version: 1.0.184

Reviewed-on: #1

GEMINI.md

@@ -184,6 +184,24 @@ It evaluates as an **Independent Declarative Rules Engine**. Every `Case` block
     *   **`array`**: Homogeneous collection of items matching the `items` schema. Validation is homogeneous, so strictness checking does not apply. `"extensible"` is not applicable at the `array` level (tuple-like `prefixItems` are removed).
 *   **Inheritance Boundaries**: Strictness resets when crossing non-primitive `type` boundaries. A schema extending a strict parent remains strict unless it explicitly overrides with `"extensible": true`.
 
+### Immutable Properties (`"immutable": true`)
+To distinguish read-only hydrated endpoint references, computed properties, system-managed timestamps (`created_at`, `modified_at`), or audit fields from writable properties, JSPG introduces the universal `"immutable": true` schema keyword.
+
+*   **Developer Perspective**: Annotate properties in database schemas or trait definitions with `"immutable": true` when the property should be visible on reads (`jspg_query` / `.response`), but rejected or ignored on writes (`jspg_merge` / `.request`).
+    ```json
+    "properties": {
+      "source": {
+        "family": "lite.organization",
+        "immutable": true,
+        "description": "Read-only hydrated member entity summary on a membership edge."
+      }
+    }
+    ```
+*   **Behavior Across Pillars**:
+    *   **Queryer (`jspg_query`)**: Hydrates and includes `immutable` properties in output read responses without restriction.
+    *   **Validator (`jspg_validate`)**: Context-aware. Returns `IMMUTABLE_PROPERTY_VIOLATION` if an `immutable` property is supplied in a write/request payload (schema IDs not ending in `.response`). Response schemas (`.response`) permit `immutable` fields.
+    *   **Merger (`jspg_merge`)**: Automatically skips `immutable` properties during object graph merging so client payloads can never mutate database columns or relationship edges.
+
 ### Format Leniency for Empty Strings
 To simplify frontend form validation, format validators specifically for `uuid`, `date-time`, and `email` explicitly allow empty strings (`""`), treating them as "present but unset".
 
@@ -302,6 +320,7 @@ JSPG implements specific extensions to the Draft 2020-12 standard to support the
 *   **Missing Type Ultimatum**: If an entity logically requires a discriminator and the JSON payload omits it, JSPG short-circuits branch execution entirely, bubbling a single, perfectly-pathed `MISSING_TYPE` error back to the UI natively to prevent confusing cascading failures.
 *   **Golden Match Context**: When exactly one structural candidate perfectly maps a discriminator, the Validator exclusively cascades that specific structural error context directly to the user, stripping away all noise generated by other parallel schemas.
 *   **Topological Array Pathing**: Instead of relying on explicit `$id` references or injected properties, array iteration paths are dynamically typed based on their compiler boundary constraints. If the array's `items` schema resolves to a topological table-backed entity (e.g., inheriting via a `family` macro tracked in the global DB catalog), the array locks paths and derives element indexes from their actual UUID paths (`array/widget-1/name`), natively enforcing database continuity. If evaluating isolated ad-hoc JSONB elements, strict numeric indexing is enforced natively (`array/1/name`) preventing synthetic payload manipulation.
+*   **Context-Aware Immutability Validation**: `jspg_validate` evaluates the target schema ID context. If the target schema ID does not end with `.response` (inbound write/request context), any property present in the payload marked with `"immutable": true` raises an `IMMUTABLE_PROPERTY_VIOLATION` error. Response schemas (`.response`) permit `immutable` fields for read hydration.
 
 ---
 
@@ -314,13 +333,16 @@ The Merger provides an automated, high-performance graph synchronization engine.
 
 ### Core Features
 
-*   **Caching Strategy**: The Merger leverages the native `compiled_edges` permanently cached onto the Schema AST via `OnceLock` to instantly resolve Foreign Key mapping graphs natively in absolute `O(1)` time. It additionally utilizes the concurrent `GLOBAL_JSPG` application memory (`DashMap`) to cache statically constructed SQL `SELECT` strings used during deduplication (`lk_`) and difference tracking calculations.
+*   **Caching Strategy**: The Merger leverages the native `compiled_edges` permanently cached onto the Schema AST via `OnceLock` to instantly resolve Foreign Key mapping graphs natively in absolute `O(1)` time. It additionally utilizes the concurrent `GLOBAL_JSPG` application memory (`DashMap`) to cache statically constructed SQL `SELECT` strings used during deduplication (`lookup_fields`) and difference tracking calculations.
 *   **Deep Graph Merging**: The Merger walks arbitrary levels of deeply nested JSON schemas (e.g. tracking an `order`, its `customer`, and an array of its `lines`). It intelligently discovers the correct parent-to-child or child-to-parent Foreign Keys stored in the registry and automatically maps the UUIDs across the relationships during UPSERT.
+*   **Immutable Property Filtering**: Properties declaring `"immutable": true` are filtered out during schema property traversal prior to edge classification or column assembly, guaranteeing client payloads cannot write or mutate read-only/computed properties or hydrated endpoint references.
+*   **Factual Creation Dependency Validation**: When `stage_entity` confirms `kind == "create"` via database lookup, `jspg_merge` evaluates `schema.obj.dependencies.get("created")`. If required creation fields are missing from `entity_fields`, `entity_objects`, or `entity_arrays`, `jspg_merge` halts and returns a structured `REQUIRED_FIELD_MISSING` `Drop`.
+*   **Structured Fail-Fast Error Propagation**: Internal merger operations return typed `Result<T, crate::drop::Error>` instances, allowing clean fail-fast `?` traversal and returning `Drop::with_errors(vec![err])` directly at the top-level API boundary on failure.
 *   **Prefix Foreign Key Matching**: Handles scenario where multiple relations point to the same table by using database Foreign Key constraint prefixes (`fk_`). For example, if a schema has `shipping_address` and `billing_address`, the merger resolves against `fk_shipping_address_entity` vs `fk_billing_address_entity` automatically to correctly route object properties.
-*   **Dynamic Deduplication & Lookups**: If a nested object is provided without an `id`, the Merger utilizes Postgres `lk_` index constraints defined in the schema registry (e.g. `lk_person` mapped to `first_name` and `last_name`). It dynamically queries these unique matching constraints to discover the correct UUID to perform an UPDATE, preventing data duplication.
+*   **Dynamic Deduplication & Lookups**: If a nested object is provided without an `id`, the Merger utilizes custom `lookup_fields` declared directly in the schema registry JSON comments. It validates at setup compile-time that a corresponding unique index exists in PostgreSQL for these fields. When merging, it dynamically builds query predicates for any satisfied `lookup_fields` sets in the entity's type hierarchy (checking child-to-parent hierarchies order-independently and combining satisfied keys with `UNION` queries) to discover the correct UUID to perform an UPDATE, preventing data duplication.
 *   **Hierarchical Table Inheritance**: The Punc system uses distributed table inheritance (e.g. `person` inherits `user` inherits `organization` inherits `entity`). The Merger splits the incoming JSON payload and performs atomic row updates across *all* relevant tables in the lineage map.
 *   **The Archive Paradigm**: Data is never deleted in the Punc system. The Merger securely enforces referential integrity by toggling the `archived` Boolean flag on the base `entity` table rather than issuing SQL `DELETE` commands.
-*   **Change Tracking & Reactivity**: The Merger diffs the incoming JSON against the existing database row (utilizing static, `DashMap`-cached `lk_` SELECT string templates). Every detected change is recorded into the `agreego.change` audit table, tracking the user mapping. It then natively uses `pg_notify` to broadcast a completely flat row-level diff out to the Go WebSocket server for O(1) routing.
+*   **Change Tracking & Reactivity**: The Merger diffs the incoming JSON against the existing database row (utilizing static, `DashMap`-cached `lookup` SELECT string templates). Every detected change is recorded into the `agreego.change` audit table, tracking the user mapping. It then natively uses `pg_notify` to broadcast a completely flat row-level diff out to the Go WebSocket server for O(1) routing.
 *   **Flat Structural Beats (Unidirectional Flow)**: The Merger purposefully DOES NOT trace or hydrate outbound Foreign Keys or nested parent structures during writes. It emits completely flat, mathematically perfect structural deltas via `pg_notify` representing only the exact Postgres rows that changed. This guarantees the write-path remains O(1) lightning fast. It is the strict responsibility of the upstream Punc Framework (the Go `Speaker`) to intercept these flat beats, evaluate them against active Websocket Schema Topologies, and dynamically issue targeted `jspg_query` reads to hydrate the exact contextual subgraphs required by listening clients.
 *   **Pre-Order Notification Traversal**: To support proper topological hydration on the upstream Go Framework, the Merger decouples the `pg_notify` execution from the physical database write execution. The engine collects structural changes and explicitly fires `pg_notify` SQL statements in strict **Pre-Order** (Parent -> Relations -> Children). This guarantees that WebSocket clients receive the parent entity `Beat` prior to any nested child entities, ensuring stable unidirectional data flows without hydration race conditions.
 *   **Many-to-Many Graph Edge Management**: Operates seamlessly with the global `agreego.relationship` table, allowing the system to represent and merge arbitrary reified M:M relationships directionally between any two entities.

