Added dedicated pages for the end call tool

fern/apis/api/openapi-overrides.yml

@@ -631,6 +631,14 @@ components:
         Configuration used to create an assistant, including its model, voice,
         transcriber, prompts, tools, messaging, and conversation behavior.
       properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
         firstMessageInterruptionsEnabled:
           description: >-
             Set to `true` to allow the user to interrupt the assistant while it
@@ -653,6 +661,14 @@ components:
         Per-call or handoff overrides for an assistant's providers, messages,
         tools, credentials, call behavior, and server configuration.
       properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
         firstMessageInterruptionsEnabled:
           description: >-
             Set to `true` to allow the user to interrupt the assistant while it
@@ -678,6 +694,14 @@ components:
         how the assistant listens, reasons, speaks, handles conversations,
         sends events, and produces artifacts and analysis.
       properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
         firstMessageInterruptionsEnabled:
           description: >-
             Set to `true` to allow the user to interrupt the assistant while it
@@ -700,6 +724,14 @@ components:
         Fields used to update an existing assistant. Include only the settings
         you want to change; omitted fields retain their current values.
       properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
         firstMessageInterruptionsEnabled:
           description: >-
             Set to `true` to allow the user to interrupt the assistant while it
@@ -717,6 +749,46 @@ components:
             x-fern-enum:
               "transcript[transcriptType='final']":
                 name: FinalTranscript
+    AssistantDraft:
+      properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
+    AssistantVersion:
+      properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
+    CreateAssistantDraftDTO:
+      properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
+    UpdateAssistantDraftDTO:
+      properties:
+        endCallMessage:
+          description: >-
+            The message the assistant says when it ends the call with the Hang Up
+            tool (`endCall`) and that tool has no messages. If the tool has a
+            `request-start` message, the assistant says that message instead. If
+            this field is unspecified or empty, the assistant says "Goodbye" in the
+            transcriber's language. When an assistant hook runs `endCall`, this
+            field isn't used and the assistant says "Goodbye" in English.
     CreateSquadDTO:
       description: >-
         Configuration used to create a squad. Provide an ordered list of

fern/assistants/end-call-phrases.mdx

@@ -6,6 +6,10 @@ description: End call phrases let assistants end calls after saying configured t
 
 End call phrases are configured phrases that end a call after the assistant says them. A customer can initiate the closing exchange by saying goodbye, but the customer's words do not trigger the match directly. The assistant must respond with a configured phrase, such as "have a good day."
 
+<Info>
+To let the model decide when to end the call instead, use the [Hang Up tool](/tools/hang-up). For the differences between end call phrases and the Hang Up tool, see [Compare the Hang Up tool and end call phrases](/tools/hang-up#compare-the-hang-up-tool-and-end-call-phrases).
+</Info>
+
 The typical sequence is:
 
 1. The customer indicates that the conversation is over.
@@ -29,7 +33,11 @@ Avoid unnecessary punctuation and whitespace inside a phrase. A short phrase suc
   </Step>
 
   <Step title="Find the end call settings">
-    In the assistant editor, find **End Call Message** and **End Call Phrases**.
+    In the assistant editor, open the **Advanced** tab and find **End Call Message** and **End Call Phrases**.
+
+    <Frame caption="End Call Message and End Call Phrases in the Advanced tab">
+      <img src="/static/images/tools/hang-up/06-end-call-phrases.png" alt="Vapi Dashboard Advanced tab with End Call Message set to Goodbye and End Call Phrases set to Thanks for calling. Goodbye." />
+    </Frame>
   </Step>
 
   <Step title="Enter end call phrases">
@@ -69,14 +77,14 @@ Use phrases that are specific to the end of a conversation. Test each phrase aga
 | `done` | `we are all done for today` | The longer phrase describes a clear conclusion. |
 | `thanks` | `thank you for calling` | The specific phrase is less likely to match a routine acknowledgment. |
 
-## Compare end call phrases and the End Call Tool
+## Compare end call phrases and the Hang Up tool
 
 Both options let an assistant end a call, but they support different decision patterns.
 
 | Option | Use when |
 | --- | --- |
 | End call phrases | The assistant uses simple, predictable spoken conclusions. |
-| [End Call Tool](/tools/default-tools#end-call) | The model must decide when to end the call using conversation context or more complex conditions. |
+| [Hang Up tool](/tools/hang-up) | The model must decide when to end the call using conversation context or more complex conditions. |
 
 ## Troubleshoot unexpected call endings
 
@@ -91,6 +99,7 @@ See [call end reasons](/calls/call-ended-reason) for the complete list of ended
 
 ## Related
 
+- [Hang Up tool](/tools/hang-up)
 - [Built-in tools](/tools/default-tools)
 - [Call end reasons](/calls/call-ended-reason)
 - [Troubleshoot call errors](/calls/troubleshoot-call-errors)

fern/calls/call-ended-reason.mdx

@@ -84,7 +84,7 @@ These occur before the call connects, during resource setup.
 
 These indicate the assistant intentionally ended the call — not errors.
 
