diff --git a/templates/zerver/api/construct-narrow.md b/templates/zerver/api/construct-narrow.md
index aa24f67f86..e8e001053a 100644
--- a/templates/zerver/api/construct-narrow.md
+++ b/templates/zerver/api/construct-narrow.md
@@ -42,23 +42,31 @@ search](/help/search-for-messages).  There are a few additional
 options, new in Zulip 2.1, that we don't document there because they
 are primarily useful to API clients:
 
-* `pm-with:1234`: Search 1-on-1 messages between you and user ID `1234`.
-* `sender:1234`: Search 1-on-1 messages sent by user ID `1234`.
-* `stream:1234`: Search 1-on-1 messages sent to the stream with ID `123`.
-* `group-pm-with:1234`: Search private messages including the user with ID `1234`.
+* `sender:1234`: Search messages sent by user ID `1234`.
+* `stream:1234`: Search messages sent to the stream with ID `123`.
+* `pm-with:1234`: Search the private message conversation between
+  you and user ID `1234`.
+* `pm-with:1234,5678`: Search the private message conversation between
+  you, user ID `1234`, and user ID `5678`.
+* `group-pm-with:1234`: Search all (group) private messages that
+  include user ID `1234`.
+* `pm-with:1234,5678`: Search all (group) private messages that
+  include user ID `1234` and user ID `5678`.
 
-For example, to query messages sent by a user 1234 to stream 123, the
-correct JSON-encoded query is:
+The operands for these search options must be encoded either as an
+integer ID or a JSON list of integer IDs.  For example, to query
+messages sent by a user 1234 to a PM thread with yourself, user 1234,
+and user 5678, the correct JSON-encoded query is:
 
 ```json
 [
     {
-        "operator": "sender",
-        "operand": 1234
+        "operator": "pm-with",
+        "operand": [1234, 5678]
     },
     {
-        "operator": "stream",
-        "operand": 123
+        "operator": "sender",
+        "operand": 1234
     }
 ]
 ```
diff --git a/templates/zerver/help/search-for-messages.md b/templates/zerver/help/search-for-messages.md
index 2f0ce13d1d..7ffed051f9 100644
--- a/templates/zerver/help/search-for-messages.md
+++ b/templates/zerver/help/search-for-messages.md
@@ -26,9 +26,7 @@ Here is the **full list of search operators**.
 * `stream:design`: Search within the stream `#design`.
 * `stream:design topic:emoji+picker`: Search within the topic `emoji picker`.
 * `is:private`: Search all your private messages.
-* `pm-with:ada@zulip.com`: Search 1-on-1 messages with Ada.
-* `group-pm-with:ada@zulip.com`: Search group private messages that
-  include Ada.
+* `pm-with:ada@zulip.com`: Search 1-on-1 private messages between you and Ada.
 * `sender:ada@zulip.com`: Search messages sent by Ada.
 * `sender:me`: Search sent messages.
 * `near:12345`: Show messages around the message with ID `12345`.
@@ -43,6 +41,10 @@ Here is the **full list of search operators**.
 * `has:link`
 * `has:image`
 * `has:attachment`
+* `pm-with:ada@zulip.com,bob@zulip.com`: Search private message conversation
+  between you, Bob, and Ada.
+* `group-pm-with:ada@zulip.com,bob@zulip.com`: Search all group
+  private messages that include Ada and Bob.
 
 ## Words and phrases