fixtures/database.json

@@ -911,9 +911,7 @@
               "archived"
             ]
           },
-          "lookup_fields": [
-            "id"
-          ],
+          "lookup_fields": [],
           "historical": true,
           "relationship": false,
           "field_types": {
@@ -1018,5 +1016,100 @@
         }
       }
     ]
+  },
+  {
+    "description": "Validation - lookup fields without matching index",
+    "database": {
+      "types": [
+        {
+          "id": "22222222-2222-2222-2222-222222222222",
+          "type": "type",
+          "name": "user",
+          "module": "test",
+          "source": "test",
+          "hierarchy": ["user"],
+          "variations": ["user"],
+          "fields": ["id", "email"],
+          "lookup_fields": ["email"],
+          "schemas": {
+            "user": {
+              "type": "object",
+              "properties": {
+                "id": { "type": "string", "format": "uuid" },
+                "email": { "type": "string", "format": "email" }
+              }
+            }
+          }
+        }
+      ]
+    },
+    "tests": [
+      {
+        "description": "Fails setup compilation with MISSING_LOOKUP_INDEX if unique index is missing",
+        "action": "compile",
+        "expect": {
+          "success": false,
+          "errors": [
+            {
+              "code": "MISSING_LOOKUP_INDEX",
+              "values": {
+                "type": "user",
+                "lookup_fields": "[\"email\"]"
+              },
+              "details": {
+                "path": "/types/user",
+                "schema": "user"
+              }
+            }
+          ]
+        }
+      }
+    ]
+  },
+  {
+    "description": "Validation - lookup fields with matching index",
+    "database": {
+      "indexes": [
+        {
+          "table": "user",
+          "columns": ["email"]
+        }
+      ],
+      "types": [
+        {
+          "id": "22222222-2222-2222-2222-222222222222",
+          "type": "type",
+          "name": "user",
+          "module": "test",
+          "source": "test",
+          "hierarchy": ["user"],
+          "variations": ["user"],
+          "fields": ["id", "email"],
+          "lookup_fields": ["email"],
+          "schemas": {
+            "user": {
+              "type": "object",
+              "properties": {
+                "id": { "type": "string", "format": "uuid" },
+                "email": { "type": "string", "format": "email" }
+              }
+            }
+          }
+        }
+      ]
+    },
+    "tests": [
+      {
+        "description": "Compiles successfully when unique index matches lookup_fields",
+        "action": "compile",
+        "expect": {
+          "success": true,
+          "schemas": {
+            "user": {},
+            "user.filter": {}
+          }
+        }
+      }
+    ]
   }
 ]

