diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.scss b/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.scss
index 3bb2759274..8bc422eed1 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.scss
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.scss
@@ -36,14 +36,20 @@
 .tb-js-func {
   .ace_tb {
     &.ace_calculated-field {
-      &-key {
+      &-ctx {
         color: #C52F00;
       }
-      &-ts, &-time-window, &-values, &-value, &-func {
+      &-args {
+        color: #185F2A;
+      }
+      &-key {
+        color: #c24c1a;
+      }
+      &-time-window, &-values, &-func, &-value, &-ts {
         color: #7214D0;
       }
-      &-start-ts, &-end-ts, &-limit {
-        color: #185F2A;
+      &-start-ts, &-end-ts {
+        color: #2CAA00;
       }
     }
   }
diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.ts b/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.ts
index 0c3e7464cd..052b660c3c 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.ts
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/dialog/calculated-field-dialog.component.ts
@@ -70,7 +70,7 @@ export class CalculatedFieldDialogComponent extends DialogComponent<CalculatedFi
   functionArgs$ = this.configFormGroup.get('arguments').valueChanges
     .pipe(
       startWith(this.data.value?.configuration?.arguments ?? {}),
-      map(argumentsObj => Object.keys(argumentsObj))
+      map(argumentsObj => ['ctx', ...Object.keys(argumentsObj)])
     );
 
   argumentsEditorCompleter$ = this.configFormGroup.get('arguments').valueChanges
diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.html b/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.html
index 566a433545..4d7f20d6d5 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.html
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.html
@@ -55,6 +55,14 @@
                       class="tb-error">
               warning
             </mat-icon>
+          } @else if (argumentFormGroup.get('argumentName').touched && argumentFormGroup.get('argumentName').hasError('equalCtx')) {
+            <mat-icon matSuffix
+                      matTooltipPosition="above"
+                      matTooltipClass="tb-error-tooltip"
+                      [matTooltip]="'calculated-fields.hint.argument-name-ctx' | translate"
+                      class="tb-error">
+              warning
+            </mat-icon>
           }
         </mat-form-field>
       </div>
diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.ts b/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.ts
index 7e41f60968..482851c59c 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.ts
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/panel/calculated-field-argument-panel.component.ts
@@ -64,7 +64,7 @@ export class CalculatedFieldArgumentPanelComponent implements OnInit {
   readonly defaultLimit = Math.floor(this.maxDataPointsPerRollingArg / 10);
 
   argumentFormGroup = this.fb.group({
-    argumentName: ['', [Validators.required, this.uniqNameRequired(), Validators.pattern(charsWithNumRegex), Validators.maxLength(255)]],
+    argumentName: ['', [Validators.required, this.uniqNameRequired(), this.notEqualCtxValidator(), Validators.pattern(charsWithNumRegex), Validators.maxLength(255)]],
     refEntityId: this.fb.group({
       entityType: [ArgumentEntityType.Current],
       id: ['']
@@ -237,6 +237,13 @@ export class CalculatedFieldArgumentPanelComponent implements OnInit {
     }
   }
 
+  private notEqualCtxValidator(): ValidatorFn {
+    return (control: FormControl) => {
+      const trimmedValue = control.value.trim().toLowerCase();
+      return trimmedValue === 'ctx' ? { equalCtx: true } : null;
+    };
+  }
+
   private observeUpdatePosition(): void {
     merge(
       this.refEntityIdFormGroup.get('entityType').valueChanges,
diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.html b/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.html
index cda99f6c09..6859ff6dab 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.html
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.html
@@ -15,7 +15,7 @@
     limitations under the License.
 
 -->
-<form #testScriptContainer class="test-dialog-container size-full" [formGroup]="calculatedFieldScriptTestFormGroup">
+<form #testScriptContainer class="cf-test-dialog-container size-full" [formGroup]="calculatedFieldScriptTestFormGroup">
   <mat-toolbar class="flex justify-between" color="primary">
     <h2>{{ 'calculated-fields.test-script-function' | translate }} ({{ 'api-usage.tbel' | translate }})</h2>
     <button mat-icon-button
diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.scss b/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.scss
index d944e2a683..94766e944a 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.scss
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.scss
@@ -13,62 +13,79 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-:host {
-  .test-dialog-container {
-    .block-label {
-      padding: 4px;
-      color: #00acc1;
-      background: rgba(220, 220, 220, .35);
-      border-radius: 5px;
-    }
 
