diff --git a/src/main/scala/handlers/AstroHandler.scala b/src/main/scala/handlers/AstroHandler.scala
index 2d8d634..b2fe0af 100644
--- a/src/main/scala/handlers/AstroHandler.scala
+++ b/src/main/scala/handlers/AstroHandler.scala
@@ -27,7 +27,7 @@ class AstroHandler extends FileHandler:
     */
   override def generateLicense(raw: String): String =
     val body = raw.linesIterator.mkString("\n")
-    s"\n<!--\n$body\n-->\n"
+    s"<!--\n$body\n-->\n"
 
   /** Add a license header after frontmatter if present. */
   override def addLicense(fileDump: String, licenseText: String): (String, Boolean) =
@@ -42,16 +42,19 @@ class AstroHandler extends FileHandler:
     val lines         = splitLines(fileDump)
     val insertAt      = frontmatterInsertIndex(lines)
     val expectedFirst = rendered.linesIterator.nextOption.getOrElse("")
-    val actualFirst   = lines.lift(insertAt).getOrElse("")
+    val actualFirst   = lines.drop(insertAt).dropWhile(_.trim.isEmpty).headOption.getOrElse("")
     if expectedFirst == actualFirst then LicenseState.Present
     else if hasExternalAt(lines, insertAt) then LicenseState.External
     else LicenseState.Missing
 
   private def insertAfterFrontmatter(fileDump: String, rendered: String): String =
-    val lines        = splitLines(fileDump)
-    val insertAt     = frontmatterInsertIndex(lines)
-    val headerLines  = splitLines(rendered.stripSuffix("\n"))
-    val updatedLines = lines.patch(insertAt, headerLines, 0)
+    val lines           = splitLines(fileDump)
+    val insertAt        = frontmatterInsertIndex(lines)
+    val trimmedInsertAt = skipBlankLines(lines, insertAt)
+    val headerLines     = splitLines(rendered.stripSuffix("\n"))
+    val separator       = if insertAt > 0 then Vector("") else Vector.empty
+    val updatedLines    =
+      lines.patch(insertAt, separator ++ headerLines, trimmedInsertAt - insertAt)
     updatedLines.mkString("\n")
 
   private def frontmatterInsertIndex(lines: Vector[String]): Int =
@@ -66,7 +69,8 @@ class AstroHandler extends FileHandler:
       externalMarkers: Vector[String] = Vector("Copyright", "SPDX-License-Identifier"),
       scanLines: Int = 3
   ): Boolean =
-    val headerLines = lines.drop(insertAt).take(scanLines).map(_.trim)
+    val headerLines =
+      lines.drop(insertAt).dropWhile(_.trim.isEmpty).take(scanLines).map(_.trim)
     externalMarkers.exists(marker => headerLines.exists(_.contains(marker)))
 
   private def splitLines(text: String): Vector[String] =
@@ -74,3 +78,8 @@ class AstroHandler extends FileHandler:
       .split("\n", -1)
       .toVector
       .map(line => if line.endsWith("\r") then line.dropRight(1) else line)
+
+  private def skipBlankLines(lines: Vector[String], startAt: Int): Int =
+    var idx = startAt
+    while idx < lines.length && lines(idx).trim.isEmpty do idx += 1
+    idx
diff --git a/src/main/scala/handlers/MdxHandler.scala b/src/main/scala/handlers/MdxHandler.scala
index 2ca4139..7b39b91 100644
--- a/src/main/scala/handlers/MdxHandler.scala
+++ b/src/main/scala/handlers/MdxHandler.scala
@@ -27,7 +27,7 @@ class MdxHandler extends FileHandler:
     */
   override def generateLicense(raw: String): String =
     val body = raw.linesIterator.mkString("\n")
-    s"\n{/*\n$body\n*/}\n"
+    s"{/*\n$body\n*/}\n"
 