fixtures/merger.json

@@ -117,6 +117,16 @@
           ]
         }
       ],
+      "indexes": [
+        {
+          "table": "person",
+          "columns": ["first_name", "last_name", "date_of_birth", "pronouns"]
+        },
+        {
+          "table": "user",
+          "columns": ["name"]
+        }
+      ],
       "types": [
         {
           "name": "entity",
@@ -296,7 +306,9 @@
               "archived"
             ]
           },
-          "lookup_fields": [],
+          "lookup_fields": [
+            "name"
+          ],
           "historical": true,
           "notify": true,
           "relationship": false
@@ -478,9 +490,7 @@
               "organization_id"
             ]
           },
-          "lookup_fields": [
-            "id"
-          ],
+          "lookup_fields": [],
           "historical": true,
           "notify": true,
           "relationship": false
@@ -1068,9 +1078,7 @@
               "archived"
             ]
           },
-          "lookup_fields": [
-            "id"
-          ],
+          "lookup_fields": [],
           "historical": true,
           "relationship": false,
           "field_types": {
@@ -1593,6 +1601,180 @@
           ]
         }
       },
+      {
+        "description": "Update existing person with id and multiple inherited lookup keys",
+        "action": "merge",
+        "data": {
+          "id": "33333333-3333-3333-3333-333333333333",
+          "type": "person",
+          "name": "LookupName",
+          "first_name": "LookupFirst",
+          "last_name": "LookupLast",
+          "date_of_birth": "1990-01-01T00:00:00Z",
+          "pronouns": "they/them",
+          "contact_id": "abc-contact"
+        },
+        "mocks": [
+          {
+            "id": "22222222-2222-2222-2222-222222222222",
+            "type": "person",
+            "name": "LookupName",
+            "first_name": "LookupFirst",
+            "last_name": "LookupLast",
+            "date_of_birth": "1990-01-01T00:00:00Z",
+            "pronouns": "they/them",
+            "contact_id": "old-contact"
+          }
+        ],
+        "schema_id": "person",
+        "expect": {
+          "success": true,
+          "sql": [
+            [
+              "(SELECT to_jsonb(t1.*) || to_jsonb(t2.*) || to_jsonb(t3.*) || to_jsonb(t4.*)",
+              "FROM agreego.\"entity\" t1",
+              "LEFT JOIN agreego.\"organization\" t2 ON t2.id = t1.id",
+              "LEFT JOIN agreego.\"user\" t3 ON t3.id = t1.id",
+              "LEFT JOIN agreego.\"person\" t4 ON t4.id = t1.id",
+              "WHERE",
+              "  t1.id = '{{uuid:data.id}}'",
+              "UNION SELECT to_jsonb(t1.*) || to_jsonb(t2.*) || to_jsonb(t3.*) || to_jsonb(t4.*)",
+              "FROM agreego.\"entity\" t1",
+              "LEFT JOIN agreego.\"organization\" t2 ON t2.id = t1.id",
+              "LEFT JOIN agreego.\"user\" t3 ON t3.id = t1.id",
+              "LEFT JOIN agreego.\"person\" t4 ON t4.id = t1.id",
+              "WHERE",
+              "  (\"first_name\" = 'LookupFirst'",
+              "  AND \"last_name\" = 'LookupLast'",
+              "  AND \"date_of_birth\" = '{{timestamp}}'",
+              "  AND \"pronouns\" = 'they/them')",
+              "UNION SELECT to_jsonb(t1.*) || to_jsonb(t2.*) || to_jsonb(t3.*) || to_jsonb(t4.*)",
+              "FROM agreego.\"entity\" t1",
+              "LEFT JOIN agreego.\"organization\" t2 ON t2.id = t1.id",
+              "LEFT JOIN agreego.\"user\" t3 ON t3.id = t1.id",
+              "LEFT JOIN agreego.\"person\" t4 ON t4.id = t1.id",
+              "WHERE",
+              "  (\"name\" = 'LookupName'))"
+            ],
+            [
+              "INSERT INTO agreego.\"entity\" (",
+              "  \"created_at\",",
+              "  \"created_by\",",
+              "  \"id\",",
+              "  \"modified_at\",",
+              "  \"modified_by\",",
+              "  \"type\"",
+              ")",
+              "VALUES (",
+              "  '{{timestamp}}',",
+              "  '00000000-0000-0000-0000-000000000000',",
+              "  '{{uuid:data.id}}',",
+              "  '{{timestamp}}',",
+              "  '00000000-0000-0000-0000-000000000000',",
+              "  'person'",
+              ")"
+            ],
+            [
+              "INSERT INTO agreego.\"organization\" (",
+              "  \"id\",",
+              "  \"name\",",
+              "  \"type\"",
+              ")",
+              "VALUES (",
+              "  '{{uuid:data.id}}',",
+              "  'LookupName',",
+              "  'person'",
+              ")"
+            ],
+            [
+              "INSERT INTO agreego.\"user\" (",
+              "  \"id\",",
+              "  \"type\"",
+              ")",
+              "VALUES (",
+              "  '{{uuid:data.id}}',",
+              "  'person'",
+              ")"
+            ],
+            [
+              "INSERT INTO agreego.\"person\" (",
+              "  \"contact_id\",",
+              "  \"date_of_birth\",",
+              "  \"first_name\",",
+              "  \"id\",",
+              "  \"last_name\",",
+              "  \"pronouns\",",
+              "  \"type\"",
+              ")",
+              "VALUES (",
+              "  'abc-contact',",
+              "  '{{timestamp}}',",
+              "  'LookupFirst',",
+              "  '{{uuid:data.id}}',",
+              "  'LookupLast',",
+              "  'they/them',",
+              "  'person'",
+              ")"
+            ],
+            [
+              "INSERT INTO agreego.change (",
+              "  \"old\",",
+              "  \"new\",",
+              "  \"entity_id\",",
+              "  \"id\",",
+              "  \"kind\",",
+              "  \"modified_at\",",
+              "  \"modified_by\"",
+              ")",
+              "VALUES (",
+              "  NULL,",
+              "  '{",
+              "      \"name\": \"LookupName\",",
+              "      \"first_name\": \"LookupFirst\",",
+              "      \"last_name\": \"LookupLast\",",
+              "      \"date_of_birth\": \"{{timestamp}}\",",
+              "      \"pronouns\": \"they/them\",",
+              "      \"contact_id\": \"abc-contact\",",
+              "      \"type\": \"person\"",
+              "  }',",
+              "  '{{uuid:data.id}}',",
+              "  '{{uuid:generated_0}}',",
+              "  'create',",
+              "  '{{timestamp}}',",
+              "  '00000000-0000-0000-0000-000000000000'",
+              ")"
+            ],
+            [
+              "(SELECT pg_notify('entity', '{",
+              "    \"kind\": \"create\",",
+              "    \"complete\": {",
+              "      \"name\": \"LookupName\",",
+              "      \"first_name\": \"LookupFirst\",",
+              "      \"last_name\": \"LookupLast\",",
+              "      \"date_of_birth\": \"{{timestamp}}\",",
+              "      \"pronouns\": \"they/them\",",
+              "      \"contact_id\": \"abc-contact\",",
+              "      \"id\": \"{{uuid:data.id}}\",",
+              "      \"type\": \"person\",",
+              "      \"created_by\": \"00000000-0000-0000-0000-000000000000\",",
+              "      \"created_at\": \"{{timestamp}}\",",
+              "      \"modified_by\": \"00000000-0000-0000-0000-000000000000\",",
+              "      \"modified_at\": \"{{timestamp}}\"",
+              "    },",
+              "    \"new\": {",
+              "      \"name\": \"LookupName\",",
+              "      \"first_name\": \"LookupFirst\",",
+              "      \"last_name\": \"LookupLast\",",
+              "      \"date_of_birth\": \"{{timestamp}}\",",
+              "      \"pronouns\": \"they/them\",",
+              "      \"contact_id\": \"abc-contact\",",
+              "      \"type\": \"person\"",
+              "    }",
+              "}'))"
+            ]
+          ]
+        }
+      },
       {
         "description": "Replace existing person with id and no changes (lookup)",
         "action": "merge",
@@ -2235,12 +2417,7 @@
               "FROM agreego.\"entity\" t1",
               "LEFT JOIN agreego.\"order\" t2 ON t2.id = t1.id",
               "WHERE",
-              "  t1.id = 'abc'",
-              "UNION SELECT to_jsonb(t1.*) || to_jsonb(t2.*)",
-              "FROM agreego.\"entity\" t1",
-              "LEFT JOIN agreego.\"order\" t2 ON t2.id = t1.id",
-              "WHERE",
-              "  (\"id\" = 'abc'))"
+              "  t1.id = 'abc')"
             ],
             [
               "INSERT INTO agreego.\"entity\" (",
@@ -3519,12 +3696,7 @@
               "FROM agreego.\"entity\" t1",
               "LEFT JOIN agreego.\"invoice\" t2 ON t2.id = t1.id",
               "WHERE",
-              "  t1.id = '{{uuid:data.id}}'",
-              "UNION SELECT to_jsonb(t1.*) || to_jsonb(t2.*)",
-              "FROM agreego.\"entity\" t1",
-              "LEFT JOIN agreego.\"invoice\" t2 ON t2.id = t1.id",
-              "WHERE",
-              "  (\"id\" = '{{uuid:data.id}}'))"
+              "  t1.id = '{{uuid:data.id}}')"
             ],
             [
               "INSERT INTO agreego.\"entity\" (",

