diff --git a/mlf-codegen/src/lib.rs b/mlf-codegen/src/lib.rs
index cf65b3d..501fa94 100644
--- a/mlf-codegen/src/lib.rs
+++ b/mlf-codegen/src/lib.rs
@@ -405,30 +405,33 @@ fn generate_query_json(query: &Query, usage_counts: &HashMap<String, usize>, wor
     let output_encoding = get_encoding_annotation(&query.annotations, "output")
         .unwrap_or_else(|| "application/json".to_string());
 
-    let output = match &query.returns {
-        ReturnType::None { .. } => None,
+    let (output, errors) = match &query.returns {
+        ReturnType::None { .. } => (None, None),
         ReturnType::Type(ty) => {
             let mut output_obj = Map::new();
             output_obj.insert("encoding".to_string(), json!(output_encoding));
             output_obj.insert("schema".to_string(), generate_type_json(ty, usage_counts, workspace, current_namespace));
-            Some(Value::Object(output_obj))
+            (Some(Value::Object(output_obj)), None)
         }
         ReturnType::TypeWithErrors { success, errors, .. } => {
-            let mut error_defs = Map::new();
+            let mut error_array = Vec::new();
             for error in errors {
-                error_defs.insert(
-                    error.name.name.clone(),
+                let error_docs = extract_docs(&error.docs);
+                let error_obj = if error_docs.is_empty() {
+                    json!({ "name": error.name.name.clone() })
+                } else {
                     json!({
-                        "description": extract_docs(&error.docs)
-                    }),
-                );
+                        "name": error.name.name.clone(),
+                        "description": error_docs
+                    })
+                };
+                error_array.push(error_obj);
             }
 
             let mut output_obj = Map::new();
             output_obj.insert("encoding".to_string(), json!(output_encoding));
             output_obj.insert("schema".to_string(), generate_type_json(success, usage_counts, workspace, current_namespace));
-            output_obj.insert("errors".to_string(), json!(error_defs));
-            Some(Value::Object(output_obj))
+            (Some(Value::Object(output_obj)), Some(Value::Array(error_array)))
         }
     };
 
@@ -439,6 +442,9 @@ fn generate_query_json(query: &Query, usage_counts: &HashMap<String, usize>, wor
     if let Some(output_val) = output {
         query_obj.insert("output".to_string(), output_val);
     }
+    if let Some(errors_val) = errors {
+        query_obj.insert("errors".to_string(), errors_val);
+    }
     Value::Object(query_obj)
 }
 
@@ -482,30 +488,33 @@ fn generate_procedure_json(procedure: &Procedure, usage_counts: &HashMap<String,
     let output_encoding = get_encoding_annotation(&procedure.annotations, "output")
         .unwrap_or_else(|| "application/json".to_string());
 
-    let output = match &procedure.returns {
-        ReturnType::None { .. } => None,
+    let (output, errors) = match &procedure.returns {
+        ReturnType::None { .. } => (None, None),
         ReturnType::Type(ty) => {
             let mut output_obj = Map::new();
             output_obj.insert("encoding".to_string(), json!(output_encoding));
             output_obj.insert("schema".to_string(), generate_type_json(ty, usage_counts, workspace, current_namespace));
-            Some(Value::Object(output_obj))
+            (Some(Value::Object(output_obj)), None)
         }
         ReturnType::TypeWithErrors { success, errors, .. } => {
-            let mut error_defs = Map::new();
+            let mut error_array = Vec::new();
             for error in errors {
-                error_defs.insert(
-                    error.name.name.clone(),
+                let error_docs = extract_docs(&error.docs);
+                let error_obj = if error_docs.is_empty() {
+                    json!({ "name": error.name.name.clone() })
+                } else {
                     json!({
-                        "description": extract_docs(&error.docs)
-                    }),
-                );
+                        "name": error.name.name.clone(),
+                        "description": error_docs
+                    })
+                };
+                error_array.push(error_obj);
             }
 
             let mut output_obj = Map::new();
             output_obj.insert("encoding".to_string(), json!(output_encoding));
             output_obj.insert("schema".to_string(), generate_type_json(success, usage_counts, workspace, current_namespace));
-            output_obj.insert("errors".to_string(), json!(error_defs));
-            Some(Value::Object(output_obj))
+            (Some(Value::Object(output_obj)), Some(Value::Array(error_array)))
         }
     };
 
