diff --git a/admin_test.go b/admin_test.go
index 7c76376..3856873 100644
--- a/admin_test.go
+++ b/admin_test.go
@@ -92,6 +92,27 @@ func TestCreateIndexWithOptions(t *testing.T) {
 	})
 }
 
+// TestCreateIndexArithmeticTTL pins the BYT-9950 statement: arithmetic
+// expressions are not supported, and Execute must return a ParseError instead
+// of silently skipping the statement.
+func TestCreateIndexArithmeticTTL(t *testing.T) {
+	testutil.RunOnAllDBs(t, func(t *testing.T, db testutil.TestDB) {
+		dbName := fmt.Sprintf("testdb_create_idx_ttl_%s", db.Name)
+		defer testutil.CleanupDatabase(t, db.Client, dbName)
+
+		ctx := context.Background()
+
+		gc := gomongo.NewClient(db.Client)
+
+		_, err := gc.Execute(ctx, dbName, `db.cs_customer_frequency.createIndex(
+  { trans_date: 1 },
+  { expireAfterSeconds: 90 * 24 * 60 * 60, name: "cs_customer_frequency_idx2" }
+);`)
+		var pe *gomongo.ParseError
+		require.ErrorAs(t, err, &pe)
+	})
+}
+
 func TestDropIndex(t *testing.T) {
 	testutil.RunOnAllDBs(t, func(t *testing.T, db testutil.TestDB) {
 		dbName := fmt.Sprintf("testdb_drop_idx_%s", db.Name)
diff --git a/go.mod b/go.mod
index 693d6bf..c4935de 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module github.com/bytebase/gomongo
 go 1.25.7
 
 require (
-	github.com/bytebase/omni v0.0.0-20260509021101-01140a7b9722
+	github.com/bytebase/omni v0.0.0-20260730024920-8e82223f7635
 	github.com/google/uuid v1.6.0
 	github.com/stretchr/testify v1.11.1
 	github.com/testcontainers/testcontainers-go v0.41.0
diff --git a/go.sum b/go.sum
index 2188140..d1509d9 100644
--- a/go.sum
+++ b/go.sum
@@ -6,8 +6,8 @@ github.com/Azure/go-ansiterm v0.0.0-20250102033503-faa5f7b0171c h1:udKWzYgxTojEK
 github.com/Azure/go-ansiterm v0.0.0-20250102033503-faa5f7b0171c/go.mod h1:xomTg63KZ2rFqZQzSB4Vz2SUXa1BpHTVz9L5PTmPC4E=
 github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
-github.com/bytebase/omni v0.0.0-20260509021101-01140a7b9722 h1:zeMIExVxJVNoU3DZfrKrMMrdZTmUJ264bihZ3fDNcqo=
-github.com/bytebase/omni v0.0.0-20260509021101-01140a7b9722/go.mod h1:EVG8nQbNPUnUBGKn6J0niSGOs3jgfKo3TciY22R4bfo=
+github.com/bytebase/omni v0.0.0-20260730024920-8e82223f7635 h1:JBDU5vAImt6qBPy4bUDgWhuuc2NQzR6WTMtKRL51YjE=
+github.com/bytebase/omni v0.0.0-20260730024920-8e82223f7635/go.mod h1:Gp5RN3FM07f9/FFOTZCeu8duTAIMeuinkjjBCrs2Dw4=
 github.com/cenkalti/backoff/v4 v4.3.0 h1:MyRJ/UdXutAwSAT+s3wNd7MfTIcy71VQueUuFK343L8=
 github.com/cenkalti/backoff/v4 v4.3.0/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
 github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
diff --git a/internal/translator/translator.go b/internal/translator/translator.go
index e15a0b5..c66e296 100644
--- a/internal/translator/translator.go
+++ b/internal/translator/translator.go
@@ -5,10 +5,13 @@ import (
 
 	"github.com/bytebase/gomongo/types"
 	"github.com/bytebase/omni/mongo"
+	"github.com/bytebase/omni/mongo/ast"
 	"github.com/bytebase/omni/mongo/parser"
 )
 
