diff --git a/internal/api/markdown.go b/internal/api/markdown.go
index 5f1e495..b808ce4 100644
--- a/internal/api/markdown.go
+++ b/internal/api/markdown.go
@@ -463,6 +463,31 @@ func countLeadingSpaces(line string) int {
 	return count
 }
 
+// hasCodeMark returns true if the content node has an inline code mark.
+// In ADF, the code mark is exclusive and cannot be combined with other marks
+// like strong, em, or strike. Jira will reject the document with INVALID_INPUT.
+func hasCodeMark(c ADFContent) bool {
+	for _, m := range c.Marks {
+		if m.Type == "code" {
+			return true
+		}
+	}
+	return false
+}
+
+// addMarkToContent prepends a mark to inner content nodes, skipping nodes that
+// already have a code mark (since code is exclusive in ADF).
+func addMarkToContent(innerContent []ADFContent, mark ADFMark) []ADFContent {
+	result := make([]ADFContent, 0, len(innerContent))
+	for _, c := range innerContent {
+		if !hasCodeMark(c) {
+			c.Marks = append([]ADFMark{mark}, c.Marks...)
+		}
+		result = append(result, c)
+	}
+	return result
+}
+
 // parseInline parses inline markdown elements (bold, italic, code, links).
 func parseInline(text string) []ADFContent {
 	if text == "" {
@@ -519,20 +544,14 @@ func parseInline(text string) []ADFContent {
 		if boldMatch := regexp.MustCompile(`^\*\*([^*]+)\*\*`).FindStringSubmatch(remaining); len(boldMatch) > 0 {
 			// Parse inner content for nested formatting
 			innerContent := parseInline(boldMatch[1])
-			for _, c := range innerContent {
-				c.Marks = append([]ADFMark{{Type: "strong"}}, c.Marks...)
-				content = append(content, c)
-			}
+			content = append(content, addMarkToContent(innerContent, ADFMark{Type: "strong"})...)
 			remaining = remaining[len(boldMatch[0]):]
 			matched = true
 			continue
 		}
 		if boldMatch := regexp.MustCompile(`^__([^_]+)__`).FindStringSubmatch(remaining); len(boldMatch) > 0 {
 			innerContent := parseInline(boldMatch[1])
-			for _, c := range innerContent {
-				c.Marks = append([]ADFMark{{Type: "strong"}}, c.Marks...)
-				content = append(content, c)
-			}
+			content = append(content, addMarkToContent(innerContent, ADFMark{Type: "strong"})...)
 			remaining = remaining[len(boldMatch[0]):]
 			matched = true
 			continue
@@ -541,10 +560,7 @@ func parseInline(text string) []ADFContent {
 		// Strikethrough: ~~text~~
 		if strikeMatch := regexp.MustCompile(`^~~([^~]+)~~`).FindStringSubmatch(remaining); len(strikeMatch) > 0 {
 			innerContent := parseInline(strikeMatch[1])
-			for _, c := range innerContent {
-				c.Marks = append([]ADFMark{{Type: "strike"}}, c.Marks...)
-				content = append(content, c)
-			}
+			content = append(content, addMarkToContent(innerContent, ADFMark{Type: "strike"})...)
 			remaining = remaining[len(strikeMatch[0]):]
 			matched = true
 			continue
@@ -553,20 +569,14 @@ func parseInline(text string) []ADFContent {
 		// Italic: *text* or _text_ (must not be followed by another * or _)
 		if italicMatch := regexp.MustCompile(`^\*([^*]+)\*`).FindStringSubmatch(remaining); len(italicMatch) > 0 {
 			innerContent := parseInline(italicMatch[1])
-			for _, c := range innerContent {
-				c.Marks = append([]ADFMark{{Type: "em"}}, c.Marks...)
-				content = append(content, c)
-			}
+			content = append(content, addMarkToContent(innerContent, ADFMark{Type: "em"})...)
 			remaining = remaining[len(italicMatch[0]):]
 			matched = true
 			continue
 		}
 		if italicMatch := regexp.MustCompile(`^_([^_]+)_`).FindStringSubmatch(remaining); len(italicMatch) > 0 {
 			innerContent := parseInline(italicMatch[1])
-			for _, c := range innerContent {
-				c.Marks = append([]ADFMark{{Type: "em"}}, c.Marks...)