fixtures/properties.json

@@ -873,5 +873,77 @@
         }
       }
     ]
+  },
+  {
+    "description": "immutable property validation in request vs response context",
+    "database": {
+      "types": [
+        {
+          "name": "item",
+          "schemas": {
+            "save_item.request": {
+              "properties": {
+                "id": {
+                  "type": "string"
+                },
+                "created_at": {
+                  "type": "string",
+                  "immutable": true
+                }
+              }
+            },
+            "get_item.response": {
+              "properties": {
+                "id": {
+                  "type": "string"
+                },
+                "created_at": {
+                  "type": "string",
+                  "immutable": true
+                }
+              }
+            }
+          }
+        }
+      ]
+    },
+    "tests": [
+      {
+        "description": "immutable property in request context causes IMMUTABLE_PROPERTY_VIOLATION",
+        "data": {
+          "id": "123",
+          "created_at": "2026-07-21T00:00:00Z"
+        },
+        "schema_id": "save_item.request",
+        "action": "validate",
+        "expect": {
+          "success": false,
+          "errors": [
+            {
+              "code": "IMMUTABLE_PROPERTY_VIOLATION",
+              "values": {
+                "property_name": "created_at"
+              },
+              "details": {
+                "path": "created_at",
+                "schema": "save_item.request"
+              }
+            }
+          ]
+        }
+      },
+      {
+        "description": "immutable property in response context is allowed",
+        "data": {
+          "id": "123",
+          "created_at": "2026-07-21T00:00:00Z"
+        },
+        "schema_id": "get_item.response",
+        "action": "validate",
+        "expect": {
+          "success": true
+        }
+      }
+    ]
   }
 ]

fixtures/queryer.json

@@ -258,9 +258,7 @@
             "name": "text",
             "created_at": "timestamptz"
           },
-          "lookup_fields": [
-            "id"
-          ],
+          "lookup_fields": [],
           "null_fields": [],
           "default_fields": [
             "id",
@@ -806,9 +804,7 @@
               "archived"
             ]
           },
-          "lookup_fields": [
-            "id"
-          ],
+          "lookup_fields": [],
           "historical": true,
           "relationship": false,
           "field_types": {
@@ -1106,9 +1102,7 @@
               "archived"
             ]
           },
-          "lookup_fields": [
-            "id"
-          ],
+          "lookup_fields": [],
           "historical": true,
           "relationship": false,
           "field_types": {

src/database/mod.rs

@@ -21,16 +21,22 @@ use executors::pgrx::SpiExecutor;
 #[cfg(test)]
 use executors::mock::MockExecutor;
 
+use indexmap::IndexMap;
 use punc::Punc;
 use relation::Relation;
 use schema::Schema;
 use serde_json::Value;
-use indexmap::IndexMap;
 use std::sync::Arc;
 use r#type::Type;
 
 use crate::drop::{Drop, Error, ErrorDetails};
 
+#[derive(serde::Serialize, serde::Deserialize, Debug, Clone)]
+pub struct IndexInfo {
+  pub table: String,
+  pub columns: Vec<String>,
+}
+
 #[derive(serde::Serialize)]
 pub struct Database {
   pub enums: IndexMap<String, Enum>,
@@ -38,6 +44,8 @@ pub struct Database {
   pub puncs: IndexMap<String, Punc>,
   pub relations: IndexMap<String, Relation>,
   #[serde(skip)]
+  pub indexes: Vec<IndexInfo>,
+  #[serde(skip)]
   pub schemas: IndexMap<String, Arc<Schema>>,
   #[serde(skip)]
   pub executor: Box<dyn DatabaseExecutor + Send + Sync>,
@@ -50,6 +58,7 @@ impl Database {
       types: IndexMap::new(),
       relations: IndexMap::new(),
       puncs: IndexMap::new(),
+      indexes: Vec::new(),
       schemas: IndexMap::new(),
       #[cfg(not(test))]
       executor: Box::new(SpiExecutor::new()),
@@ -177,6 +186,25 @@ impl Database {
           }
         }
       }
+
+      if let Some(serde_json::Value::Array(arr)) = map.remove("indexes") {
+        for item in arr {
+          match serde_json::from_value::<IndexInfo>(item) {
+            Ok(idx) => {
+              db.indexes.push(idx);
+            }
+            Err(e) => {
+              errors.push(Error {
+                code: "DATABASE_INDEX_PARSE_FAILED".to_string(),
+                values: Some(IndexMap::from([("reason".to_string(), e.to_string())])),
+                details: ErrorDetails {
+                  ..Default::default()
+                },
+              });
+            }
+          }
+        }
+      }
     }
 
     db.compile(&mut errors);
@@ -214,7 +242,6 @@ impl Database {
     self.executor.timestamp()
   }
 
