diff --git a/apps/api/src/chat/entities/contact.ts b/apps/api/src/chat/entities/contact.ts
index 045458e..ffed9b8 100644
--- a/apps/api/src/chat/entities/contact.ts
+++ b/apps/api/src/chat/entities/contact.ts
@@ -31,6 +31,7 @@ export class Contact extends BaseEntity {
   @prop({ default: [], index: true })
   tags: string[]
 
+  @Field(() => GraphQLJSONObject, { nullable: true })
   @jsonProp()
   fields?: Record<string, any>
 }
diff --git a/apps/runner/src/utils/input.utils.ts b/apps/runner/src/utils/input.utils.ts
index 117968f..346cde7 100644
--- a/apps/runner/src/utils/input.utils.ts
+++ b/apps/runner/src/utils/input.utils.ts
@@ -51,6 +51,13 @@ export function parseInput(input: unknown, outputs: Record<string, Record<string
   return input
 }
 
+// Your custom handler for undefined functions
+const customFunctionHandler = (name, args) => {
+  console.log(`Unknown function ${name} called with arguments:`, args)
+  // You can return whatever you like here or throw an error
+  return null
+}
+
 /**
  * Replace references with their values and calculate expression
  * Example:
@@ -60,7 +67,7 @@ export function parseInput(input: unknown, outputs: Record<string, Record<string
  */
 export function calculateExpression(input: string, references: Record<string, Record<string, unknown>>): unknown {
   // each "[\w[\]]" group matches the allowed characters for variables, including array access (e.g. a.b[0].c)
-  const operatorsRegex = /[\w\s[\]]+(\.[\w\s[\]]+|\[\d+\])*/g
+  const operatorsRegex = /(\w+\[\w+\]|\w+)\.[\w\[\]]+(\.[\w\[\]]+)*/g
 
   const operators = [...input.matchAll(operatorsRegex)]
 
@@ -100,6 +107,11 @@ export function calculateExpression(input: string, references: Record<string, Re
     }
     return ('' + str).substring(start, end)
   })
+  parser.set('contact', (str: string, params: string) => {
+    console.log(`get: ${str}`, params)
+    console.log(`references:`, references)
+    return _.get(references, `${str}[${params}]`)
+  })
   parser.set('formatNumber', (value: number, locales?: Intl.LocalesArgument) => Number(value).toLocaleString(locales))
   parser.set('lowercase', (str: string) => (str ? ('' + str).toLowerCase() : str))
   parser.set('uppercase', (str: string) => (str ? ('' + str).toUpperCase() : str))
@@ -181,3 +193,7 @@ export function findOutputKeys(input: Record<string, any>, key: string): string[
 
   return matches
 }
+
+export function strToInterpolationKey(str: string): string {
+  return str.replace(/[^a-zA-Z0-9]/g, '_')
+}
diff --git a/generated/graphql.ts b/generated/graphql.ts
index 3242c48..0620845 100644
--- a/generated/graphql.ts
+++ b/generated/graphql.ts
@@ -1060,6 +1060,7 @@ export interface Contact {
     createdAt: DateTime;
     address: string;
     tags?: Nullable<string[]>;
+    fields?: Nullable<JSONObject>;
 }
 
 export interface AccountCredential {
@@ -1372,6 +1373,7 @@ export interface ContactDeleteResponse {
     createdAt?: Nullable<DateTime>;
     address?: Nullable<string>;
     tags?: Nullable<string[]>;
+    fields?: Nullable<JSONObject>;
 }
 
 export interface ContactEdge {
diff --git a/generated/schema.graphql b/generated/schema.graphql
index 04836b1..fab6cfd 100644
--- a/generated/schema.graphql
+++ b/generated/schema.graphql
@@ -413,6 +413,7 @@ type Contact {
   createdAt: DateTime!
   address: String!
   tags: [String!]
+  fields: JSONObject
 }
 
 type AccountCredential {
@@ -826,6 +827,7 @@ type ContactDeleteResponse {
   createdAt: DateTime
   address: String
   tags: [String!]
+  fields: JSONObject
 }
 
 type ContactEdge {