-				content = append(content, c)
-			}
+			content = append(content, addMarkToContent(innerContent, ADFMark{Type: "em"})...)
 			remaining = remaining[len(italicMatch[0]):]
 			matched = true
 			continue
diff --git a/internal/api/markdown_code_mark_test.go b/internal/api/markdown_code_mark_test.go
new file mode 100644
index 0000000..ebe0153
--- /dev/null
+++ b/internal/api/markdown_code_mark_test.go
@@ -0,0 +1,98 @@
+package api
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestMarkdownToADF_CodeInsideBold(t *testing.T) {
+	adf := MarkdownToADF("**Bold with `code` inside**")
+
+	if len(adf.Content) != 1 {
+		t.Fatalf("expected 1 block, got %d", len(adf.Content))
+	}
+
+	para := adf.Content[0]
+	if para.Type != "paragraph" {
+		t.Fatalf("expected paragraph, got %s", para.Type)
+	}
+
+	if len(para.Content) != 3 {
+		b, _ := json.MarshalIndent(adf, "", "  ")
+		t.Fatalf("expected 3 inline nodes, got %d:\n%s", len(para.Content), b)
+	}
+
+	// "Bold with " should have strong mark
+	if para.Content[0].Text != "Bold with " {
+		t.Errorf("expected 'Bold with ', got %q", para.Content[0].Text)
+	}
+	if len(para.Content[0].Marks) != 1 || para.Content[0].Marks[0].Type != "strong" {
+		t.Errorf("expected [strong] marks, got %v", para.Content[0].Marks)
+	}
+
+	// "code" should have ONLY code mark (not strong+code)
+	if para.Content[1].Text != "code" {
+		t.Errorf("expected 'code', got %q", para.Content[1].Text)
+	}
+	if len(para.Content[1].Marks) != 1 || para.Content[1].Marks[0].Type != "code" {
+		t.Errorf("expected [code] marks only, got %v", para.Content[1].Marks)
+	}
+
+	// " inside" should have strong mark
+	if para.Content[2].Text != " inside" {
+		t.Errorf("expected ' inside', got %q", para.Content[2].Text)
+	}
+	if len(para.Content[2].Marks) != 1 || para.Content[2].Marks[0].Type != "strong" {
+		t.Errorf("expected [strong] marks, got %v", para.Content[2].Marks)
+	}
+}
+
+func TestMarkdownToADF_CodeInsideItalic(t *testing.T) {
+	adf := MarkdownToADF("*italic `code` here*")
+
+	para := adf.Content[0]
+	for _, c := range para.Content {
+		if hasCodeMark(c) {
+			if len(c.Marks) != 1 {
+				t.Errorf("code node should have only code mark, got %v", c.Marks)
+			}
+		}
+	}
+}
+
+func TestMarkdownToADF_CodeInsideStrikethrough(t *testing.T) {
+	adf := MarkdownToADF("~~deleted `code` here~~")
+
+	para := adf.Content[0]
+	for _, c := range para.Content {
+		if hasCodeMark(c) {
+			if len(c.Marks) != 1 {
+				t.Errorf("code node should have only code mark, got %v", c.Marks)
+			}
+		}
+	}
+}
+
+func TestMarkdownToADF_BoldWithCodeAndCodeBlock(t *testing.T) {
+	// This was the exact combination that caused INVALID_INPUT from Jira
+	md := "**Migration: Falsche `s_action` korrigieren**\n\n```sql\nSELECT 1\n```"
+	adf := MarkdownToADF(md)
+
+	if len(adf.Content) != 2 {
+		b, _ := json.MarshalIndent(adf, "", "  ")
+		t.Fatalf("expected 2 blocks (paragraph + codeBlock), got %d:\n%s", len(adf.Content), b)
+	}
+
+	// Verify no code node has additional marks
+	para := adf.Content[0]
+	for _, c := range para.Content {
+		if hasCodeMark(c) && len(c.Marks) > 1 {
+			t.Errorf("code node should have only code mark, got %v", c.Marks)
+		}
+	}
+
+	// Verify code block is present
+	if adf.Content[1].Type != "codeBlock" {
+		t.Errorf("expected codeBlock, got %s", adf.Content[1].Type)
+	}
+}