-
   pub fn compile(&mut self, errors: &mut Vec<crate::drop::Error>) {
     // Phase 1: Registration
     self.collect_schemas(errors);
@@ -260,6 +287,43 @@ impl Database {
           .compile(self, root_id, id.clone(), errors);
       }
     }
+
+    // Phase 5: Verify unique indexes for defined lookup fields
+    for (_, type_def) in &self.types {
+      if !type_def.lookup_fields.is_empty() {
+        let mut index_found = false;
+        for index in &self.indexes {
+          if index.table == type_def.name {
+            if index.columns.len() == type_def.lookup_fields.len()
+              && index
+                .columns
+                .iter()
+                .all(|c| type_def.lookup_fields.contains(c))
+            {
+              index_found = true;
+              break;
+            }
+          }
+        }
+        if !index_found {
+          errors.push(Error {
+            code: "MISSING_LOOKUP_INDEX".to_string(),
+            values: Some(IndexMap::from([
+              ("type".to_string(), type_def.name.clone()),
+              (
+                "lookup_fields".to_string(),
+                format!("{:?}", type_def.lookup_fields),
+              ),
+            ])),
+            details: ErrorDetails {
+              path: Some(format!("/types/{}", type_def.name)),
+              schema: Some(type_def.name.clone()),
+              ..Default::default()
+            },
+          });
+        }
+      }
+    }
   }
 
   /// Synthesizes Composed Filter References for all table-backed boundaries.
@@ -395,7 +459,6 @@ impl Database {
     }
   }
 
-
   /// Inspects the Postgres pg_constraint relations catalog to securely identify
   /// the precise Foreign Key connecting a parent and child hierarchy path.
   pub fn resolve_relation<'a>(

src/database/object.rs

@@ -149,6 +149,9 @@ pub struct SchemaObject {
   #[serde(default)]
   #[serde(skip_serializing_if = "Option::is_none")]
   pub extensible: Option<bool>,
+  #[serde(default)]
+  #[serde(skip_serializing_if = "Option::is_none")]
+  pub immutable: Option<bool>,
 
   // Contains ALL structural fields perfectly flattened from the ENTIRE Database inheritance tree (e.g. `entity` fields like `id`) as well as local fields hidden inside conditional `cases` blocks.
   // This JSON exported array gives clients absolute deterministic visibility to O(1) validation and masking bounds without duplicating structural memory.
@@ -306,4 +309,8 @@ impl SchemaObject {
 
     false
   }
+
+  pub fn is_immutable(&self) -> bool {
+    self.immutable == Some(true)
+  }
 }

src/merger/mod.rs

@@ -48,47 +48,7 @@ impl Merger {
 
     let val_resolved = match result {
       Ok(val) => val,
-      Err(msg) => {
-        let mut final_code = "MERGE_FAILED".to_string();
-        let mut final_message = msg.clone();
-        let mut final_cause = None;
-
-        if let Ok(Value::Object(map)) = serde_json::from_str::<Value>(&msg) {
-          if let (Some(Value::String(e_msg)), Some(Value::String(e_code))) =
-            (map.get("error"), map.get("code"))
-          {
-            final_message = e_msg.clone();
-            final_code = e_code.clone();
-            let mut cause_parts = Vec::new();
-            if let Some(Value::String(d)) = map.get("detail") {
-              if !d.is_empty() {
-                cause_parts.push(d.clone());
-              }
-            }
-            if let Some(Value::String(h)) = map.get("hint") {
-              if !h.is_empty() {
-                cause_parts.push(h.clone());
-              }
-            }
-            if !cause_parts.is_empty() {
-              final_cause = Some(cause_parts.join("\n"));
-            }
-          }
-        }
-
-        return Drop::with_errors(vec![Error {
-          code: final_code,
-          values: Some(IndexMap::from([
-            ("error".to_string(), final_message),
-          ])),
-          details: ErrorDetails {
-            path: None,
-            cause: final_cause,
-            context: None,
-            schema: None,
-          },
-        }]);
-      }
+      Err(err) => return Drop::with_errors(vec![err]),
     };
 
     // Execute the globally collected, pre-ordered notifications last!
@@ -97,11 +57,11 @@ impl Merger {
         return Drop::with_errors(vec![Error {
           code: "MERGE_FAILED".to_string(),
           values: Some(IndexMap::from([
-            ("error".to_string(), e.to_string()),
+            ("error".to_string(), e.clone()),
           ])),
           details: ErrorDetails {
             path: None,
-            cause: None,
+            cause: Some(e),
             context: None,
             schema: None,
           },
@@ -144,7 +104,7 @@ impl Merger {
     notifications: &mut Vec<String>,
     parent_org_id: Option<String>,
     is_child: bool,
-  ) -> Result<Value, String> {
+  ) -> Result<Value, Error> {
     match data {
       Value::Array(items) => {
         self.merge_array(schema, items, notifications, parent_org_id, is_child)
@@ -159,10 +119,14 @@ impl Merger {
                   if let Some(target_schema) = self.db.schemas.get(target_id) {
                     schema = target_schema.clone();
                   } else {
-                    return Err(format!(
-                      "Polymorphic mapped target '{}' not found in database registry",
-                      target_id
-                    ));
+                    return Err(Error {
+                      code: "TARGET_SCHEMA_NOT_FOUND".to_string(),
+                      values: Some(IndexMap::from([("target_id".to_string(), target_id.clone())])),
+                      details: ErrorDetails {
+                        cause: Some(format!("Polymorphic mapped target '{}' not found in database registry", target_id)),
+                        ..Default::default()
+                      },
+                    });
                   }
                 } else if let Some(idx) = idx_opt {
                   if let Some(target_schema) = schema
@@ -173,31 +137,60 @@ impl Merger {
                   {
                     schema = Arc::clone(target_schema);
                   } else {
-                    return Err(format!(
-                      "Polymorphic index target '{}' not found in local oneOf array",
-                      idx
-                    ));
+                    return Err(Error {
+                      code: "ONE_OF_INDEX_NOT_FOUND".to_string(),
+                      values: Some(IndexMap::from([("index".to_string(), idx.to_string())])),
+                      details: ErrorDetails {
+                        cause: Some(format!("Polymorphic index target '{}' not found in local oneOf array", idx)),
+                        ..Default::default()
+                      },
+                    });
                   }
                 } else {
-                  return Err(format!("Polymorphic mapped target has no path"));
+                  return Err(Error {
+                    code: "INVALID_POLYMORPHIC_TARGET".to_string(),
+                    values: None,
+                    details: ErrorDetails {
+                      cause: Some("Polymorphic mapped target has no path".to_string()),
+                      ..Default::default()
+                    },
+                  });
                 }
               } else {
-                return Err(format!(
-                  "Polymorphic discriminator {}='{}' matched no compiled options",
-                  disc, v
-                ));
+                return Err(Error {
+                  code: "DISCRIMINATOR_MISMATCH".to_string(),
+                  values: Some(IndexMap::from([
+                    ("discriminator".to_string(), disc.to_string()),
+                    ("value".to_string(), v.to_string()),
+                  ])),
+                  details: ErrorDetails {
+                    cause: Some(format!("Polymorphic discriminator {}='{}' matched no compiled options", disc, v)),
+                    ..Default::default()
+                  },
+                });
               }
             } else {
-              return Err(format!(
-                "Polymorphic merging failed: missing required discriminator '{}'",
-                disc
-              ));
+              return Err(Error {
+                code: "MISSING_DISCRIMINATOR".to_string(),
+                values: Some(IndexMap::from([("discriminator".to_string(), disc.to_string())])),
+                details: ErrorDetails {
+                  cause: Some(format!("Polymorphic merging failed: missing required discriminator '{}'", disc)),
+                  ..Default::default()
+                },
+              });
             }
           }
         }
         self.merge_object(schema, map, notifications, parent_org_id, is_child)
       }
-      _ => Err("Invalid merge payload: root must be an Object or Array".to_string()),
+      _ => Err(Error {
+        code: "INVALID_MERGE_PAYLOAD".to_string(),
+        values: None,
+        details: ErrorDetails {
+          cause: Some("Invalid merge payload: root must be an Object or Array".to_string()),
+          ..Default::default()
+        },
+      }),
     }
   }
 