-    .test-block-content {
-      padding-top: 5px;
-      padding-left: 5px;
-      border: 1px solid #c0c0c0;
-      overflow: scroll;
-    }
+.cf-test-dialog-container {
+  .gutter {
+    background-color: #eee;
+    background-repeat: no-repeat;
+    background-position: 50%;
+  }
 
-    .block-label-container {
-      position: absolute;
-      z-index: 10;
-      font-size: 12px;
-      font-weight: bold;
+  .gutter.gutter-horizontal {
+    cursor: col-resize;
+    background-image: url("../../../../../../../assets/split.js/grips/horizontal.png");
+  }
 
-      &.left {
-        right: 112px;
-        top: 9px;
-      }
+  .gutter.gutter-vertical {
+    cursor: row-resize;
+    background-image: url("../../../../../../../assets/split.js/grips/vertical.png");
+  }
 
-      &.right-bottom {
-        right: 40px;
-        top: 6px;
-      }
+  .block-label {
+    padding: 4px;
+    color: #00acc1;
+    background: rgba(220, 220, 220, .35);
+    border-radius: 5px;
+  }
 
-      &.right-top {
-        right: 8px;
-        top: 2px;
-      }
-    }
+  .test-block-content {
+    padding-top: 5px;
+    padding-left: 5px;
+    border: 1px solid #c0c0c0;
+    overflow: scroll;
   }
-}
 
-:host::ng-deep {
-  .test-dialog-container {
-    .gutter {
-      background-color: #eee;
-      background-repeat: no-repeat;
-      background-position: 50%;
+  .block-label-container {
+    position: absolute;
+    z-index: 10;
+    font-size: 12px;
+    font-weight: bold;
+
+    &.left {
+      right: 112px;
+      top: 9px;
+    }
+
+    &.right-bottom {
+      right: 40px;
+      top: 6px;
     }
 
-    .gutter.gutter-horizontal {
-      cursor: col-resize;
-      background-image: url("../../../../../../../assets/split.js/grips/horizontal.png");
+    &.right-top {
+      right: 8px;
+      top: 2px;
     }
+  }
+}
 
-    .gutter.gutter-vertical {
-      cursor: row-resize;
-      background-image: url("../../../../../../../assets/split.js/grips/vertical.png");
+.tb-js-func {
+  .ace_tb {
+    &.ace_calculated-field {
+      &-ctx {
+        color: #C52F00;
+      }
+      &-args {
+        color: #185F2A;
+      }
+      &-key {
+        color: #c24c1a;
+      }
+      &-time-window, &-values, &-func, &-value, &-ts {
+        color: #7214D0;
+      }
+      &-start-ts, &-end-ts {
+        color: #2CAA00;
+      }
     }
   }
 }
diff --git a/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.ts b/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.ts
index 78c3b17bcb..4e15e4a240 100644
--- a/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.ts
+++ b/ui-ngx/src/app/modules/home/components/calculated-fields/components/test-dialog/calculated-field-script-test-dialog.component.ts
@@ -22,6 +22,7 @@ import {
   Inject,
   OnDestroy,
   ViewChild,
+  ViewEncapsulation,
 } from '@angular/core';
 import { MAT_DIALOG_DATA, MatDialog, MatDialogRef } from '@angular/material/dialog';
 import { Store } from '@ngrx/store';
@@ -49,6 +50,7 @@ import {
   selector: 'tb-calculated-field-script-test-dialog',
   templateUrl: './calculated-field-script-test-dialog.component.html',
   styleUrls: ['./calculated-field-script-test-dialog.component.scss'],
+  encapsulation: ViewEncapsulation.None
 })
 export class CalculatedFieldScriptTestDialogComponent extends DialogComponent<CalculatedFieldScriptTestDialogComponent,
   string> implements AfterViewInit, OnDestroy {
@@ -70,7 +72,7 @@ export class CalculatedFieldScriptTestDialogComponent extends DialogComponent<Ca
 