   /** Add a license header after frontmatter if present. */
   override def addLicense(fileDump: String, licenseText: String): (String, Boolean) =
@@ -42,16 +42,19 @@ class MdxHandler extends FileHandler:
     val lines         = splitLines(fileDump)
     val insertAt      = frontmatterInsertIndex(lines)
     val expectedFirst = rendered.linesIterator.nextOption.getOrElse("")
-    val actualFirst   = lines.lift(insertAt).getOrElse("")
+    val actualFirst   = lines.drop(insertAt).dropWhile(_.trim.isEmpty).headOption.getOrElse("")
     if expectedFirst == actualFirst then LicenseState.Present
     else if hasExternalAt(lines, insertAt) then LicenseState.External
     else LicenseState.Missing
 
   private def insertAfterFrontmatter(fileDump: String, rendered: String): String =
-    val lines        = splitLines(fileDump)
-    val insertAt     = frontmatterInsertIndex(lines)
-    val headerLines  = splitLines(rendered.stripSuffix("\n"))
-    val updatedLines = lines.patch(insertAt, headerLines, 0)
+    val lines           = splitLines(fileDump)
+    val insertAt        = frontmatterInsertIndex(lines)
+    val trimmedInsertAt = skipBlankLines(lines, insertAt)
+    val headerLines     = splitLines(rendered.stripSuffix("\n"))
+    val separator       = if insertAt > 0 then Vector("") else Vector.empty
+    val updatedLines    =
+      lines.patch(insertAt, separator ++ headerLines, trimmedInsertAt - insertAt)
     updatedLines.mkString("\n")
 
   private def frontmatterInsertIndex(lines: Vector[String]): Int =
@@ -66,7 +69,8 @@ class MdxHandler extends FileHandler:
       externalMarkers: Vector[String] = Vector("Copyright", "SPDX-License-Identifier"),
       scanLines: Int = 3
   ): Boolean =
-    val headerLines = lines.drop(insertAt).take(scanLines).map(_.trim)
+    val headerLines =
+      lines.drop(insertAt).dropWhile(_.trim.isEmpty).take(scanLines).map(_.trim)
     externalMarkers.exists(marker => headerLines.exists(_.contains(marker)))
 
   private def splitLines(text: String): Vector[String] =
@@ -74,3 +78,8 @@ class MdxHandler extends FileHandler:
       .split("\n", -1)
       .toVector
       .map(line => if line.endsWith("\r") then line.dropRight(1) else line)
+
+  private def skipBlankLines(lines: Vector[String], startAt: Int): Int =
+    var idx = startAt
+    while idx < lines.length && lines(idx).trim.isEmpty do idx += 1
+    idx
diff --git a/src/test/resources/cases/check-astro-mdx-blank-line/case.yaml b/src/test/resources/cases/check-astro-mdx-blank-line/case.yaml
new file mode 100644
index 0000000..c284b39
--- /dev/null
+++ b/src/test/resources/cases/check-astro-mdx-blank-line/case.yaml
@@ -0,0 +1,10 @@
+name: check-astro-mdx-blank-line
+command: check
+args:
+  - "source/*"
+ignore: []
+expectExit: 1
+expectedOutput:
+  - "Missing: source/one.astro"
+  - "Missing: source/one.mdx"
+  - "Skipped: 0"
diff --git a/src/test/resources/cases/check-astro-mdx-blank-line/config.yaml b/src/test/resources/cases/check-astro-mdx-blank-line/config.yaml
new file mode 100644
index 0000000..b66ce4d
--- /dev/null
+++ b/src/test/resources/cases/check-astro-mdx-blank-line/config.yaml
@@ -0,0 +1,3 @@
+holder: NiceBots.xyz
+spdx: MIT
+year: 2026
diff --git a/src/test/resources/cases/check-astro-mdx-blank-line/source/one.astro b/src/test/resources/cases/check-astro-mdx-blank-line/source/one.astro
new file mode 100644
index 0000000..68c20d8
--- /dev/null
+++ b/src/test/resources/cases/check-astro-mdx-blank-line/source/one.astro
@@ -0,0 +1,5 @@
+---
+title: Hello
+---
+
+<div>Hi</div>
diff --git a/src/test/resources/cases/check-astro-mdx-blank-line/source/one.mdx b/src/test/resources/cases/check-astro-mdx-blank-line/source/one.mdx
new file mode 100644
index 0000000..3690192
--- /dev/null
+++ b/src/test/resources/cases/check-astro-mdx-blank-line/source/one.mdx
@@ -0,0 +1,5 @@
+---
+title: Hello
+---
+
+# Hello
diff --git a/src/test/resources/cases/index.txt b/src/test/resources/cases/index.txt
index 9f2dd50..2b1869a 100644
--- a/src/test/resources/cases/index.txt
+++ b/src/test/resources/cases/index.txt
@@ -14,3 +14,4 @@ check-external
 check-missing
 check-mixed
 check-with-ignore
+check-astro-mdx-blank-line