From 6b0c26e4c4d4ce4d00f1fcadd083f959b3e7bb68 Mon Sep 17 00:00:00 2001
From: Stephen Hand <steveh@techmatters.org>
Date: Fri, 16 Jan 2026 13:18:03 +0000
Subject: [PATCH] Return 404 when participant not found in conferencing
 endpoints

---
 .../src/conference/getParticipant.ts          | 31 ++++++++++++++-----
 .../src/conference/removeParticipant.ts       | 31 ++++++++++++++-----
 .../src/conference/updateParticipant.ts       | 23 ++++++++++++--
 3 files changed, 68 insertions(+), 17 deletions(-)

diff --git a/lambdas/account-scoped/src/conference/getParticipant.ts b/lambdas/account-scoped/src/conference/getParticipant.ts
index c8ee471504..144a445c22 100644
--- a/lambdas/account-scoped/src/conference/getParticipant.ts
+++ b/lambdas/account-scoped/src/conference/getParticipant.ts
@@ -17,7 +17,8 @@
 import { AccountScopedHandler } from '../httpTypes';
 import { newMissingParameterResult } from '../httpErrors';
 import { getTwilioClient } from '@tech-matters/twilio-configuration';
-import { newOk } from '../Result';
+import { newErr, newOk } from '../Result';
+import type RestException from 'twilio/lib/base/RestException';
 
 export type Body = {
   callSid: string;
@@ -34,10 +35,26 @@ export const getParticipantHandler: AccountScopedHandler = async (
   if (!callSid) return newMissingParameterResult('callSid');
   if (!conferenceSid) return newMissingParameterResult('conferenceSid');
   const client = await getTwilioClient(accountSid);
-  const participant = await client.conferences
-    .get(conferenceSid)
-    .participants.get(callSid)
-    .fetch();
-
-  return newOk({ participant });
+  try {
+    const participant = await client.conferences
+      .get(conferenceSid)
+      .participants.get(callSid)
+      .fetch();
+    return newOk({ participant });
+  } catch (error) {
+    const restError = error as RestException;
+    if (restError.status === 404) {
+      const message = `Participant with call sid ${callSid} not found on ${accountSid}/${conferenceSid}`;
+      // Often errors of this type are thrown but the recording appears to pause at the correct point.
+      console.warn(message, error);
+      return newErr({
+        message,
+        error: {
+          cause: restError,
+          statusCode: 404,
+        },
+      });
+    }
+    throw error;
+  }
 };
diff --git a/lambdas/account-scoped/src/conference/removeParticipant.ts b/lambdas/account-scoped/src/conference/removeParticipant.ts
index ac3185565f..e59db9cfc9 100644
--- a/lambdas/account-scoped/src/conference/removeParticipant.ts
+++ b/lambdas/account-scoped/src/conference/removeParticipant.ts
@@ -16,8 +16,9 @@
 
 import { AccountScopedHandler } from '../httpTypes';
 import { getTwilioClient } from '@tech-matters/twilio-configuration';
-import { newOk } from '../Result';
+import { newErr, newOk } from '../Result';
 import { newMissingParameterResult } from '../httpErrors';
+import type RestException from 'twilio/lib/base/RestException';
 
 export type Body = {
   callSid: string;
@@ -35,10 +36,26 @@ export const removeParticipantHandler: AccountScopedHandler = async (
   if (!conferenceSid) return newMissingParameterResult('conferenceSid');
 
   const client = await getTwilioClient(accountSid);
-  const participantRemoved = await client
-    .conferences(conferenceSid)
-    .participants(callSid)
-    .remove();
-
-  return newOk({ message: `Participant removed: ${participantRemoved}` });
+  try {
+    const participantRemoved = await client
+      .conferences(conferenceSid)
+      .participants(callSid)
+      .remove();
+    return newOk({ message: `Participant removed: ${participantRemoved}` });
+  } catch (error) {
+    const restError = error as RestException;
+    if (restError.status === 404) {
+      const message = `Participant with call sid ${callSid} not found on ${accountSid}/${conferenceSid}`;
+      // Often errors of this type are thrown but the recording appears to pause at the correct point.
+      console.warn(message, error);
+      return newErr({
+        message,
+        error: {
+          cause: restError,
+          statusCode: 404,
+        },
+      });
+    }
+    throw error;
+  }
 };
diff --git a/lambdas/account-scoped/src/conference/updateParticipant.ts b/lambdas/account-scoped/src/conference/updateParticipant.ts
index 367dcd8099..301996b1f1 100644
--- a/lambdas/account-scoped/src/conference/updateParticipant.ts
+++ b/lambdas/account-scoped/src/conference/updateParticipant.ts
@@ -17,7 +17,8 @@
 import { AccountScopedHandler } from '../httpTypes';
 import { newMissingParameterResult } from '../httpErrors';
 import { getTwilioClient } from '@tech-matters/twilio-configuration';
-import { newOk } from '../Result';
+import { newErr, newOk } from '../Result';
+import type RestException from 'twilio/lib/base/RestException';
 
 const validUpdates = ['endConferenceOnExit', 'hold', 'muted'] as const;
 
@@ -56,8 +57,24 @@ export const updateParticipantHandler: AccountScopedHandler = async (
     .conferences(conferenceSid)
     .participants(callSid)
     .fetch();
-
-  await participant.update(parsedUpdates);
+  try {
+    await participant.update(parsedUpdates);
+  } catch (error) {
+    const restError = error as RestException;
+    if (restError.status === 404) {
+      const message = `Participant with call sid ${callSid} not found on ${accountSid}/${conferenceSid}`;
+      // Often errors of this type are thrown but the recording appears to pause at the correct point.
+      console.warn(message, error);
+      return newErr({
+        message,
+        error: {
+          cause: restError,
+          statusCode: 404,
+        },
+      });
+    }
+    throw error;
+  }
 
   return newOk({ message: `Participant updated: ${updates}` });
 };