diff --git a/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts b/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts
index dcaa898b15a5d..7af0871fd59ef 100644
--- a/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/autocomplete/autocomplete.test.ts
@@ -1104,7 +1104,7 @@ describe('autocomplete', () => {
       ...getFieldNamesByType('string').map((v) => `${v},`),
       ...getFunctionSignaturesByReturnType('eval', 'string', { evalMath: true }, undefined, [
         'concat',
-      ]).map((v) => `${v},`),
+      ]).map((v) => ({ ...v, text: `${v.text},` })),
     ]);
     testSuggestions('from a | eval a=concat(stringField, ', [
       ...getFieldNamesByType('string'),
@@ -1124,7 +1124,7 @@ describe('autocomplete', () => {
       ...getFieldNamesByType('ip').map((v) => `${v},`),
       ...getFunctionSignaturesByReturnType('eval', 'ip', { evalMath: true }, undefined, [
         'cidr_match',
-      ]).map((v) => `${v},`),
+      ]).map((v) => ({ ...v, text: `${v.text},` })),
     ]);
     testSuggestions('from a | eval a=cidr_match(ipField, ', [
       ...getFieldNamesByType('string'),
@@ -1289,7 +1289,7 @@ describe('autocomplete', () => {
           ...getLiteralsByType('time_literal').map((t) => `${t},`),
           ...getFunctionSignaturesByReturnType('eval', 'date', { evalMath: true }, undefined, [
             'date_trunc',
-          ]).map((t) => `${t},`),
+          ]).map((t) => ({ ...t, text: `${t.text},` })),
           ...getFieldNamesByType('date').map((t) => `${t},`),
         ],
         '('
diff --git a/packages/kbn-esql-validation-autocomplete/src/autocomplete/factories.ts b/packages/kbn-esql-validation-autocomplete/src/autocomplete/factories.ts
index ad49303c55def..5820118d0013a 100644
--- a/packages/kbn-esql-validation-autocomplete/src/autocomplete/factories.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/autocomplete/factories.ts
@@ -46,7 +46,7 @@ function getSafeInsertSourceText(text: string) {
 }
 
 export function getSuggestionFunctionDefinition(fn: FunctionDefinition): SuggestionRawDefinition {
-  const fullSignatures = getFunctionSignatures(fn);
+  const fullSignatures = getFunctionSignatures(fn, { capitalize: true, withTypes: true });
   return {
     label: fullSignatures[0].declaration,
     text: `${fn.name.toUpperCase()}($0)`,
@@ -66,7 +66,7 @@ export function getSuggestionFunctionDefinition(fn: FunctionDefinition): Suggest
 export function getSuggestionBuiltinDefinition(fn: FunctionDefinition): SuggestionRawDefinition {
   const hasArgs = fn.signatures.some(({ params }) => params.length > 1);
   return {
-    label: fn.name,
+    label: fn.name.toUpperCase(),
     text: hasArgs ? `${fn.name.toUpperCase()} $0` : fn.name.toUpperCase(),
     asSnippet: hasArgs,
     kind: 'Operator',
diff --git a/packages/kbn-esql-validation-autocomplete/src/definitions/helpers.ts b/packages/kbn-esql-validation-autocomplete/src/definitions/helpers.ts
index 0ccb7855b284b..a44db712ab230 100644
--- a/packages/kbn-esql-validation-autocomplete/src/definitions/helpers.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/definitions/helpers.ts
@@ -17,7 +17,10 @@ import type { CommandDefinition, FunctionDefinition } from './types';
  */
 export function getFunctionSignatures(
   { name, signatures }: FunctionDefinition,
-  { withTypes }: { withTypes: boolean } = { withTypes: true }
+  { withTypes, capitalize }: { withTypes: boolean; capitalize?: boolean } = {
+    withTypes: true,
+    capitalize: false,
+  }
 ) {
   return signatures.map(({ params, returnType, minParams }) => {
     // for functions with a minimum number of args, repeat the last arg multiple times
@@ -25,7 +28,7 @@ export function getFunctionSignatures(
     const minParamsToAdd = Math.max((minParams || 0) - params.length, 0);
     const extraArg = Array(minParamsToAdd || 1).fill(params[Math.max(params.length - 1, 0)]);
     return {
-      declaration: `${name}(${params
+      declaration: `${capitalize ? name.toUpperCase() : name}(${params
         .map((arg) => printArguments(arg, withTypes))
         .join(', ')}${handleAdditionalArgs(minParamsToAdd > 0, extraArg, withTypes)})${
         withTypes ? `: ${returnType}` : ''
diff --git a/packages/kbn-esql-validation-autocomplete/src/shared/helpers.ts b/packages/kbn-esql-validation-autocomplete/src/shared/helpers.ts
index 94aae4194d367..6cedf378c35aa 100644
--- a/packages/kbn-esql-validation-autocomplete/src/shared/helpers.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/shared/helpers.ts
@@ -290,13 +290,12 @@ export function areFieldAndVariableTypesCompatible(
   return fieldType === variableType;
 }
 
