }}`, and `{{ phone }}`
+  to make your voicemail messages dynamic while keeping them consistent.
 </Tip>
 
 ### **Pre-recorded Audio Messages**
@@ -166,7 +175,8 @@ For consistent quality and pronunciation, use pre-recorded audio files by provid
 **Supported formats**: `.wav` and `.mp3` files
 
 <Note>
-Pre-recorded audio messages are ideal for brand-specific messaging or when you need precise pronunciation of phone numbers, website URLs, or company names.
+  Pre-recorded audio messages are ideal for brand-specific messaging or when you
+  need precise pronunciation of phone numbers, website URLs, or company names.
 </Note>
 
 ## Advanced Examples
@@ -237,44 +247,55 @@ Using pre-recorded audio for professional voicemail messages:
 }
 ```
 
-
-
 ## Best Practices
 
 ### Detection prompting
+
 Be specific about voicemail indicators in your system prompt:
+
 - "unavailable"
 - "leave a message"
 - "voicemail"
 - "at the tone"
 - "beep"
 
 ### Message structure
+
 Keep voicemail messages:
+
 - **Brief** - Under 30 seconds
 - **Clear** - State name, company, and purpose
 - **Actionable** - Include callback number or next steps
 - **Professional** - Match your brand voice
 
 ### Error handling
+
 Consider edge cases:
+
 - Long voicemail greetings
 - Voicemail box full scenarios
 - Systems requiring keypad input
 
 ## Voicemail Tool vs. Automatic Detection
 
-| Feature | Voicemail Tool | [Automatic Detection](/calls/voicemail-detection) |
-|---------|----------------|---------------------------------------------------|
-| Control | Assistant-driven | System-driven |
-| Flexibility | High - custom logic | Medium - predefined behavior |
-| Cost | Lower - only when used | Higher - continuous monitoring |
-| Setup complexity | Simple - just add tool | Moderate - configure detection |
-| Message customization | Full control | Limited to configured message |
-| Detection accuracy | Depends on prompt | Provider-specific (Vapi, Google, etc.) |
+| Feature               | Voicemail Tool         | [Automatic Detection](/calls/voicemail-detection) |
+| --------------------- | ---------------------- | ------------------------------------------------- |
+| Control               | Assistant-driven       | System-driven                                     |
+| Flexibility           | High - custom logic    | Medium - predefined behavior                      |
+| Cost                  | Lower - only when used | Higher - continuous monitoring                    |
+| Setup complexity      | Simple - just add tool | Moderate - configure detection                    |
+| Message customization | Full control           | Limited to configured message                     |
+| Detection accuracy    | Depends on prompt      | Provider-specific (Vapi, Google, etc.)            |
+
+<Warning>
+  Avoid combining the **voicemail tool** with **automatic detection**, as this
+  could result in false positives and other complications.
+</Warning>
 
 <Info>
-Choose the **voicemail tool** when you need maximum flexibility and cost efficiency. Choose **automatic detection** when you need guaranteed system-level detection without relying on assistant prompting.
+  Choose the **voicemail tool** when you need maximum flexibility and cost
+  efficiency. Choose **automatic detection** when you need guaranteed
+  system-level detection without relying on assistant prompting.
 </Info>
 
 ## Common Use Cases
@@ -289,4 +310,3 @@ Choose the **voicemail tool** when you need maximum flexibility and cost efficie
 - Learn about other [default tools](/tools/default-tools)
 - Explore [automatic voicemail detection](/calls/voicemail-detection) for system-level handling
 - See how to create [custom tools](/tools/custom-tools) for your specific needs
-