diff --git a/docs/reference/esql/functions/description/categorize.asciidoc b/docs/reference/esql/functions/description/categorize.asciidoc
new file mode 100644
index 0000000000000..b6574c1855505
--- /dev/null
+++ b/docs/reference/esql/functions/description/categorize.asciidoc
@@ -0,0 +1,5 @@
+// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
+
+*Description*
+
+Categorizes text messages.
diff --git a/docs/reference/esql/functions/kibana/definition/categorize.json b/docs/reference/esql/functions/kibana/definition/categorize.json
new file mode 100644
index 0000000000000..366475ed9d975
--- /dev/null
+++ b/docs/reference/esql/functions/kibana/definition/categorize.json
@@ -0,0 +1,33 @@
+{
+  "comment" : "This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.",
+  "type" : "eval",
+  "name" : "categorize",
+  "description" : "Categorizes text messages.",
+  "signatures" : [
+    {
+      "params" : [
+        {
+          "name" : "field",
+          "type" : "keyword",
+          "optional" : false,
+          "description" : "Expression to categorize"
+        }
+      ],
+      "variadic" : false,
+      "returnType" : "integer"
+    },
+    {
+      "params" : [
+        {
+          "name" : "field",
+          "type" : "text",
+          "optional" : false,
+          "description" : "Expression to categorize"
+        }
+      ],
+      "variadic" : false,
+      "returnType" : "integer"
+    }
+  ],
+  "preview" : false
+}
diff --git a/docs/reference/esql/functions/kibana/docs/categorize.md b/docs/reference/esql/functions/kibana/docs/categorize.md
new file mode 100644
index 0000000000000..f59151b5bee65
--- /dev/null
+++ b/docs/reference/esql/functions/kibana/docs/categorize.md
@@ -0,0 +1,7 @@
+<!--
+This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
+-->
+
+### CATEGORIZE
+Categorizes text messages.
+
diff --git a/docs/reference/esql/functions/layout/categorize.asciidoc b/docs/reference/esql/functions/layout/categorize.asciidoc
new file mode 100644
index 0000000000000..c547362b71ab0
--- /dev/null
+++ b/docs/reference/esql/functions/layout/categorize.asciidoc
@@ -0,0 +1,14 @@
+// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
+
+[discrete]
+[[esql-categorize]]
+=== `CATEGORIZE`
+
+*Syntax*
+
+[.text-center]
+image::esql/functions/signature/categorize.svg[Embedded,opts=inline]
+
+include::../parameters/categorize.asciidoc[]
+include::../description/categorize.asciidoc[]
+include::../types/categorize.asciidoc[]
diff --git a/docs/reference/esql/functions/parameters/categorize.asciidoc b/docs/reference/esql/functions/parameters/categorize.asciidoc
new file mode 100644
index 0000000000000..42629ebfc7d9f
--- /dev/null
+++ b/docs/reference/esql/functions/parameters/categorize.asciidoc
@@ -0,0 +1,6 @@
+// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
+
+*Parameters*
+
+`field`::
+Expression to categorize
diff --git a/docs/reference/esql/functions/signature/categorize.svg b/docs/reference/esql/functions/signature/categorize.svg
new file mode 100644
index 0000000000000..3f36f10382840
--- /dev/null
+++ b/docs/reference/esql/functions/signature/categorize.svg
@@ -0,0 +1 @@
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" width="324" height="46" viewbox="0 0 324 46"><defs><style type="text/css">#guide .c{fill:none;stroke:#222222;}#guide .k{fill:#000000;font-family:Roboto Mono,Sans-serif;font-size:20px;}#guide .s{fill:#e4f4ff;stroke:#222222;}#guide .syn{fill:#8D8D8D;font-family:Roboto Mono,Sans-serif;font-size:20px;}</style></defs><path class="c" d="M0 31h5m140 0h10m32 0h10m80 0h10m32 0h5"/><rect class="s" x="5" y="5" width="140" height="36"/><text class="k" x="15" y="31">CATEGORIZE</text><rect class="s" x="155" y="5" width="32" height="36" rx="7"/><text class="syn" x="165" y="31">(</text><rect class="s" x="197" y="5" width="80" height="36" rx="7"/><text class="k" x="207" y="31">field</text><rect class="s" x="287" y="5" width="32" height="36" rx="7"/><text class="syn" x="297" y="31">)</text></svg>
diff --git a/docs/reference/esql/functions/types/categorize.asciidoc b/docs/reference/esql/functions/types/categorize.asciidoc
new file mode 100644
index 0000000000000..4917ed313e6d7
--- /dev/null
+++ b/docs/reference/esql/functions/types/categorize.asciidoc
@@ -0,0 +1,10 @@
+// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.
+
+*Supported types*
+
+[%header.monospaced.styled,format=dsv,separator=|]
+|===
+field | result
+keyword | integer
+text | integer
+|===
diff --git a/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/grouping/Categorize.java b/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/grouping/Categorize.java
index 82c836a6f9d49..0865e070aecd4 100644
--- a/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/grouping/Categorize.java
+++ b/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/grouping/Categorize.java
@@ -63,7 +63,7 @@ public class Categorize extends GroupingFunction implements Validatable {
 
     private final Expression field;
 
-    @FunctionInfo(returnType = { "integer" }, description = "Categorizes text messages")
+    @FunctionInfo(returnType = { "integer" }, description = "Categorizes text messages.")
     public Categorize(
         Source source,
         @Param(name = "field", type = { "text", "keyword" }, description = "Expression to categorize") Expression field
diff --git a/x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/AbstractFunctionTestCase.java b/x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/AbstractFunctionTestCase.java
index c9a74c448644e..9f54b46acb514 100644
--- a/x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/AbstractFunctionTestCase.java
+++ b/x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/AbstractFunctionTestCase.java
@@ -1194,7 +1194,7 @@ protected static String functionName() {
     }
 
     private static FunctionDefinition definition(String name) {
-        EsqlFunctionRegistry registry = new EsqlFunctionRegistry();
+        EsqlFunctionRegistry registry = new EsqlFunctionRegistry().snapshotRegistry();
         if (registry.functionExists(name)) {
             return registry.resolveFunction(name);
         }