diff --git a/schemas/core/any-type.json b/schemas/core/any-type.json
index ed45cf4..fa02105 100644
--- a/schemas/core/any-type.json
+++ b/schemas/core/any-type.json
@@ -2,7 +2,7 @@
   "$id": "https://raw.githubusercontent.com/guardrails-ai/interfaces/core-schemas/schemas/core/any-type.json",
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "title": "AnyType",
-  "anyOf": [
+  "oneOf": [
     {
       "$ref": "#/$defs/primitives"
     },
@@ -15,7 +15,7 @@
   ],
   "$defs": {
     "primitives": {
-      "anyOf": [
+      "oneOf": [
         {
           "type": "boolean"
         },
@@ -40,7 +40,7 @@
     "arrays": {
       "type": "array",
       "items": {
-        "anyOf": [
+        "oneOf": [
           {
             "$ref": "#/$defs/primitives"
           },
diff --git a/schemas/core/call.json b/schemas/core/call.json
index b0cd3e4..04faeb4 100644
--- a/schemas/core/call.json
+++ b/schemas/core/call.json
@@ -16,7 +16,7 @@
       "default": {}
     },
     "exception": {
-      "anyOf": [
+      "oneOf": [
         {
           "type": "string"
         },
diff --git a/schemas/core/guard.json b/schemas/core/guard.json
index a688e94..2214353 100644
--- a/schemas/core/guard.json
+++ b/schemas/core/guard.json
@@ -27,7 +27,7 @@
       "$ref": "https://json-schema.org/draft/2020-12/schema"
     },
     "history": {
-      "anyOf": [
+      "oneOf": [
         {
           "type": "object",
           "properties": {
@@ -64,7 +64,7 @@
         },
         "on": {
           "description": "A reference to the property this validator should be applied against.  Can be a valid JSON path or a meta-property such as \"prompt\" or \"output\"",
-          "anyOf": [
+          "oneOf": [
             {
               "type": "string",
               "enum": [
diff --git a/schemas/core/outputs.json b/schemas/core/outputs.json
index 47626d9..9fb6ec2 100644
--- a/schemas/core/outputs.json
+++ b/schemas/core/outputs.json
@@ -12,7 +12,7 @@
       "description": "The string content from the LLM response."
     },
     "parsedOutput": {
-      "anyOf": [
+      "oneOf": [
         {
           "type": "string"
         },
@@ -23,7 +23,7 @@
       ]
     },
     "validationResponse": {
-      "anyOf": [
+      "oneOf": [
         {
           "type": "string"
         },
@@ -37,7 +37,7 @@
       ]
     },
     "guardedOutput": {
-      "anyOf": [
+      "oneOf": [
         {
           "type": "string"
         },
diff --git a/schemas/core/validation-outcome.json b/schemas/core/validation-outcome.json
index 9a12428..04dc000 100644
--- a/schemas/core/validation-outcome.json
+++ b/schemas/core/validation-outcome.json
@@ -11,7 +11,7 @@
     },
     "validatedOutput": {
       "description": "The validated, and potentially fixed, output from the LLM call after undergoing validation.",
-      "anyOf": [
+      "oneOf": [
         {
           "type": "string"
         },
diff --git a/schemas/core/validator-log.json b/schemas/core/validator-log.json
index a9c6b3b..ffba4c8 100644
--- a/schemas/core/validator-log.json
+++ b/schemas/core/validator-log.json
@@ -15,7 +15,7 @@
       "format": "kebab-case"
     },
     "instanceId": {
-      "anyOf": [
+      "oneOf": [
         {
           "type": "string"
         },