@@ -208,7 +201,7 @@ impl Merger {
     notifications: &mut Vec<String>,
     parent_org_id: Option<String>,
     is_child: bool,
-  ) -> Result<Value, String> {
+  ) -> Result<Value, Error> {
     let mut item_schema = schema.clone();
     if let Some(crate::database::object::SchemaTypeOrArray::Single(t)) = &schema.obj.type_ {
       if t == "array" {
@@ -239,22 +232,49 @@ impl Merger {
     notifications: &mut Vec<String>,
     parent_org_id: Option<String>,
     is_child: bool,
-  ) -> Result<Value, String> {
+  ) -> Result<Value, Error> {
     let queue_start = notifications.len();
 
     let type_name = match obj.get("type").and_then(|v| v.as_str()) {
       Some(t) => t.to_string(),
-      None => return Err("Missing required 'type' field on object".to_string()),
+      None => {
+        return Err(Error {
+          code: "MISSING_TYPE".to_string(),
+          values: None,
+          details: ErrorDetails {
+            cause: Some("Missing required 'type' field on object".to_string()),
+            ..Default::default()
+          },
+        });
+      }
     };
 
     let type_def = match self.db.types.get(&type_name) {
       Some(t) => t,
-      None => return Err(format!("Unknown entity type: {}", type_name)),
+      None => {
+        return Err(Error {
+          code: "UNKNOWN_ENTITY_TYPE".to_string(),
+          values: Some(IndexMap::from([("type".to_string(), type_name.clone())])),
+          details: ErrorDetails {
+            cause: Some(format!("Unknown entity type: {}", type_name)),
+            ..Default::default()
+          },
+        });
+      }
     };
 
     let compiled_props = match schema.obj.compiled_properties.get() {
       Some(props) => props,
-      None => return Err("Schema has no compiled properties for merging".to_string()),
+      None => {
+        return Err(Error {
+          code: "UNCOMPILED_SCHEMA".to_string(),
+          values: None,
+          details: ErrorDetails {
+            cause: Some("Schema has no compiled properties for merging".to_string()),
+            ..Default::default()
+          },
+        });
+      }
     };
 
     let mut entity_fields = serde_json::Map::new();
@@ -269,6 +289,10 @@ impl Merger {
       }
 
       if let Some(prop_schema) = compiled_props.get(&k) {
+        if prop_schema.is_immutable() {
+          continue;
+        }
+
         let mut is_edge = false;
         if let Some(edges) = schema.obj.compiled_edges.get() {
           if edges.contains_key(&k) {
@@ -312,8 +336,22 @@ impl Merger {
       current_org_id = parent_org_id.clone();
     }
 
-    let user_id = self.db.auth_user_id()?;
-    let timestamp = self.db.timestamp()?;
+    let user_id = self.db.auth_user_id().map_err(|e| Error {
+      code: "AUTH_USER_FAILED".to_string(),
+      values: Some(IndexMap::from([("error".to_string(), e.clone())])),
+      details: ErrorDetails {
+        cause: Some(e),
+        ..Default::default()
+      },
+    })?;
+    let timestamp = self.db.timestamp().map_err(|e| Error {
+      code: "TIMESTAMP_FAILED".to_string(),
+      values: Some(IndexMap::from([("error".to_string(), e.clone())])),
+      details: ErrorDetails {
+        cause: Some(e),
+        ..Default::default()
+      },
+    })?;
 
     let mut entity_change_kind = None;
     let mut entity_fetched = None;
@@ -328,6 +366,27 @@ impl Merger {
       entity_replaces = replaces;
 
       if entity_change_kind.as_deref() == Some("create") {
+        if let Some(deps) = &schema.obj.dependencies {
+          if let Some(crate::database::object::Dependency::Props(req_props)) = deps.get("created") {
+            for req in req_props {
+              if !entity_fields.contains_key(req) && !entity_objects.contains_key(req) && !entity_arrays.contains_key(req) {
+                return Err(Error {
+                  code: "REQUIRED_FIELD_MISSING".to_string(),
+                  values: Some(IndexMap::from([
+                    ("property_name".to_string(), req.to_string()),
+                    ("entity_type".to_string(), type_name.clone()),
+                  ])),
+                  details: ErrorDetails {
+                    path: Some(req.to_string()),
+                    cause: Some(format!("Missing required creation field '{}' for entity {}", req, type_name)),
+                    ..Default::default()
+                  },
+                });
+              }
+            }
+          }
+        }
+
         if is_child {
           if !entity_fields.contains_key("organization_id") {
             if let Some(ref org_id) = current_org_id {
@@ -538,7 +597,7 @@ impl Merger {
       Option<serde_json::Map<String, Value>>,
       Option<String>,
     ),
-    String,
+    Error,
   > {
     let type_name = type_def.name.as_str();
 
