VAP-3931 Added more transferPlan details and along with twiml notes

Author: ramsrib

fern/call-forwarding.mdx

@@ -3,7 +3,6 @@ title: Call Forwarding
 slug: call-forwarding
 ---
 
-
 Vapi's call forwarding functionality allows you to redirect calls to different phone numbers based on specific conditions using tools. This guide explains how to set up and use the `transferCall` function for call forwarding.
 
 ## Key Concepts
@@ -53,17 +52,11 @@ The `transferCall` tool includes a list of destinations and corresponding messag
           "properties": {
             "destination": {
               "type": "string",
-              "enum": [
-                "+1234567890",
-                "+0987654321",
-                "+1122334455"
-              ],
+              "enum": ["+1234567890", "+0987654321", "+1122334455"],
               "description": "The destination to transfer the call to."
             }
           },
-          "required": [
-            "destination"
-          ]
+          "required": ["destination"]
         }
       },
       "messages": [
@@ -119,7 +112,6 @@ When the assistant needs to forward a call, it uses the `transferCall` function
     }
   }
 }
-
 ```
 
 ### 3. Customizing Messages
@@ -142,7 +134,6 @@ Customize the messages for each destination to provide clear information to the
     }
   ]
 }
-
 ```
 
 ## Instructing the Assistant
@@ -176,12 +167,13 @@ To implement a warm transfer, add a `transferPlan` object to the `transferCall`
 
 In this mode, Vapi provides a summary of the call to the recipient before transferring.
 
-* **Configuration:**
-   * Set the `mode` to `"warm-transfer-with-summary"`.
-   * Define a `summaryPlan` specifying how the summary should be generated.
-   * Use the `{{transcript}}` variable to include the call transcript.
+- **Configuration:**
+
+  - Set the `mode` to `"warm-transfer-with-summary"`.
+  - Define a `summaryPlan` specifying how the summary should be generated.
+  - Use the `{{transcript}}` variable to include the call transcript.
 
-* **Example:**
+- **Example:**
 
 ```json
 "transferPlan": {
@@ -204,14 +196,15 @@ In this mode, Vapi provides a summary of the call to the recipient before transf
 
 #### 2. Warm Transfer with Message
 
-In this mode, Vapi delivers a custom static message to the recipient before transferring the call.
+In this mode, Vapi delivers a custom message to the recipient before transferring the call.
+
+- **Configuration:**
 
-* **Configuration:**
-   * Set the `mode` to `"warm-transfer-with-message"`.
-   * Provide the custom message in the `message` property.
-   * Note that the `{{transcript}}` variable is not available in this mode.
+  - Set the `mode` to `"warm-transfer-with-message"`.
+  - Provide the custom message in the `message` property.
+  - Note that the `{{transcript}}` variable is not available in this mode.
 
-* **Example:**
+- **Example:**
 
 ```json
 "transferPlan": {
@@ -259,17 +252,69 @@ Here is a full example of a `transferCall` payload using the warm transfer with
 }
 ```
 
-#### 3. Warm Transfer with TwiML
+#### 3. Warm Transfer with Wait and Say Message
+
+In this mode, Vapi waits for the recipient to speak first and then delivers a custom message to the recipient before transferring the call.
+
+- **Configuration:**
+
+  - Set the `mode` to `"warm-transfer-wait-for-operator-to-speak-first-and-then-say-message"`.
+  - Provide the custom message in the `message` property.
+  - Note that the `{{transcript}}` variable is not available in this mode.
+
+- **Example:**
+
+```json
+"transferPlan": {
+  "mode": "warm-transfer-wait-for-operator-to-speak-first-and-then-say-message",
+  "message": "Hey, this call has been forwarded through Vapi."
+}
+```
+
+#### 4. Warm Transfer with Wait and Say Summary
+
+In this mode, Vapi waits for the recipient to speak first and then delivers a summary of the call to the recipient before transferring the call.
+
+- **Configuration:**
+
+  - Set the `mode` to `"warm-transfer-wait-for-operator-to-speak-first-and-then-say-summary"`.
+  - Define a `summaryPlan` specifying how the summary should be generated.
+  - Use the `{{transcript}}` variable to include the call transcript.
+
+- **Example:**
+
+```json
+"transferPlan": {
+  "mode": "warm-transfer-wait-for-operator-to-speak-first-and-then-say-summary",
+  "summaryPlan": {
+    "enabled": true,
+    "messages": [
+      {
+        "role": "system",
+        "content": "Please provide a summary of the call."
+      },
+      {
+        "role": "user",
+        "content": "Here is the transcript:\n\n{{transcript}}\n\n"
+      }
+    ]
+  }
+}
+```
+
+#### 5. Warm Transfer with TwiML
 
 In this mode, Vapi executes TwiML instructions on the destination call leg before connecting the destination number.
 
-* **Configuration:**
-   * Set the `mode` to `"warm-transfer-with-twiml"`.
-   * Provide the TwiML instructions in the `twiml` property.
-   * Supports only `Play`, `Say`, `Gather`, `Hangup`, and `Pause` verbs.
-   * Maximum TwiML length is 4096 characters.
+- **Configuration:**
 
-* **Example:**
+  - Set the `mode` to `"warm-transfer-with-twiml"`.
+  - Provide the TwiML instructions in the `twiml` property.
+  - Supports only `Play`, `Say`, `Gather`, and `Pause` verbs.
+  - Maximum TwiML length is 4096 characters.
+  - TwiML must be provided as a single-line string without line breaks or tabs.
+
+- **Example:**
 
 ```json
 "transferPlan": {
@@ -278,7 +323,6 @@ In this mode, Vapi executes TwiML instructions on the destination call leg befor
 }
 ```
 
-
 Here is a full example of a `transferCall` payload using the warm transfer with TwiML mode:
 
 ```json