diff --git a/examples/gno.land/r/nt/boards2/public.gno b/examples/gno.land/r/nt/boards2/public.gno
index 06505b4a2fc..cc2e36279f5 100644
--- a/examples/gno.land/r/nt/boards2/public.gno
+++ b/examples/gno.land/r/nt/boards2/public.gno
@@ -92,6 +92,9 @@ func CreateThread(bid BoardID, title, body string) PostID {
 func CreateReply(bid BoardID, threadID, replyID PostID, body string) PostID {
 	assertIsUserCall()
 
+	body = strings.TrimSpace(body)
+	assertBodyIsNotEmpty(body)
+
 	caller := std.GetOrigCaller()
 	board := mustGetBoard(bid)
 	assertHasBoardPermission(board, caller, PermissionReplyCreate)
@@ -100,7 +103,7 @@ func CreateReply(bid BoardID, threadID, replyID PostID, body string) PostID {
 	assertThreadVisible(thread)
 
 	var reply *Post
-	if replyID == threadID {
+	if replyID == 0 {
 		// When the parent reply is the thread just add reply to thread
 		reply = thread.AddReply(caller, body)
 	} else {
diff --git a/examples/gno.land/r/nt/boards2/z_2_a_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_a_filetest.gno
index c4fd1da0c87..f9e332d2cca 100644
--- a/examples/gno.land/r/nt/boards2/z_2_a_filetest.gno
+++ b/examples/gno.land/r/nt/boards2/z_2_a_filetest.gno
@@ -2,22 +2,39 @@ package main
 
 import (
 	"std"
+	"strings"
 
 	"gno.land/r/nt/boards2"
 )
 
-const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+const (
+	owner   = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+	path    = "test-board/1/2"
+	comment = "Test comment"
+)
+
+var (
+	bid boards2.BoardID
+	tid boards2.PostID
+)
 
 func init() {
 	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test-board")
+	tid = boards2.CreateThread(bid, "Foo", "bar")
 }
 
 func main() {
-	bid := boards2.CreateBoard("test123")
-	pid := boards2.CreateThread(bid, "thread", "thread")
-	boards2.FlagThread(bid, pid, "reason")
-	_ = boards2.CreateReply(bid, pid, pid, "reply")
+	rid := boards2.CreateReply(bid, tid, 0, comment)
+
+	// Ensure that returned ID is right
+	println(rid == 2)
+
+	// Render content must contain the reply
+	content := boards2.Render(path)
+	println(strings.Contains(content, "\n> "+comment+"\n"))
 }
 
-// Error:
-// thread with ID: 1 was hidden
+// Output:
+// true
+// true
diff --git a/examples/gno.land/r/nt/boards2/z_2_b_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_b_filetest.gno
index f215c0c84eb..88b2233dff3 100644
--- a/examples/gno.land/r/nt/boards2/z_2_b_filetest.gno
+++ b/examples/gno.land/r/nt/boards2/z_2_b_filetest.gno
@@ -13,14 +13,8 @@ func init() {
 }
 
 func main() {
-	// ensure that nested replies denied if root thread is hidden.
-	bid := boards2.CreateBoard("test123")
-	pid := boards2.CreateThread(bid, "thread", "thread")
-	rid := boards2.CreateReply(bid, pid, pid, "reply1")
-
-	boards2.FlagThread(bid, pid, "reason")
-	_ = boards2.CreateReply(bid, pid, rid, "reply1.1")
+	boards2.CreateReply(404, 1, 0, "comment")
 }
 
 // Error:
-// thread with ID: 1 was hidden
+// board does not exist with ID: 404
diff --git a/examples/gno.land/r/nt/boards2/z_2_c_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_c_filetest.gno
index 98ffbc7f624..4e0779194ab 100644
--- a/examples/gno.land/r/nt/boards2/z_2_c_filetest.gno
+++ b/examples/gno.land/r/nt/boards2/z_2_c_filetest.gno
@@ -8,19 +8,16 @@ import (
 
 const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
 
+var bid boards2.BoardID
+
 func init() {
 	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test123")
 }
 
 func main() {
-	// ensure that nested replies denied if root thread is hidden.
-	bid := boards2.CreateBoard("test123")
-	pid := boards2.CreateThread(bid, "thread", "thread")
-	rid := boards2.CreateReply(bid, pid, pid, "reply1")
-
-	boards2.FlagReply(bid, pid, rid, "reason")
-	_ = boards2.CreateReply(bid, pid, rid, "reply1.1")
+	boards2.CreateReply(bid, 404, 0, "comment")
 }
 
 // Error:
-// reply with ID: 2 was hidden
+// thread does not exist with ID: 404
diff --git a/examples/gno.land/r/nt/boards2/z_2_d_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_d_filetest.gno
index 9a95fd869b7..66edfb3d6f2 100644
--- a/examples/gno.land/r/nt/boards2/z_2_d_filetest.gno
+++ b/examples/gno.land/r/nt/boards2/z_2_d_filetest.gno
@@ -8,18 +8,20 @@ import (
 
 const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
 
+var (
+	bid boards2.BoardID
+	tid boards2.PostID
+)
+
 func init() {
 	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test-board")
+	tid = boards2.CreateThread(bid, "Foo", "bar")
 }
 
 func main() {
-	// Only single user per flag can't be tested atm, as flagThreshold = 1.
-	bid := boards2.CreateBoard("test123")
-	pid := boards2.CreateThread(bid, "thread", "thread")
-
-	boards2.FlagThread(bid, pid, "reason1")
-	boards2.FlagThread(bid, pid, "reason2")
+	boards2.CreateReply(bid, tid, 404, "comment")
 }
 