-// Parse parses a MongoDB shell statement and returns the operation.
+// Parse parses a single MongoDB shell statement and returns the operation.
+// The input must contain exactly one executable statement: parse errors and
+// extra statements are rejected rather than silently dropped.
 //
 // Input that contains no executable statements (e.g., only comments or
 // whitespace) is treated as a no-op: Parse returns an Operation with
@@ -28,13 +31,23 @@ func Parse(statement string) (*Operation, error) {
 		return nil, err
 	}
 
-	// Find the first non-empty statement.
+	var node ast.Node
 	for _, s := range stmts {
-		if !s.Empty() {
-			return translateNode(s.AST)
+		if s.Empty() {
+			continue
 		}
+		if node != nil {
+			return nil, &ParseError{
+				Line:    s.Start.Line,
+				Column:  s.Start.Column,
+				Message: "expected a single statement, got multiple",
+			}
+		}
+		node = s.AST
 	}
-
-	// Comment-only / whitespace-only input: no-op, no error.
-	return &Operation{OpType: types.OpNoOp}, nil
+	if node == nil {
+		// Comment-only / whitespace-only input: no-op, no error.
+		return &Operation{OpType: types.OpNoOp}, nil
+	}
+	return translateNode(node)
 }
diff --git a/internal/translator/translator_test.go b/internal/translator/translator_test.go
new file mode 100644
index 0000000..2192494
--- /dev/null
+++ b/internal/translator/translator_test.go
@@ -0,0 +1,77 @@
+package translator
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/bytebase/gomongo/types"
+)
+
+// TestParseSingleStatementContract pins the strict single-statement contract:
+// parse errors and extra statements are rejected rather than silently dropped
+// (BYT-9950: dropped statements made migrations appear to skip commands).
+func TestParseSingleStatementContract(t *testing.T) {
+	t.Run("valid single statement", func(t *testing.T) {
+		op, err := Parse(`db.users.find({ name: "alice" })`)
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if op.OpType != types.OpFind {
+			t.Errorf("expected OpFind, got %v", op.OpType)
+		}
+	})
+
+	t.Run("comment-only input is a no-op", func(t *testing.T) {
+		op, err := Parse("// just a comment\n")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if op.OpType != types.OpNoOp {
+			t.Errorf("expected OpNoOp, got %v", op.OpType)
+		}
+	})
+
+	t.Run("invalid statement is rejected", func(t *testing.T) {
+		_, err := Parse("db.users.find({ name: })")
+		var pe *ParseError
+		if !errors.As(err, &pe) {
+			t.Fatalf("expected *ParseError, got %T: %v", err, err)
+		}
+	})
+
+	t.Run("valid statement followed by invalid is rejected", func(t *testing.T) {
+		_, err := Parse("db.users.find();\nthis is not mongosh")
+		var pe *ParseError
+		if !errors.As(err, &pe) {
+			t.Fatalf("expected *ParseError, got %T: %v", err, err)
+		}
+		if pe.Line != 2 {
+			t.Errorf("expected error on line 2, got %d", pe.Line)
+		}
+	})
+
+	t.Run("multiple valid statements are rejected", func(t *testing.T) {
+		_, err := Parse("db.users.find();\ndb.orders.find();")
+		var pe *ParseError
+		if !errors.As(err, &pe) {
+			t.Fatalf("expected *ParseError, got %T: %v", err, err)
+		}
+		if pe.Line != 2 {
+			t.Errorf("expected error on line 2, got %d", pe.Line)
+		}
+	})
+}
+
+// TestParseCreateIndexArithmeticTTL pins the BYT-9950 statement: arithmetic
+// expressions are not supported, and Parse must surface the error instead of
+// silently dropping the statement.
+func TestParseCreateIndexArithmeticTTL(t *testing.T) {
+	_, err := Parse(`db.cs_customer_frequency.createIndex(
+  { trans_date: 1 },
+  { expireAfterSeconds: 90 * 24 * 60 * 60, name: "cs_customer_frequency_idx2" }
+);`)
+	var pe *ParseError
+	if !errors.As(err, &pe) {
+		t.Fatalf("expected *ParseError, got %T: %v", err, err)
+	}
+}