   readonly ContentType = ContentType;
   readonly ScriptLanguage = ScriptLanguage;
-  readonly functionArgs = Object.keys(this.data.arguments);
+  readonly functionArgs = ['ctx', ...Object.keys(this.data.arguments)];
 
   private testScriptResize: ResizeObserver;
   private splitObjects: SplitObject[] = [];
diff --git a/ui-ngx/src/app/shared/models/calculated-field.models.ts b/ui-ngx/src/app/shared/models/calculated-field.models.ts
index 7083ce7ae0..c898342c68 100644
--- a/ui-ngx/src/app/shared/models/calculated-field.models.ts
+++ b/ui-ngx/src/app/shared/models/calculated-field.models.ts
@@ -225,7 +225,7 @@ export interface CalculatedFieldLatestTelemetryArgumentValue<ValueType = unknown
 }
 
 export interface CalculatedFieldRollingTelemetryArgumentValue<ValueType = unknown> extends CalculatedFieldArgumentValueBase {
-  timeWindow: { startTs: number; endTs: number; limit: number };
+  timeWindow: { startTs: number; endTs: number; };
   values: CalculatedFieldSingleArgumentValue<ValueType>[];
 }
 
@@ -235,10 +235,10 @@ export type CalculatedFieldArgumentEventValue<ValueType = unknown> = CalculatedF
 
 export type CalculatedFieldEventArguments<ValueType = unknown> = Record<string, CalculatedFieldArgumentEventValue<ValueType>>;
 
-export const CalculatedFieldLatestTelemetryArgumentAutocomplete = {
+export const CalculatedFieldCtxLatestTelemetryArgumentAutocomplete = {
   meta: 'object',
   type: '{ ts: number; value: any; }',
-  description: 'Calculated field latest telemetry value argument.',
+  description: 'Calculated field context latest telemetry value argument.',
   children: {
     ts: {
       meta: 'number',
@@ -253,10 +253,10 @@ export const CalculatedFieldLatestTelemetryArgumentAutocomplete = {
   },
 };
 
-export const CalculatedFieldAttributeValueArgumentAutocomplete = {
+export const CalculatedFieldCtxAttributeValueArgumentAutocomplete = {
   meta: 'object',
   type: '{ ts: number; value: any; }',
-  description: 'Calculated field attribute value argument.',
+  description: 'Calculated field context attribute value argument.',
   children: {
     ts: {
       meta: 'number',
@@ -270,6 +270,19 @@ export const CalculatedFieldAttributeValueArgumentAutocomplete = {
     }
   },
 };
+
+export const CalculatedFieldLatestTelemetryArgumentAutocomplete = {
+  meta: 'any',
+  type: 'any',
+  description: 'Calculated field latest telemetry argument value.',
+};
+
+export const CalculatedFieldAttributeValueArgumentAutocomplete = {
+  meta: 'any',
+  type: 'any',
+  description: 'Calculated field attribute argument value.',
+};
+
 export const CalculatedFieldRollingValueArgumentFunctionsAutocomplete = {
   max: {
     meta: 'function',
@@ -513,35 +526,84 @@ export const getCalculatedFieldArgumentsEditorCompleter = (argumentsObj: Record<
     switch (argumentsObj[key].refEntityKey.type) {
       case ArgumentType.Attribute:
         acc[key] = CalculatedFieldAttributeValueArgumentAutocomplete;
+        acc.ctx.children.args.children[key] = CalculatedFieldCtxAttributeValueArgumentAutocomplete;
         break;
       case ArgumentType.LatestTelemetry:
         acc[key] = CalculatedFieldLatestTelemetryArgumentAutocomplete;
+        acc.ctx.children.args.children[key] = CalculatedFieldCtxLatestTelemetryArgumentAutocomplete;
         break;
       case ArgumentType.Rolling:
         acc[key] = CalculatedFieldRollingValueArgumentAutocomplete;
+        acc.ctx.children.args.children[key] = CalculatedFieldRollingValueArgumentAutocomplete;
         break;
     }
     return acc;
-  }, {}));
+  }, {
+    ctx: {
+      meta: 'object',
+      type: '{ args: { [key: string]: object } }',
+      description: 'Calculated field context.',
+      children: {
+        args: {
+          meta: 'object',
+          type: '{ [key: string]: object }',
+          description: 'Calculated field context arguments.',
+          children: {}
+        }
+      }
+    }
+  }));
 }
 