@@ -518,6 +527,9 @@ fn generate_procedure_json(procedure: &Procedure, usage_counts: &HashMap<String,
     if let Some(output_val) = output {
         result.insert("output".to_string(), output_val);
     }
+    if let Some(errors_val) = errors {
+        result.insert("errors".to_string(), errors_val);
+    }
     Value::Object(result)
 }
 
diff --git a/website/content/_index.md b/website/content/_index.md
index f1fbef5..07aab13 100644
--- a/website/content/_index.md
+++ b/website/content/_index.md
@@ -23,6 +23,7 @@ record thread {
 
 json_example = '''```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.thread",
   "defs": {
@@ -36,14 +37,14 @@ json_example = '''```json
         "properties": {
           "title": {
             "type": "string",
-            "description": "Thread title",
             "maxLength": 200,
-            "minLength": 1
+            "minLength": 1,
+            "description": "Thread title"
           },
           "body": {
             "type": "string",
-            "description": "Thread body content",
-            "maxLength": 10000
+            "maxLength": 10000,
+            "description": "Thread body content"
           },
           "createdAt": {
             "type": "string",
diff --git a/website/content/docs/cli/06-generate.md b/website/content/docs/cli/06-generate.md
index 37598c8..9932e1b 100644
--- a/website/content/docs/cli/06-generate.md
+++ b/website/content/docs/cli/06-generate.md
@@ -340,11 +340,13 @@ mlf generate mlf -i dist/lexicons/com/example/thread.json -o ./src/
 **Input JSON:**
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.thread",
   "defs": {
     "main": {
       "type": "record",
+      "key": "tid",
       "record": {
         "type": "object",
         "required": ["title", "createdAt"],
diff --git a/website/content/docs/language-guide/01-your-first-lexicon.md b/website/content/docs/language-guide/01-your-first-lexicon.md
index fdc9aac..248b5fb 100644
--- a/website/content/docs/language-guide/01-your-first-lexicon.md
+++ b/website/content/docs/language-guide/01-your-first-lexicon.md
@@ -41,6 +41,7 @@ When you compile this MLF file, it generates a JSON lexicon:
 
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.forum.profile",
   "defs": {
diff --git a/website/content/docs/language-guide/10-important-info.md b/website/content/docs/language-guide/10-important-info.md
index 1f7af32..b96b175 100644
--- a/website/content/docs/language-guide/10-important-info.md
+++ b/website/content/docs/language-guide/10-important-info.md
@@ -42,6 +42,7 @@ record post {
 This generates:
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.forum.post",
   "defs": {
@@ -72,6 +73,7 @@ The `post` record becomes `"main"`, while `author` becomes a named def:
 
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.forum.post",
   "defs": {
@@ -105,6 +107,7 @@ record reply {    // Doesn't match "thread"
 Generates:
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.forum.thread",
   "defs": {
diff --git a/website/content/docs/language-guide/11-lexicon-mapping.md b/website/content/docs/language-guide/11-lexicon-mapping.md
index 1c5a658..643fb8c 100644
--- a/website/content/docs/language-guide/11-lexicon-mapping.md
+++ b/website/content/docs/language-guide/11-lexicon-mapping.md
@@ -23,6 +23,7 @@ record post {
 **Generated JSON:**
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.forum.post",
   "defs": {
@@ -71,6 +72,7 @@ query getPost(
 **Generated JSON:**
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.forum.getPost",
   "defs": {
@@ -94,8 +96,12 @@ query getPost(
         }
       },
       "errors": [
-        { "name": "NotFound" },
-        { "name": "BadRequest" }
+        {
+          "name": "NotFound"
+        },
+        {
+          "name": "BadRequest"
+        }
       ]
     }
   }
@@ -126,6 +132,7 @@ procedure createPost(
 **Generated JSON:**
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.forum.createPost",
   "defs": {
@@ -161,7 +168,9 @@ procedure createPost(
         }
       },
       "errors": [
-        { "name": "TextTooLong" }
+        {
+          "name": "TextTooLong"
+        }
       ]
     }
   }
@@ -197,6 +206,7 @@ def type identity = {
 **Generated JSON:**
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.subscribeEvents",
   "defs": {
@@ -266,11 +276,13 @@ def type postMetadata = {
 **Generated JSON:**
 ```json
 {
+  "$type": "com.atproto.lexicon.schema",
   "lexicon": 1,
   "id": "com.example.post",
   "defs": {
     "main": {
       "type": "record",
+      "key": "tid",
       "record": {
         "type": "object",
         "properties": {