-export function printFunctionSignature(arg: ESQLFunction, useCaps = true): string {
+export function printFunctionSignature(arg: ESQLFunction): string {
   const fnDef = getFunctionDefinition(arg.name);
   if (fnDef) {
     const signature = getFunctionSignatures(
       {
         ...fnDef,
-        name: useCaps ? fnDef.name.toUpperCase() : fnDef.name,
         signatures: [
           {
             ...fnDef?.signatures[0],
@@ -313,7 +312,7 @@ export function printFunctionSignature(arg: ESQLFunction, useCaps = true): strin
           },
         ],
       },
-      { withTypes: false }
+      { withTypes: false, capitalize: true }
     );
     return signature[0].declaration;
   }
diff --git a/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json b/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json
index c49f5c7af82df..98bcf3468348e 100644
--- a/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json
+++ b/packages/kbn-esql-validation-autocomplete/src/validation/esql_validation_meta_tests.json
@@ -9187,8 +9187,8 @@
     {
       "query": "from a_index | eval date_diff(\"year\", concat(\"20\", \"22\"), concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [date_diff] must be [date], found value [concat(\"20\", \"22\")] type [string]",
-        "Argument of [date_diff] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [date_diff] must be [date], found value [concat(\"20\",\"22\")] type [string]",
+        "Argument of [date_diff] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -11080,7 +11080,7 @@
     {
       "query": "from a_index | eval date_extract(\"ALIGNED_DAY_OF_WEEK_IN_MONTH\", concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [date_extract] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [date_extract] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -11167,7 +11167,7 @@
     {
       "query": "from a_index | eval date_format(stringField, concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [date_format] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [date_format] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -11384,7 +11384,7 @@
     {
       "query": "from a_index | eval date_trunc(1 year, concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [date_trunc] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [date_trunc] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -11396,8 +11396,8 @@
     {
       "query": "from a_index | eval date_trunc(concat(\"20\", \"22\"), concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [date_trunc] must be [time_literal], found value [concat(\"20\", \"22\")] type [string]",
-        "Argument of [date_trunc] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [date_trunc] must be [time_literal], found value [concat(\"20\",\"22\")] type [string]",
+        "Argument of [date_trunc] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -24139,7 +24139,7 @@
     {
       "query": "from a_index | stats max(concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [max] must be [number], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [max] must be [number], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -24412,7 +24412,7 @@
     {
       "query": "from a_index | stats min(concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [min] must be [number], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [min] must be [number], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -24970,14 +24970,14 @@
     {
       "query": "from a_index | stats bucket(concat(\"20\", \"22\"), 1 year)",
       "error": [
-        "Argument of [bucket] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [bucket] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
     {
       "query": "from a_index | stats by bucket(concat(\"20\", \"22\"), 1 year)",
       "error": [
-        "Argument of [bucket] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [bucket] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -24989,7 +24989,7 @@
     {
       "query": "from a_index | stats bucket(concat(\"20\", \"22\"), 5, \"a\", \"a\")",
       "error": [
-        "Argument of [bucket] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [bucket] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -25001,7 +25001,7 @@
     {
       "query": "from a_index | stats bucket(concat(\"20\", \"22\"), 5, concat(\"20\", \"22\"), concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [bucket] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [bucket] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -25013,7 +25013,7 @@
     {
       "query": "from a_index | stats bucket(concat(\"20\", \"22\"), 5, \"a\", concat(\"20\", \"22\"))",
       "error": [
-        "Argument of [bucket] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [bucket] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -25025,7 +25025,7 @@
     {
       "query": "from a_index | stats bucket(concat(\"20\", \"22\"), 5, concat(\"20\", \"22\"), \"a\")",
       "error": [
-        "Argument of [bucket] must be [date], found value [concat(\"20\", \"22\")] type [string]"
+        "Argument of [bucket] must be [date], found value [concat(\"20\",\"22\")] type [string]"
       ],
       "warning": []
     },
@@ -26368,6 +26368,91 @@
       "error": [],
       "warning": []
     },
+    {
+      "query": "row var = exp(5)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "row exp(5)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "row var = exp(to_integer(true))",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "row var = exp(true)",
+      "error": [
+        "Argument of [exp] must be [number], found value [true] type [boolean]"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | where exp(numberField) > 0",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | where exp(booleanField) > 0",
+      "error": [
+        "Argument of [exp] must be [number], found value [booleanField] type [boolean]"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | eval var = exp(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | eval exp(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | eval var = exp(to_integer(booleanField))",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | eval exp(booleanField)",
+      "error": [
+        "Argument of [exp] must be [number], found value [booleanField] type [boolean]"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | eval var = exp(*)",
+      "error": [
+        "Using wildcards (*) in exp is not allowed"
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | eval exp(numberField, extraArg)",
+      "error": [
+        "Error: [exp] function expects exactly one argument, got 2."
+      ],
+      "warning": []
+    },
+    {
+      "query": "from a_index | sort exp(numberField)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "from a_index | eval exp(null)",
+      "error": [],
+      "warning": []
+    },
+    {
+      "query": "row nullVar = null | eval exp(nullVar)",
+      "error": [],
+      "warning": []
+    },
     {
       "query": "f",
       "error": [
diff --git a/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts b/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts
index 14d9c50d5c88c..7421621fd941d 100644
--- a/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/validation/validation.test.ts
@@ -103,7 +103,7 @@ function prepareNestedFunction(fnSignature: FunctionDefinition): string {
         },
       ],
     },
-    { withTypes: false }
+    { withTypes: false, capitalize: false }
   )[0].declaration;
 }
 function getFieldMapping(
@@ -1784,8 +1784,8 @@ describe('validation logic', () => {
         testErrorsAndWarnings(
           'from a_index | eval date_diff("year", concat("20", "22"), concat("20", "22"))',
           [
-            'Argument of [date_diff] must be [date], found value [concat("20", "22")] type [string]',
-            'Argument of [date_diff] must be [date], found value [concat("20", "22")] type [string]',
+            'Argument of [date_diff] must be [date], found value [concat("20","22")] type [string]',
+            'Argument of [date_diff] must be [date], found value [concat("20","22")] type [string]',
           ]
         );
       });
@@ -2666,7 +2666,7 @@ describe('validation logic', () => {
         testErrorsAndWarnings(
           'from a_index | eval date_extract("ALIGNED_DAY_OF_WEEK_IN_MONTH", concat("20", "22"))',
           [
-            'Argument of [date_extract] must be [date], found value [concat("20", "22")] type [string]',
+            'Argument of [date_extract] must be [date], found value [concat("20","22")] type [string]',
           ]
         );
       });
@@ -2710,7 +2710,7 @@ describe('validation logic', () => {
         testErrorsAndWarnings('row nullVar = null | eval date_format(nullVar, nullVar)', []);
         testErrorsAndWarnings('from a_index | eval date_format(stringField, "2022")', []);
         testErrorsAndWarnings('from a_index | eval date_format(stringField, concat("20", "22"))', [
-          'Argument of [date_format] must be [date], found value [concat("20", "22")] type [string]',
+          'Argument of [date_format] must be [date], found value [concat("20","22")] type [string]',
         ]);
       });
 
