diff --git a/compiler/src/main/scala/com/rawlabs/compiler/CompilerServiceProvider.scala b/compiler/src/main/scala/com/rawlabs/compiler/CompilerServiceProvider.scala
index 1a670e1e2..307776499 100644
--- a/compiler/src/main/scala/com/rawlabs/compiler/CompilerServiceProvider.scala
+++ b/compiler/src/main/scala/com/rawlabs/compiler/CompilerServiceProvider.scala
@@ -54,11 +54,11 @@ object CompilerServiceProvider {
   private def build(language: String)(implicit settings: RawSettings): CompilerService = {
     val services = ServiceLoader.load(classOf[CompilerServiceBuilder]).asScala.toArray
     if (services.isEmpty) {
-      throw new CompilerException("no compiler service available")
+      throw new AssertionError("no compiler service available")
     } else {
       services.find(p => p.language.contains(language)) match {
         case Some(builder) => builder.build
-        case None => throw new CompilerException(s"cannot find compiler service: $language")
+        case None => throw new AssertionError(s"cannot find compiler service: $language")
       }
     }
   }
diff --git a/compiler/src/main/scala/com/rawlabs/compiler/Errors.scala b/compiler/src/main/scala/com/rawlabs/compiler/Errors.scala
index a78168e37..7363e353f 100644
--- a/compiler/src/main/scala/com/rawlabs/compiler/Errors.scala
+++ b/compiler/src/main/scala/com/rawlabs/compiler/Errors.scala
@@ -12,29 +12,15 @@
 
 package com.rawlabs.compiler
 
-import com.fasterxml.jackson.annotation.{JsonSubTypes, JsonTypeInfo}
-import com.fasterxml.jackson.annotation.JsonSubTypes.{Type => JsonType}
-import com.rawlabs.utils.core.RawException
-
 /**
  * Used for errors that are found during semantic analysis.
- * message The error message.
- * positions The positions where the error occurred.
- * severity The severity of the error. 1 = Hint, 2 = Info, 4 = Warning, 8 = Error (compliant with monaco editor).
- * - The below two should only be set by compiler errors
- * code An optional error code.
- * tags Indication for the error Unnecessary = 1, Deprecated = 2 (compliant with monaco editor).
+ *
+ * - message: The error message.
+ * - positions: The positions where the error occurred.
+ * - severity: The severity of the error. 1 = Hint, 2 = Info, 4 = Warning, 8 = Error (compliant with monaco editor).
+ * - code: An optional error code (should only be set by compiler errors)
+ * - tags: Indication for the error Unnecessary = 1, Deprecated = 2 (compliant with monaco editor).
  */
-
-@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
-@JsonSubTypes(
-  Array(
-    new JsonType(value = classOf[HintMessage], name = "hint"),
-    new JsonType(value = classOf[InfoMessage], name = "info"),
-    new JsonType(value = classOf[WarningMessage], name = "warning"),
-    new JsonType(value = classOf[ErrorMessage], name = "hint")
-  )
-)
 sealed trait Message {
   val message: String
   val positions: List[ErrorRange]
@@ -77,18 +63,3 @@ final case class ErrorMessage(
 
 final case class ErrorRange(begin: ErrorPosition, end: ErrorPosition)
 final case class ErrorPosition(line: Int, column: Int)
-
-/**
- * Used for exceptions that are thrown by the compiler itself.
- * Must abort compilation.
- * Should NOT BE USED for:
- * - semantic analysis errors or other normal errors since there is no tracking of positions.
- * - errors during execution.
- * Should BE USED for:
- * - errors that are not found during type checking but which prevent the compiler from proceeding, e.g.
- *   missing implementations or the like.
- * Parsing may throw this exception if they encounter an error that they cannot recover from.
- *
- * The message can be safely shared with the user.
- */
-sealed class CompilerException(message: String, cause: Throwable = null) extends RawException(message, cause)
diff --git a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/completions.proto b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/completions.proto
new file mode 100644
index 000000000..467ff42c6
--- /dev/null
+++ b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/completions.proto
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2024 RAW Labs S.A.
+ *
+ * Use of this software is governed by the Business Source License
+ * included in the file licenses/BSL.txt.
+ *
+ * As of the Change Date specified in that file, in accordance with
+ * the Business Source License, use of this software will be governed
+ * by the Apache License, Version 2.0, included in the file
+ * licenses/APL.txt.
+ */
+
+syntax = "proto3";
+
+option java_package = "com.rawlabs.protocol.compiler";
+option java_multiple_files = true;
+
+import "com/rawlabs/protocol/compiler/docs.proto";
+
+package com.rawlabs.protocol.compiler;
+
+message Completion {
+  oneof completion {
+    TypeCompletion type = 1;
+    FieldCompletion field = 2;
+    LetBindCompletion letBind = 3;
+    LetFunCompletion letFun = 4;
+    LetFunRecCompletion letFunRec = 5;
+    FunParamCompletion funParam = 6;
+    PackageCompletion package = 7;
+    EntryCompletion entry = 8;
+  }
+}
+
+message TypeCompletion {
+  string name = 1;
+  string type = 2;
+}
+
+message FieldCompletion {
+  string name = 1;
+  string type = 2;
+}
+
+message LetBindCompletion {
+  string name = 1;
+  string type = 2;
+}
+
+message LetFunCompletion {
+  string name = 1;
+  string type = 2;
+}
+
+message LetFunRecCompletion {
+  string name = 1;
+  string type = 2;
+}
+
+message FunParamCompletion {
+  string name = 1;
+  string type = 2;
+}
+
+message PackageCompletion {
+  string name = 1;
+  PackageDoc doc = 2;
+}
+
+message EntryCompletion {
+  string name = 1;
+  EntryDoc doc = 2;
+}
\ No newline at end of file
diff --git a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/docs.proto b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/docs.proto
index ed9d852d0..4b64d019b 100644
--- a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/docs.proto
+++ b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/docs.proto
@@ -24,11 +24,6 @@ message PackageDoc {
   optional string danger = 4;
 }
 