@@ -673,14 +732,16 @@ impl Merger {
     &self,
     entity_fields: &serde_json::Map<String, Value>,
     entity_type: &crate::database::r#type::Type,
-  ) -> Result<Option<serde_json::Map<String, Value>>, String> {
+  ) -> Result<Option<serde_json::Map<String, Value>>, Error> {
     let id_val = entity_fields.get("id");
     let entity_type_name = entity_type.name.as_str();
 
-    let mut lookup_complete = false;
-    if !entity_type.lookup_fields.is_empty() {
-      lookup_complete = true;
-      for column in &entity_type.lookup_fields {
+    let mut lookup_satisfied_keys = Vec::new();
+    for parent_type_name in entity_type.hierarchy.iter().rev() {
+      if let Some(parent_type) = self.db.types.get(parent_type_name) {
+        if !parent_type.lookup_fields.is_empty() {
+          let mut lookup_complete = true;
+          for column in &parent_type.lookup_fields {
             match entity_fields.get(column) {
               Some(Value::Null) | None => {
                 lookup_complete = false;
@@ -693,9 +754,14 @@ impl Merger {
               _ => {}
             }
           }
+          if lookup_complete {
+            lookup_satisfied_keys.push(&parent_type.lookup_fields);
+          }
+        }
+      }
     }
 
-    if id_val.is_none() && !lookup_complete {
+    if id_val.is_none() && lookup_satisfied_keys.is_empty() {
       return Ok(None);
     }
 
@@ -727,9 +793,9 @@ impl Merger {
       where_parts.push(format!("t1.id = {}", Self::quote_literal(id)));
     }
 
-    if lookup_complete {
+    for lookup_fields in lookup_satisfied_keys {
       let mut lookup_predicates = Vec::new();
-      for column in &entity_type.lookup_fields {
+      for column in lookup_fields {
         let val = entity_fields.get(column).unwrap_or(&Value::Null);
         if column == "type" {
           lookup_predicates.push(format!("t1.\"{}\" = {}", column, Self::quote_literal(val)));
@@ -757,22 +823,47 @@ impl Merger {
     let fetched = match self.db.query(&final_sql, None) {
       Ok(Value::Array(table)) => {
         if table.len() > 1 {
-          Err(format!(
-            "TOO_MANY_LOOKUP_ROWS: Lookup for {} found too many existing rows",
-            entity_type_name
-          ))
+          Err(Error {
+            code: "TOO_MANY_LOOKUP_ROWS".to_string(),
+            values: Some(IndexMap::from([("entity_type".to_string(), entity_type_name.to_string())])),
+            details: ErrorDetails {
+              cause: Some(format!("Lookup for {} found too many existing rows", entity_type_name)),
+              ..Default::default()
+            },
+          })
         } else if table.is_empty() {
           Ok(None)
         } else {
           let row = table.first().unwrap();
           match row {
             Value::Object(map) => Ok(Some(map.clone())),
-            other => Err(format!("Expected JSON object, got: {:?}", other)),
+            other => Err(Error {
+              code: "UNEXPECTED_QUERY_RESULT".to_string(),
+              values: None,
+              details: ErrorDetails {
+                cause: Some(format!("Expected JSON object, got: {:?}", other)),
+                ..Default::default()
+              },
+            }),
           }
         }
       }
-      Ok(_) => Err("Expected array from query in fetch_entity".to_string()),
-      Err(e) => Err(format!("SPI error in fetch_entity: {:?}", e)),
+      Ok(_) => Err(Error {
+        code: "UNEXPECTED_QUERY_RESULT".to_string(),
+        values: None,
+        details: ErrorDetails {
+          cause: Some("Expected array from query in fetch_entity".to_string()),
+          ..Default::default()
+        },
+      }),
+      Err(e) => Err(Error {
+        code: "DATABASE_SPI_ERROR".to_string(),
+        values: Some(IndexMap::from([("error".to_string(), e.clone())])),
+        details: ErrorDetails {
+          cause: Some(format!("SPI error in fetch_entity: {:?}", e)),
+          ..Default::default()
+        },
+      }),
     }?;
 
     Ok(fetched)
@@ -785,23 +876,36 @@ impl Merger {
     entity_type: &crate::database::r#type::Type,
     entity_fields: &serde_json::Map<String, Value>,
     _entity_fetched: Option<&serde_json::Map<String, Value>>,
-  ) -> Result<(), String> {
+  ) -> Result<(), Error> {
     if change_kind.is_empty() {
       return Ok(());
     }
 
     let id_str = match entity_fields.get("id").and_then(|v| v.as_str()) {
       Some(id) => id,
-      None => return Err("Missing 'id' for merge execution".to_string()),
+      None => {
+        return Err(Error {
+          code: "MISSING_ENTITY_ID".to_string(),
+          values: None,
+          details: ErrorDetails {
+            cause: Some("Missing 'id' for merge execution".to_string()),
+            ..Default::default()
+          },
+        });
+      }
     };
 
     let grouped_fields = match &entity_type.grouped_fields {
       Some(Value::Object(map)) => map,
       _ => {
-        return Err(format!(
-          "Grouped fields missing for type {}",
-          entity_type_name
-        ));
+        return Err(Error {
+          code: "MISSING_GROUPED_FIELDS".to_string(),
+          values: Some(IndexMap::from([("type".to_string(), entity_type_name.to_string())])),
+          details: ErrorDetails {
+            cause: Some(format!("Grouped fields missing for type {}", entity_type_name)),
+            ..Default::default()
+          },
+        });
       }
     };
 
@@ -854,7 +958,16 @@ impl Merger {
           columns.join(", "),
           values.join(", ")
         );
-        self.db.execute(&sql, None)?;
+        if let Err(e) = self.db.execute(&sql, None) {
+          return Err(Error {
+            code: "DATABASE_SPI_ERROR".to_string(),
+            values: Some(IndexMap::from([("error".to_string(), e.clone())])),
+            details: ErrorDetails {
+              cause: Some(e),
+              ..Default::default()
+            },
+          });
+        }
       } else if change_kind == "update" || change_kind == "delete" {
         entity_pairs.remove("id");
         entity_pairs.remove("type");
@@ -886,7 +999,16 @@ impl Merger {
           set_clauses.join(", "),
           Self::quote_literal(&Value::String(id_str.to_string()))
         );
-        self.db.execute(&sql, None)?;
+        if let Err(e) = self.db.execute(&sql, None) {
+          return Err(Error {
+            code: "DATABASE_SPI_ERROR".to_string(),
+            values: Some(IndexMap::from([("error".to_string(), e.clone())])),
+            details: ErrorDetails {
+              cause: Some(e),
+              ..Default::default()
+            },
+          });
+        }
       }
     }
 
