diff --git a/README.md b/README.md
index 68f895c..2bec353 100644
--- a/README.md
+++ b/README.md
@@ -15,4 +15,5 @@ This extensions requires the [starlark language extension](https://github.com/ph
 
 ## Known Issues
 
-Theme overlap between starlark and yaml highlighting.
+Multi-line function calls result in all following annotations being matched as
+starlark comments.
diff --git a/images/syntax-highlighting.png b/images/syntax-highlighting.png
index 7a87818..b00b5e7 100644
Binary files a/images/syntax-highlighting.png and b/images/syntax-highlighting.png differ
diff --git a/language-configuration.json b/language-configuration.json
index 8f162a0..6fe158e 100644
--- a/language-configuration.json
+++ b/language-configuration.json
@@ -1,30 +1,79 @@
 {
     "comments": {
         // symbol used for single line comment. Remove this entry if your language does not support line comments
-        "lineComment": "//",
-        // symbols used for start and end a block comment. Remove this entry if your language does not support block comments
-        "blockComment": [ "/*", "*/" ]
+        "lineComment": "#!",
     },
     // symbols used as brackets
     "brackets": [
-        ["{", "}"],
-        ["[", "]"],
-        ["(", ")"]
+        [
+            "{",
+            "}"
+        ],
+        [
+            "[",
+            "]"
+        ],
+        [
+            "(",
+            ")"
+        ],
+        [
+            "if",
+            "end"
+        ],
+        [
+            "def",
+            "end"
+        ],
+        [
+            "for",
+            "end"
+        ]
     ],
     // symbols that are auto closed when typing
     "autoClosingPairs": [
-        ["{", "}"],
-        ["[", "]"],
-        ["(", ")"],
-        ["\"", "\""],
-        ["'", "'"]
+        [
+            "{",
+            "}"
+        ],
+        [
+            "[",
+            "]"
+        ],
+        [
+            "(",
+            ")"
+        ],
+        [
+            "\"",
+            "\""
+        ],
+        [
+            "'",
+            "'"
+        ]
     ],
     // symbols that can be used to surround a selection
     "surroundingPairs": [
-        ["{", "}"],
-        ["[", "]"],
-        ["(", ")"],
-        ["\"", "\""],
-        ["'", "'"]
+        [
+            "{",
+            "}"
+        ],
+        [
+            "[",
+            "]"
+        ],
+        [
+            "(",
+            ")"
+        ],
+        [
+            "\"",
+            "\""
+        ],
+        [
+            "'",
+            "'"
+        ]
     ]
-}
\ No newline at end of file
+}
diff --git a/package.json b/package.json
index 22d2be2..f764d94 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
     "name": "vscode-ytt",
     "displayName": "vscode-ytt",
     "description": "Syntax highlighting for ytt",
-    "version": "0.0.2",
+    "version": "0.0.3",
     "publisher": "ewrenn",
     "repository": {
         "type": "git",
@@ -18,9 +18,22 @@
         "Programming Languages"
     ],
     "contributes": {
+        "languages": [
+            {
+                "id": "ytt",
+                "extensions": [
+                    ".yaml",
+                    ".yml"
+                ],
+                "aliases": [
+                    "ytt"
+                ],
+                "configuration": "./language-configuration.json"
+            }
+        ],
         "grammars": [
             {
-                "language": "yaml",
+                "language": "ytt",
                 "scopeName": "source.yaml.ytt",
                 "path": "./syntaxes/ytt.tmLanguage.json"
             }
diff --git a/syntaxes/ytt.tmLanguage.json b/syntaxes/ytt.tmLanguage.json
index 45bcd61..7bd128c 100644
--- a/syntaxes/ytt.tmLanguage.json
+++ b/syntaxes/ytt.tmLanguage.json
@@ -41,14 +41,23 @@
 			"name": "comment.line.number-sign.ytt"
 		},
 		"ytt-annotation": {
-			"begin": "#@",
+			"begin": "#@\\S*",
 			"beginCaptures": {
 				"0": {
-					"name": "keyword.control.flow.ytt"
+					"name": "support.class.ytt"
 				}
 			},
 			"end": "\\n",
 			"patterns": [
+				{
+					"include": "#ytt-combo-end"
+				},
+				{
+					"include": "#ytt-end"
+				},
+				{
+					"include": "#ytt-def"
+				},
 				{
 					"include": "source.starlark"
 				}
@@ -63,6 +72,18 @@
 			},
 			"end": "\\n",
 			"name": "comment.line.number-sign"
+		},
+		"ytt-combo-end": {
+			"match": "(for|if|def)\/end",
+			"name": "keyword.control.flow.ytt"
+		},
+		"ytt-end": {
+			"match": "\\s+end$",
+			"name": "keyword.control.flow.ytt"
+		},
+		"ytt-def": {
+			"match":  "\\s*\\b(def)\\s+(?=[[:alpha:]_][[:word:]]*\\s*\\()",
+			"name": "keyword.control.flow.ytt"
 		}
 	},
 	"scopeName": "source.yaml.ytt"