-message EntryCompletion {
-  string name = 1;
-  EntryDoc doc = 2;
-}
-
 message EntryDoc {
   string summary = 1;
   optional string description = 2;
diff --git a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/location_config.proto b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/location_config.proto
index 751a42359..621696d70 100644
--- a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/location_config.proto
+++ b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/location_config.proto
@@ -1,3 +1,15 @@
+/*
+ * Copyright 2024 RAW Labs S.A.
+ *
+ * Use of this software is governed by the Business Source License
+ * included in the file licenses/BSL.txt.
+ *
+ * As of the Change Date specified in that file, in accordance with
+ * the Business Source License, use of this software will be governed
+ * by the Apache License, Version 2.0, included in the file
+ * licenses/APL.txt.
+ */
+
 syntax = "proto3";
 
 option java_package = "com.rawlabs.protocol.compiler";
@@ -6,148 +18,148 @@ option java_multiple_files = true;
 package com.rawlabs.protocol.compiler;
 
 message LocationConfig {
-    oneof config {
-        S3Config s3 = 1;
-        MySqlConfig mysql = 2;
-        OracleConfig oracle = 3;
-        PostgreSQLConfig postgresql = 4;
-        SQLServerConfig sqlserver = 5;
-        SnowflakeConfig snowflake = 6;
-        SqliteConfig sqlite = 7;
-        TeradataConfig teradata = 8;
-        GitHubConfig github = 9;
-        JiraConfig jira = 10;
-        ConfluenceConfig confluence = 11;
-        SalesforceConfig salesforce = 12;
-        DropboxAccessTokenConfig dropboxAccessToken = 13;
-        DropboxUsernamePasswordConfig dropboxUsernamePassword = 14;
-        HttpHeadersConfig httpHeaders = 15;
-        SecretConfig secret = 99;
-        ErrorConfig error = 9999;
-    }
+  oneof config {
+    S3Config s3 = 1;
+    MySqlConfig mysql = 2;
+    OracleConfig oracle = 3;
+    PostgreSQLConfig postgresql = 4;
+    SQLServerConfig sqlserver = 5;
+    SnowflakeConfig snowflake = 6;
+    SqliteConfig sqlite = 7;
+    TeradataConfig teradata = 8;
+    GitHubConfig github = 9;
+    JiraConfig jira = 10;
+    ConfluenceConfig confluence = 11;
+    SalesforceConfig salesforce = 12;
+    DropboxAccessTokenConfig dropboxAccessToken = 13;
+    DropboxUsernamePasswordConfig dropboxUsernamePassword = 14;
+    HttpHeadersConfig httpHeaders = 15;
+    SecretConfig secret = 99;
+    ErrorConfig error = 9999;
+  }
 }
 
 message S3Config {
-    optional S3AccessSecretKey accessSecretKey = 1;
-    optional string region = 2;
+  optional S3AccessSecretKey accessSecretKey = 1;
+  optional string region = 2;
 }
 
 message S3AccessSecretKey {
-    string accessKey = 1;
-    string secretKey = 2;
+  string accessKey = 1;
+  string secretKey = 2;
 }
 
 message MySqlConfig {
-    string host = 1;
-    int32 port = 2;
-    string database = 3;
-    string user = 4;
-    string password = 5;
+  string host = 1;
+  int32 port = 2;
+  string database = 3;
+  string user = 4;
+  string password = 5;
 }
 
 message OracleConfig {
-    string host = 1;
-    int32 port = 2;
-    string database = 3;
-    string user = 4;
-    string password = 5;
-    optional string schema = 6;
+  string host = 1;
+  int32 port = 2;
+  string database = 3;
+  string user = 4;
+  string password = 5;
+  optional string schema = 6;
 }
 