 export const getCalculatedFieldArgumentsHighlights = (
   argumentsObj: Record<string, CalculatedFieldArgument>
 ): AceHighlightRules => {
+  const calculatedFieldArgumentsKeys = Object.keys(argumentsObj).map(key => ({
+    token: 'tb.calculated-field-key',
+    regex: `\\b${key}\\b`,
+    next: argumentsObj[key].refEntityKey.type === ArgumentType.Rolling
+      ? 'calculatedFieldRollingArgumentValue'
+      : 'start'
+  }));
+  const calculatedFieldCtxArgumentsHighlightRules = {
+    calculatedFieldCtxArgs: [
+      dotOperatorHighlightRule,
+      ...calculatedFieldArgumentsKeys.map(argumentRule => argumentRule.next === 'start' ? {...argumentRule, next: 'calculatedFieldSingleArgumentValue' } : argumentRule),
+      endGroupHighlightRule
+    ]
+  };
+
   return {
-    start: Object.keys(argumentsObj).map(key => ({
-      token: 'tb.calculated-field-key',
-      regex: `\\b${key}\\b`,
-      next: argumentsObj[key].refEntityKey.type === ArgumentType.Rolling
-        ? 'calculatedFieldRollingArgumentValue'
-        : 'calculatedFieldSingleArgumentValue'
-    })),
+    start: [
+      calculatedFieldArgumentsContextHighlightRules,
+      ...calculatedFieldArgumentsKeys,
+    ],
+    ...calculatedFieldArgumentsContextValueHighlightRules,
+    ...calculatedFieldCtxArgumentsHighlightRules,
     ...calculatedFieldSingleArgumentValueHighlightRules,
     ...calculatedFieldRollingArgumentValueHighlightRules,
     ...calculatedFieldTimeWindowArgumentValueHighlightRules
   };
 };
 
+const calculatedFieldArgumentsContextHighlightRules: AceHighlightRule = {
+  token: 'tb.calculated-field-ctx',
+  regex: /ctx/,
+  next: 'calculatedFieldCtxValue'
+}
+
+const calculatedFieldArgumentsContextValueHighlightRules: AceHighlightRules = {
+  calculatedFieldCtxValue: [
+    dotOperatorHighlightRule,
+    {
+      token: 'tb.calculated-field-args',
+      regex: /args/,
+      next: 'calculatedFieldCtxArgs'
+    },
+    endGroupHighlightRule
+  ]
+}
+
 const calculatedFieldSingleArgumentValueHighlightRules: AceHighlightRules = {
   calculatedFieldSingleArgumentValue: [
     dotOperatorHighlightRule,
@@ -597,16 +659,11 @@ const calculatedFieldTimeWindowArgumentValueHighlightRules: AceHighlightRules =
       regex: /endTs/,
       next: 'no_regex'
     },
-    {
-      token: 'tb.calculated-field-limit',
-      regex: /limit/,
-      next: 'no_regex'
-    },
     endGroupHighlightRule
   ]
 }
 
 export const calculatedFieldDefaultScript = 'return {\n' +
   '    // Convert Fahrenheit to Celsius\n' +
-  '    "temperatureCelsius": (temperature.value - 32) / 1.8\n' +
+  '    "temperatureCelsius": (temperature - 32) / 1.8\n' +
   '};'
diff --git a/ui-ngx/src/assets/locale/locale.constant-en_US.json b/ui-ngx/src/assets/locale/locale.constant-en_US.json
index a26f267c64..84fdd4f011 100644
--- a/ui-ngx/src/assets/locale/locale.constant-en_US.json
+++ b/ui-ngx/src/assets/locale/locale.constant-en_US.json
@@ -1070,6 +1070,7 @@
             "argument-name-pattern": "Argument name is invalid.",
             "argument-name-duplicate": "Argument with such name already exists.",
             "argument-name-max-length": "Argument name should be less than 256 characters.",
+            "argument-name-ctx": "Argument name 'ctx' is reserved and cannot be used.",
             "argument-type-required": "Argument type is required.",
             "max-args": "Maximum number of arguments reached.",
             "decimals-range": "Decimals by default should be a number between 0 and 15.",