diff --git a/.changeset/some-loops-matter.md b/.changeset/some-loops-matter.md
new file mode 100644
index 00000000..02019347
--- /dev/null
+++ b/.changeset/some-loops-matter.md
@@ -0,0 +1,5 @@
+---
+"@effect/language-service": patch
+---
+
+Include start and end in json diagnostics command
diff --git a/packages/language-service/src/cli/diagnostics.ts b/packages/language-service/src/cli/diagnostics.ts
index c5ee97b7..f50ddbac 100644
--- a/packages/language-service/src/cli/diagnostics.ts
+++ b/packages/language-service/src/cli/diagnostics.ts
@@ -51,6 +51,8 @@ interface JsonFormattedDiagnostic {
   column: number
   endLine: number
   endColumn: number
+  start: number
+  length: number
   severity: SeverityLevel
   code: number
   name: string
@@ -107,6 +109,8 @@ const formatDiagnosticForJson = (
 
   return {
     file: diagnostic.file.fileName,
+    start: diagnostic.start,
+    length: diagnostic.length ?? 0,
     line: line + 1,
     column: character + 1,
     endLine: endLine + 1,