 // Error:
-// item flag count threshold exceeded: 1
+// reply does not exist with ID: 404
diff --git a/examples/gno.land/r/nt/boards2/z_2_e_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_e_filetest.gno
new file mode 100644
index 00000000000..8c231b552cd
--- /dev/null
+++ b/examples/gno.land/r/nt/boards2/z_2_e_filetest.gno
@@ -0,0 +1,30 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/nt/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+var (
+	bid boards2.BoardID
+	tid boards2.PostID
+)
+
+func init() {
+	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test123")
+	tid = boards2.CreateThread(bid, "Foo", "bar")
+
+	// Hide thread by flagging it so reply can't be submitted
+	boards2.FlagThread(bid, tid, "reason")
+}
+
+func main() {
+	boards2.CreateReply(bid, tid, 0, "Test reply")
+}
+
+// Error:
+// thread with ID: 1 was hidden
diff --git a/examples/gno.land/r/nt/boards2/z_2_f_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_f_filetest.gno
new file mode 100644
index 00000000000..0b595a84cb6
--- /dev/null
+++ b/examples/gno.land/r/nt/boards2/z_2_f_filetest.gno
@@ -0,0 +1,31 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/nt/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+var (
+	bid      boards2.BoardID
+	tid, rid boards2.PostID
+)
+
+func init() {
+	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test123")
+	tid = boards2.CreateThread(bid, "Foo", "bar")
+	rid = boards2.CreateReply(bid, tid, 0, "reply1")
+
+	// Hide thread by flagging it so reply of a reply can't be submitted
+	boards2.FlagThread(bid, tid, "reason")
+}
+
+func main() {
+	boards2.CreateReply(bid, tid, rid, "reply1.1")
+}
+
+// Error:
+// thread with ID: 1 was hidden
diff --git a/examples/gno.land/r/nt/boards2/z_2_g_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_g_filetest.gno
new file mode 100644
index 00000000000..6f69a023a0b
--- /dev/null
+++ b/examples/gno.land/r/nt/boards2/z_2_g_filetest.gno
@@ -0,0 +1,31 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/nt/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+var (
+	bid      boards2.BoardID
+	tid, rid boards2.PostID
+)
+
+func init() {
+	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test123")
+	tid = boards2.CreateThread(bid, "thread", "thread")
+	rid = boards2.CreateReply(bid, tid, 0, "reply1")
+
+	// Hide reply by flagging it so sub reply can't be submitted
+	boards2.FlagReply(bid, tid, rid, "reason")
+}
+
+func main() {
+	boards2.CreateReply(bid, tid, rid, "reply1.1")
+}
+
+// Error:
+// reply with ID: 2 was hidden
diff --git a/examples/gno.land/r/nt/boards2/z_2_h_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_h_filetest.gno
new file mode 100644
index 00000000000..e34d8d167ef
--- /dev/null
+++ b/examples/gno.land/r/nt/boards2/z_2_h_filetest.gno
@@ -0,0 +1,32 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/nt/boards2"
+)
+
+const (
+	owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+	user  = std.Address("g1us8428u2a5satrlxzagqqa5m6vmuze025anjlj") // @test2
+)
+
+var (
+	bid boards2.BoardID
+	tid boards2.PostID
+)
+
+func init() {
+	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test123")
+	tid = boards2.CreateThread(bid, "Foo", "bar")
+
+	std.TestSetOrigCaller(user)
+}
+
+func main() {
+	boards2.CreateReply(bid, tid, 0, "Test reply")
+}
+
+// Error:
+// unauthorized
diff --git a/examples/gno.land/r/nt/boards2/z_2_i_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_i_filetest.gno
new file mode 100644
index 00000000000..aa43805f7fd
--- /dev/null
+++ b/examples/gno.land/r/nt/boards2/z_2_i_filetest.gno
@@ -0,0 +1,27 @@
+package main
+
+import (
+	"std"
+
+	"gno.land/r/nt/boards2"
+)
+
+const owner = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+
+var (
+	bid boards2.BoardID
+	tid boards2.PostID
+)
+
+func init() {
+	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test-board")
+	tid = boards2.CreateThread(bid, "Foo", "bar")
+}
+
+func main() {
+	boards2.CreateReply(bid, tid, 0, "")
+}
+
+// Error:
+// body is empty
diff --git a/examples/gno.land/r/nt/boards2/z_2_j_filetest.gno b/examples/gno.land/r/nt/boards2/z_2_j_filetest.gno
new file mode 100644
index 00000000000..3449fb1c7ba
--- /dev/null
+++ b/examples/gno.land/r/nt/boards2/z_2_j_filetest.gno
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"std"
+	"strings"
+
+	"gno.land/r/nt/boards2"
+)
+
+const (
+	owner   = std.Address("g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5") // @test1
+	path    = "test-board/1/2"
+	comment = "Second comment"
+)
+
+var (
+	bid      boards2.BoardID
+	tid, rid boards2.PostID
+)
+
+func init() {
+	std.TestSetOrigCaller(owner)
+	bid = boards2.CreateBoard("test-board")
+	tid = boards2.CreateThread(bid, "Foo", "bar")
+	rid = boards2.CreateReply(bid, tid, 0, "First comment")
+}
+
+func main() {
+	rid2 := boards2.CreateReply(bid, tid, rid, comment)
+
+	// Ensure that returned ID is right
+	println(rid2 == 3)
+
+	// Render content must contain the sub-reply
+	content := boards2.Render(path)
+	println(strings.Contains(content, "\n> > "+comment+"\n"))
+}
+
+// Output:
+// true
+// true