 message PostgreSQLConfig {
-    string host = 1;
-    int32 port = 2;
-    string database = 3;
-    string user = 4;
-    string password = 5;
-    optional string schema = 6;
+  string host = 1;
+  int32 port = 2;
+  string database = 3;
+  string user = 4;
+  string password = 5;
+  optional string schema = 6;
 }
 
 message SQLServerConfig {
-    string host = 1;
-    int32 port = 2;
-    string database = 3;
-    string user = 4;
-    string password = 5;
-    optional string schema = 6;
+  string host = 1;
+  int32 port = 2;
+  string database = 3;
+  string user = 4;
+  string password = 5;
+  optional string schema = 6;
 }
 
 message SnowflakeConfig {
-    string database = 1;
-    string user = 2;
-    string password = 3;
-    string accountIdentifier = 4;
-    map<string, string> parameters = 5;
-    optional string schema = 6;
+  string database = 1;
+  string user = 2;
+  string password = 3;
+  string accountIdentifier = 4;
+  map<string, string> parameters = 5;
+  optional string schema = 6;
 }
 
 message SqliteConfig {
-    string path = 1;
-    optional string schema = 2;
+  string path = 1;
+  optional string schema = 2;
 }
 
 message TeradataConfig {
-    string host = 1;
-    int32 port = 2;
-    string database = 3;
-    string user = 4;
-    string password = 5;
-    map<string, string> parameters = 6;
-    optional string schema = 7;
+  string host = 1;
+  int32 port = 2;
+  string database = 3;
+  string user = 4;
+  string password = 5;
+  map<string, string> parameters = 6;
+  optional string schema = 7;
 }
 
 message GitHubConfig {
-    string token = 1;
-    optional string baseUrl = 2;
+  string token = 1;
+  optional string baseUrl = 2;
 }
 
 message JiraConfig {
-    string baseUrl = 1;
-    string username = 2;
-    string token = 3;
-    JiraTokenType tokenType = 4;
-}
+  string baseUrl = 1;
+  string username = 2;
+  string token = 3;
+  JiraTokenType tokenType = 4;
 
-enum JiraTokenType {
+  enum JiraTokenType {
     STANDARD_ACCESS_TOKEN = 0;
     PERSONAL_ACCESS_TOKEN = 1;
+  }
 }
 
 message ConfluenceConfig {
-    string baseUrl = 1;
-    string username = 2;
-    string token = 3;
+  string baseUrl = 1;
+  string username = 2;
+  string token = 3;
 }
 
 message SalesforceConfig {
-    string url = 1;
-    string username = 2;
-    string password = 3;
-    string securityToken = 4;
-    string clientId = 5;
-    string apiVersion = 6;
-    repeated string customObjects = 7;
+  string url = 1;
+  string username = 2;
+  string password = 3;
+  string securityToken = 4;
+  string clientId = 5;
+  string apiVersion = 6;
+  repeated string customObjects = 7;
 }
 
 message DropboxAccessTokenConfig {
-    string accessToken = 1;
+  string accessToken = 1;
 }
 
 message DropboxUsernamePasswordConfig {
-    string username = 1;
-    string password = 2;
+  string username = 1;
+  string password = 2;
 }
 
 message HttpHeadersConfig {
-    map<string, string> headers = 1;
+  map<string, string> headers = 1;
 }
 
 // This is not used in practice but is kept for compatibility with FDW interface.
 message SecretConfig {
-    string name = 1;
-    string value = 2;
+  string name = 1;
+  string value = 2;
 }
 
 message ErrorConfig {
-    string message = 1;
+  string message = 1;
 }
\ No newline at end of file
diff --git a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/messages.proto b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/messages.proto
index 14c746b5b..cd4effd2a 100644
--- a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/messages.proto
+++ b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/messages.proto
@@ -20,7 +20,10 @@ package com.rawlabs.protocol.compiler;
 message Message {
   string message = 1;
   repeated Range positions = 2;
-  optional string code = 3;
+  string code = 3;
+  repeated int32 tags = 4;
+  Severity severity = 5;
+
   enum Severity {
     HINT = 0;
     INFO = 10;
diff --git a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/program_environment.proto b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/program_environment.proto
index 4e8fc78f6..412353f4b 100644
--- a/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/program_environment.proto
+++ b/protocol-compiler/src/main/protobuf/com/rawlabs/protocol/compiler/program_environment.proto
@@ -17,6 +17,7 @@ option java_multiple_files = true;
 
 package com.rawlabs.protocol.compiler;
 
+import "com/rawlabs/protocol/raw/values.proto";
 import "com/rawlabs/protocol/compiler/location_config.proto";
 
 message ProgramEnvironment {
@@ -36,5 +37,5 @@ message Arguments {
 
 message Argument {
   string name = 1;
-  string value = 2;
+  com.rawlabs.protocol.raw.Value value = 2;
 }
\ No newline at end of file