diff --git a/TODO.md b/TODO.md
index f3e5025..e69de29 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1 +0,0 @@
-[docs] syntax design
diff --git a/docs/diary/2023-11-10-syntax-design.md b/docs/diary/2023-11-10-syntax-design.md
index a3043d3..e15c263 100644
--- a/docs/diary/2023-11-10-syntax-design.md
+++ b/docs/diary/2023-11-10-syntax-design.md
@@ -5,3 +5,31 @@ date: 2023-11-10
 ---
 
 The syntax should be optimized for sequential routing (the most used use case).
+
+The main idea is to use function application to build nets (just like iNet).
+A transition has both input and output, thus we can not just use `f(x, y)`,
+I decide to use something like the following ASCII art like syntax
+for transition application:
+
+```
+(inputArg, ...) -> [transition] -> (outputArg, ...)
+```
+
+```
+transition processComplaint(
+  place input: Complaint
+  ------------------------
+  place output: ComplaintArchive
+) {
+  (input) -> [register] -> (c1, c2)
+  (c1) -> [sendQuestionnaire] -> (c3)
+  (c3) -> [processQuestionnaire] -> (c5)
+  (c3) -> [timeout] -> (c5)
+
+  (c5, c6) -> [archive] -> (output)
+
+  (c2) -> <evaluate> -> (c6, c7)
+  (c5, c7) -> [processComplaint] -> (c5, c8)
+  (c8) -> <checkProcessing> -> (c6, c7)
+}
+```