-- `assistant-ended-call` — The assistant ended the call (via an end-call tool or function).
+- `assistant-ended-call` — The assistant ended the call (via the [Hang Up tool](/tools/hang-up) or function).
 - `assistant-ended-call-after-message-spoken` — The assistant ended the call after speaking its final message.
 - `assistant-ended-call-with-hangup-task` — The assistant ended the call using a hangup task.
 - `assistant-said-end-call-phrase` — The assistant said a phrase configured to trigger call termination.

fern/docs.yml

@@ -261,6 +261,14 @@ navigation:
                     path: tools/transfer-call/warm-transfer.mdx
                   - page: Assistant-based warm transfer
                     path: calls/assistant-based-warm-transfer.mdx
+              - section: Hang Up tool
+                path: tools/hang-up.mdx
+                icon: fa-light fa-phone-hangup
+                contents:
+                  - page: Hang Up tool quickstart
+                    path: tools/hang-up/quickstart.mdx
+                  - page: Configure the Hang Up tool
+                    path: tools/hang-up/configuration.mdx
               - section: Handoff tool
                 path: squads/handoff.mdx
                 icon: fa-light fa-hand-holding-hand

fern/gpt-live/overview.mdx

@@ -65,7 +65,7 @@ For you, more of the design lives in the two prompts:
 Vapi connects GPT-Live to your phone numbers and tools, and provides call records and observability according to your recording and data settings:
 
 - Browser, Twilio, Vapi SIP, and WebSocket calls.
-- Function, API request, and MCP tools, Google Calendar, Google Sheets, and Slack tools, plus built-in end-call, transfer, and DTMF tools.
+- Function, API request, and MCP tools, Google Calendar, Google Sheets, and Slack tools, plus built-in Hang Up, transfer, and DTMF tools.
 - Speaker and reasoner prompts, reasoner skills, personality packs, and 22 voices.
 - Idle-message hooks and HTTP live call control.
 - Transcripts, recordings, structured outputs, scorecards, Boards, Monitoring, and Voice Simulations.

fern/gpt-live/quickstart.mdx

@@ -53,8 +53,8 @@ In **Reasoner**, enter:
 Call endCall when the caller asks to end the call or says goodbye.
 ```
 </Step>
-<Step title="Add the end-call tool">
-Add the built-in **End Call** tool to the assistant.
+<Step title="Add the Hang Up tool">
+Add the built-in **Hang Up** tool to the assistant.
 </Step>
 <Step title="Set the greeting and publish">
 Set the first message to "Hi, this is Example Service Studio. Who am I speaking with?" and set the assistant to speak first. Select **Publish**.

fern/prompting-guide.mdx

@@ -368,7 +368,7 @@ The LLM's ability to use tools correctly depends entirely on how well you descri
 }
 ```
 
-Always set an explicit `description` on transfer and end-call tools. If you leave them blank, the auto-generated description may bias the model against calling them. See [Built-in tools](/tools/default-tools) for details on transfer and end-call tools.
+Always set an explicit `description` on Transfer Call and Hang Up tools. If you leave them blank, the auto-generated description may bias the model against calling them. See [Transfer Call tool](/tools/transfer-call) and [Hang Up tool](/tools/hang-up) for details.
 
 Keep tool responses short and structured. Anything you return is visible to the LLM on the next turn — don't include fields the model doesn't need, and never return sensitive values you don't want in conversation history.
 

fern/tools/default-tools.mdx

@@ -1,8 +1,8 @@
 ---
 title: Built-in tools
-subtitle: 'Adding Transfer Call, End Call, Dial Keypad, and API Request capabilities to your assistants'
+subtitle: 'Adding Transfer Call, Hang Up, Dial Keypad, and API Request capabilities to your assistants'
 slug: tools/default-tools
-description: Add Vapi's built-in default tools to assistants, including transfer call, end call, SMS, DTMF keypad, and API request, through the API or dashboard.
+description: Add Vapi's built-in default tools to assistants, including transfer call, hang up, SMS, DTMF keypad, and API request, through the API or dashboard.
 ---
 
 Vapi voice assistants are given additional functions: `transferCall`, `endCall`, `sms`, `dtmf` (to dial a keypad with [DTMF](https://en.wikipedia.org/wiki/DTMF)), and `apiRequest`. These functions can be used to transfer calls, hang up calls, send SMS messages, enter digits on the keypad, and integrate business logic with your existing APIs.
@@ -17,29 +17,11 @@ To add built-in tools to your agent, you need to add them in the `tools` array o
   Create a transfer call tool, configure its destinations, and choose a transfer mode.
 </Card>
 
-#### End Call
+#### Hang Up
 
-This function is provided when `endCall` is included in the assistant's list of available tools (see configuration options [here](/api-reference/assistants/create#request.body.model.openai.tools.endCall)). The assistant can use this function to end the call.
-
-```json
-{
-  "model": {
-    "provider": "openai",
-    "model": "gpt-4o",
-    "messages": [
-      {
-        "role": "system",
-        "content": "You are an assistant at a law firm. If the user is being mean, use the endCall function."
-      }
-    ],
-    "tools": [
-      {
-          "type": "endCall"
-      }
-    ]
-  }
-}
-```
+<Card title="Hang Up tool" icon="fa-light fa-phone-hangup" href="/tools/hang-up">
+  Let the assistant end the call, set its goodbye message, and guard against calls that end too early.
+</Card>
 
 #### Send Text