diff --git a/editions/tw5.com/tiddlers/Operators without parameters.tid b/editions/tw5.com/tiddlers/Operators without parameters.tid
new file mode 100644
index 000000000..756efb74e
--- /dev/null
+++ b/editions/tw5.com/tiddlers/Operators without parameters.tid	
@@ -0,0 +1,18 @@
+created: 20240708171243370
+modified: 20240708201827711
+tags: 
+title: Operators without parameters
+
+Many [[Filter Operators]] have no [[parameter|Filter Parameter]] available. Still, each operator must be followed by a bracketed parameter expression — even if it is empty — as with the <<.olink backlinks>> operator below:
+
+`[<currentTiddler>backlinks[]]`
+
+(Even though an expression such as `[<currentTiddler>backlinks]` may at first <<.em seem>> well-formed — insofar as closing brackets seem to pair properly with opening brackets — each operator needs its own parameter brackets, even if empty. See [[Filter Syntax]].)
+
+The following [[Filter Operators]] accept no parameters:
+
+<div>
+
+<<list-links filter:"[op-parameter[none]] [tag[Filter Operators]!has[op-parameter]] -[search:op-purpose[same]]" class:"multi-columns">>
+
+</div>
\ No newline at end of file
diff --git a/editions/tw5.com/tiddlers/filters/syntax/Filter Parameter.tid b/editions/tw5.com/tiddlers/filters/syntax/Filter Parameter.tid
index 9334fd069..0cfb83d5c 100644
--- a/editions/tw5.com/tiddlers/filters/syntax/Filter Parameter.tid	
+++ b/editions/tw5.com/tiddlers/filters/syntax/Filter Parameter.tid	
@@ -1,5 +1,5 @@
 created: 20150220152540000
-modified: 20230710074423650
+modified: 20240708202234843
 tags: [[Filter Step]]
 title: Filter Parameter
 type: text/vnd.tiddlywiki
@@ -29,6 +29,8 @@ The parameter to a [[filter operator|Filter Operators]] can be:
 :: The parameter is the current value of the [[variable|Variables]] whose name appears between the angle brackets. Macro parameters are <<.em not>> supported up to v5.2.0
 ::<<.from-version "5.2.0">> Literal macro parameters are supported. For example: `[<now [UTC]YYYY0MM0DD0hh0mm0ssXXX>]`.
 
+<<.note """Every [[filter Operator]] must be followed by a parameter expression. In the case of [[Operators without parameters]], that expression is empty, as with the filter Operator <<.olink links>> in `[<currentTiddler>links[]]`.""">>
+
 ---
 
 <<.from-version "5.1.23">>  [[Filter Step]]s support multiple parameters which are separated by a `,` character.