@@ -902,7 +1024,7 @@ impl Merger {
     user_id: &str,
     timestamp: &str,
     replaces_id: Option<&str>,
-  ) -> Result<Option<String>, String> {
+  ) -> Result<Option<String>, Error> {
     let change_kind = match entity_change_kind {
       Some(k) => k,
       None => return Ok(None),
@@ -995,7 +1117,16 @@ impl Merger {
         Self::quote_literal(&Value::String(user_id.to_string()))
       );
 
-      self.db.execute(&change_sql, None)?;
+      if let Err(e) = self.db.execute(&change_sql, None) {
+        return Err(Error {
+          code: "DATABASE_SPI_ERROR".to_string(),
+          values: Some(IndexMap::from([("error".to_string(), e.clone())])),
+          details: ErrorDetails {
+            cause: Some(e),
+            ..Default::default()
+          },
+        });
+      }
     }
 
     if type_obj.notify {

src/tests/fixtures.rs

@@ -2519,6 +2519,18 @@ fn test_properties_12_0() {
     crate::tests::runner::run_test_case(&path, 12, 0).unwrap();
 }
 
+#[test]
+fn test_properties_13_0() {
+    let path = format!("{}/fixtures/properties.json", env!("CARGO_MANIFEST_DIR"));
+    crate::tests::runner::run_test_case(&path, 13, 0).unwrap();
+}
+
+#[test]
+fn test_properties_13_1() {
+    let path = format!("{}/fixtures/properties.json", env!("CARGO_MANIFEST_DIR"));
+    crate::tests::runner::run_test_case(&path, 13, 1).unwrap();
+}
+
 #[test]
 fn test_max_contains_0_0() {
     let path = format!("{}/fixtures/maxContains.json", env!("CARGO_MANIFEST_DIR"));
@@ -3407,6 +3419,18 @@ fn test_database_6_0() {
     crate::tests::runner::run_test_case(&path, 6, 0).unwrap();
 }
 
+#[test]
+fn test_database_7_0() {
+    let path = format!("{}/fixtures/database.json", env!("CARGO_MANIFEST_DIR"));
+    crate::tests::runner::run_test_case(&path, 7, 0).unwrap();
+}
+
+#[test]
+fn test_database_8_0() {
+    let path = format!("{}/fixtures/database.json", env!("CARGO_MANIFEST_DIR"));
+    crate::tests::runner::run_test_case(&path, 8, 0).unwrap();
+}
+
 #[test]
 fn test_cases_0_0() {
     let path = format!("{}/fixtures/cases.json", env!("CARGO_MANIFEST_DIR"));
@@ -7666,3 +7690,9 @@ fn test_merger_0_15() {
     let path = format!("{}/fixtures/merger.json", env!("CARGO_MANIFEST_DIR"));
     crate::tests::runner::run_test_case(&path, 0, 15).unwrap();
 }
+
+#[test]
+fn test_merger_0_16() {
+    let path = format!("{}/fixtures/merger.json", env!("CARGO_MANIFEST_DIR"));
+    crate::tests::runner::run_test_case(&path, 0, 16).unwrap();
+}

src/validator/context.rs

@@ -16,6 +16,7 @@ pub struct ValidationContext<'a> {
   pub reporter: bool,
   pub overrides: HashSet<String>,
   pub parents: Vec<&'a serde_json::Value>,
+  pub response: bool,
 }
 
 impl<'a> ValidationContext<'a> {
@@ -27,6 +28,7 @@ impl<'a> ValidationContext<'a> {
     overrides: HashSet<String>,
     extensible: bool,
     reporter: bool,
+    response: bool,
   ) -> Self {
     let effective_extensible = schema.extensible.unwrap_or(extensible);
     Self {
@@ -40,6 +42,7 @@ impl<'a> ValidationContext<'a> {
       reporter,
       overrides,
       parents: Vec::new(),
+      response,
     }
   }
 
@@ -79,6 +82,7 @@ impl<'a> ValidationContext<'a> {
       reporter,
       overrides,
       parents,
+      response: self.response,
     }
   }
 

src/validator/mod.rs

@@ -48,6 +48,7 @@ impl Validator {
     let schema_opt = self.db.schemas.get(schema_id);
 
     if let Some(schema) = schema_opt {
+      let response = schema_id.ends_with(".response");
       let ctx = ValidationContext::new(
         &self.db,
         &schema,
@@ -56,6 +57,7 @@ impl Validator {
         HashSet::new(),
         false,
         false,
+        response,
       );
       match ctx.validate_scoped() {
         Ok(result) => {

src/validator/rules/object.rs

@@ -179,6 +179,34 @@ impl<'a> ValidationContext<'a> {
         }
       }
 
+      if !self.response {
+        if let Some(compiled_props) = self.schema.compiled_properties.get() {
+          for (key, sub_schema) in compiled_props {
+            if sub_schema.is_immutable() && obj.contains_key(key) {
+              result.errors.push(ValidationError {
+                code: "IMMUTABLE_PROPERTY_VIOLATION".to_string(),
+                values: Some(IndexMap::from([
+                  ("property_name".to_string(), key.to_string()),
+                ])),
+                path: self.join_path(key),
+              });
+            }
+          }
+        } else if let Some(props) = &self.schema.properties {
+          for (key, sub_schema) in props {
+            if sub_schema.is_immutable() && obj.contains_key(key) {
+              result.errors.push(ValidationError {
+                code: "IMMUTABLE_PROPERTY_VIOLATION".to_string(),
+                values: Some(IndexMap::from([
+                  ("property_name".to_string(), key.to_string()),
+                ])),
+                path: self.join_path(key),
+              });
+            }
+          }
+        }
+      }
+
       if let Some(props) = &self.schema.properties {
         for (key, sub_schema) in props {
           if self.overrides.contains(key) {
@@ -228,6 +256,7 @@ impl<'a> ValidationContext<'a> {
             HashSet::new(),
             self.extensible,
             self.reporter,
+            self.response,
           );
 
           result.merge(ctx.validate()?);

version

@@ -1 +1 @@
-1.0.181
+1.0.184