@@ -2815,15 +2815,15 @@ describe('validation logic', () => {
         testErrorsAndWarnings('row nullVar = null | eval date_trunc(nullVar, nullVar)', []);
         testErrorsAndWarnings('from a_index | eval date_trunc(1 year, "2022")', []);
         testErrorsAndWarnings('from a_index | eval date_trunc(1 year, concat("20", "22"))', [
-          'Argument of [date_trunc] must be [date], found value [concat("20", "22")] type [string]',
+          'Argument of [date_trunc] must be [date], found value [concat("20","22")] type [string]',
         ]);
         testErrorsAndWarnings('from a_index | eval date_trunc("2022", "2022")', []);
 
         testErrorsAndWarnings(
           'from a_index | eval date_trunc(concat("20", "22"), concat("20", "22"))',
           [
-            'Argument of [date_trunc] must be [time_literal], found value [concat("20", "22")] type [string]',
-            'Argument of [date_trunc] must be [date], found value [concat("20", "22")] type [string]',
+            'Argument of [date_trunc] must be [time_literal], found value [concat("20","22")] type [string]',
+            'Argument of [date_trunc] must be [date], found value [concat("20","22")] type [string]',
           ]
         );
       });
@@ -9170,7 +9170,7 @@ describe('validation logic', () => {
         testErrorsAndWarnings('row nullVar = null | stats max(nullVar)', []);
         testErrorsAndWarnings('from a_index | stats max("2022")', []);
         testErrorsAndWarnings('from a_index | stats max(concat("20", "22"))', [
-          'Argument of [max] must be [number], found value [concat("20", "22")] type [string]',
+          'Argument of [max] must be [number], found value [concat("20","22")] type [string]',
         ]);
       });
 
