From c15fbde99a1eccb0237e6e478ce3cf7ab772aa48 Mon Sep 17 00:00:00 2001 From: Cursor Agent Date: Thu, 11 Sep 2025 22:11:55 +0000 Subject: [PATCH 1/3] Docs: Add assistant-request webhook timeout warning Co-authored-by: sahil --- fern/server-url/events.mdx | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fern/server-url/events.mdx b/fern/server-url/events.mdx index 98761bdfb..1444bb631 100644 --- a/fern/server-url/events.mdx +++ b/fern/server-url/events.mdx @@ -113,6 +113,14 @@ For inbound phone calls, you can specify the assistant dynamically. If a PhoneNu } ``` + + You must respond to the `assistant-request` webhook within 7.5 seconds end-to-end (from when we send the request to when your response reaches your server). This limit is fixed and not configurable: Twilio enforces a 15-second cap, and Vapi reserves ~7.5 seconds for call setup. The timeout value shown elsewhere in the dashboard does not apply to this webhook. + + To avoid timeouts: + - Return quickly with an existing assistantId or a minimal assistant, then enrich context asynchronously after the call starts using Live Call Control. + - Host your webhook close to us-west-2 to reduce latency, and target < ~6s to allow for network jitter. + + Respond with either an existing assistant ID, a transient assistant, or transfer destination: ```json From f5552c3758d435e7d819a636f59c0b3fd2e696c2 Mon Sep 17 00:00:00 2001 From: Cursor Agent Date: Thu, 11 Sep 2025 22:14:26 +0000 Subject: [PATCH 2/3] Fix webhook timeout description Co-authored-by: sahil --- fern/server-url/events.mdx | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fern/server-url/events.mdx b/fern/server-url/events.mdx index 1444bb631..f74345807 100644 --- a/fern/server-url/events.mdx +++ b/fern/server-url/events.mdx @@ -114,7 +114,7 @@ For inbound phone calls, you can specify the assistant dynamically. If a PhoneNu ``` - You must respond to the `assistant-request` webhook within 7.5 seconds end-to-end (from when we send the request to when your response reaches your server). This limit is fixed and not configurable: Twilio enforces a 15-second cap, and Vapi reserves ~7.5 seconds for call setup. The timeout value shown elsewhere in the dashboard does not apply to this webhook. + You must respond to the `assistant-request` webhook within 7.5 seconds end-to-end. This limit is fixed and not configurable: Twilio enforces a 15-second cap, and Vapi reserves ~7.5 seconds for call setup. The timeout value shown elsewhere in the dashboard does not apply to this webhook. To avoid timeouts: - Return quickly with an existing assistantId or a minimal assistant, then enrich context asynchronously after the call starts using Live Call Control. From 3ad1124d366baca0457ce3f854001977326db871 Mon Sep 17 00:00:00 2001 From: Cursor Agent Date: Thu, 11 Sep 2025 22:15:48 +0000 Subject: [PATCH 3/3] Fix: Clarify webhook timeout reasons Co-authored-by: sahil --- fern/server-url/events.mdx | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fern/server-url/events.mdx b/fern/server-url/events.mdx index f74345807..4f4fa615c 100644 --- a/fern/server-url/events.mdx +++ b/fern/server-url/events.mdx @@ -114,7 +114,7 @@ For inbound phone calls, you can specify the assistant dynamically. If a PhoneNu ``` - You must respond to the `assistant-request` webhook within 7.5 seconds end-to-end. This limit is fixed and not configurable: Twilio enforces a 15-second cap, and Vapi reserves ~7.5 seconds for call setup. The timeout value shown elsewhere in the dashboard does not apply to this webhook. + You must respond to the `assistant-request` webhook within 7.5 seconds end-to-end. This limit is fixed and not configurable: the telephony provider enforces a 15-second cap, and Vapi reserves ~7.5 seconds for call setup. The timeout value shown elsewhere in the dashboard does not apply to this webhook. To avoid timeouts: - Return quickly with an existing assistantId or a minimal assistant, then enrich context asynchronously after the call starts using Live Call Control.