@@ -9314,7 +9314,7 @@ describe('validation logic', () => {
         testErrorsAndWarnings('row nullVar = null | stats min(nullVar)', []);
         testErrorsAndWarnings('from a_index | stats min("2022")', []);
         testErrorsAndWarnings('from a_index | stats min(concat("20", "22"))', [
-          'Argument of [min] must be [number], found value [concat("20", "22")] type [string]',
+          'Argument of [min] must be [number], found value [concat("20","22")] type [string]',
         ]);
       });
 
@@ -9632,34 +9632,34 @@ describe('validation logic', () => {
         );
         testErrorsAndWarnings('from a_index | stats bucket("2022", 1 year)', []);
         testErrorsAndWarnings('from a_index | stats bucket(concat("20", "22"), 1 year)', [
-          'Argument of [bucket] must be [date], found value [concat("20", "22")] type [string]',
+          'Argument of [bucket] must be [date], found value [concat("20","22")] type [string]',
         ]);
         testErrorsAndWarnings('from a_index | stats by bucket(concat("20", "22"), 1 year)', [
-          'Argument of [bucket] must be [date], found value [concat("20", "22")] type [string]',
+          'Argument of [bucket] must be [date], found value [concat("20","22")] type [string]',
         ]);
         testErrorsAndWarnings('from a_index | stats bucket("2022", 5, "a", "a")', []);
         testErrorsAndWarnings('from a_index | stats bucket(concat("20", "22"), 5, "a", "a")', [
-          'Argument of [bucket] must be [date], found value [concat("20", "22")] type [string]',
+          'Argument of [bucket] must be [date], found value [concat("20","22")] type [string]',
         ]);
         testErrorsAndWarnings('from a_index | stats bucket("2022", 5, "2022", "2022")', []);
 
         testErrorsAndWarnings(
           'from a_index | stats bucket(concat("20", "22"), 5, concat("20", "22"), concat("20", "22"))',
-          ['Argument of [bucket] must be [date], found value [concat("20", "22")] type [string]']
+          ['Argument of [bucket] must be [date], found value [concat("20","22")] type [string]']
         );
 
         testErrorsAndWarnings('from a_index | stats bucket("2022", 5, "a", "2022")', []);
 
         testErrorsAndWarnings(
           'from a_index | stats bucket(concat("20", "22"), 5, "a", concat("20", "22"))',
-          ['Argument of [bucket] must be [date], found value [concat("20", "22")] type [string]']
+          ['Argument of [bucket] must be [date], found value [concat("20","22")] type [string]']
         );
 
         testErrorsAndWarnings('from a_index | stats bucket("2022", 5, "2022", "a")', []);
 
         testErrorsAndWarnings(
           'from a_index | stats bucket(concat("20", "22"), 5, concat("20", "22"), "a")',
-          ['Argument of [bucket] must be [date], found value [concat("20", "22")] type [string]']
+          ['Argument of [bucket] must be [date], found value [concat("20","22")] type [string]']
         );
       });
 
diff --git a/packages/kbn-esql-validation-autocomplete/src/validation/validation.ts b/packages/kbn-esql-validation-autocomplete/src/validation/validation.ts
index e3c94aee3f482..cea9dccbd8d97 100644
--- a/packages/kbn-esql-validation-autocomplete/src/validation/validation.ts
+++ b/packages/kbn-esql-validation-autocomplete/src/validation/validation.ts
@@ -43,7 +43,6 @@ import {
   isSupportedFunction,
   isTimeIntervalItem,
   inKnownTimeInterval,
-  printFunctionSignature,
   sourceExists,
   getColumnExists,
   hasWildcard,
@@ -220,7 +219,7 @@ function validateNestedFunctionArg(
           values: {
             name: astFunction.name,
             argType: parameterDefinition.type,
-            value: printFunctionSignature(actualArg, false) || actualArg.name,
+            value: actualArg.text,
             givenType: argFn.signatures[0].returnType,
           },
           locations: actualArg.location,