diff --git a/internal/engine/generate/actions_test.go b/internal/engine/generate/actions_test.go
new file mode 100644
index 000000000..a518711a7
--- /dev/null
+++ b/internal/engine/generate/actions_test.go
@@ -0,0 +1,141 @@
+package generate
+
+import (
+	"testing"
+
+	"github.com/kwilteam/kwil-db/core/types"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGenerateActionBody(t *testing.T) {
+	tests := []struct {
+		name            string
+		action          *types.Action
+		schema          *types.Schema
+		pgSchema        string
+		wantErr         bool
+		wantGenActStmts []any
+	}{
+		{
+			name: "invalid schema",
+			action: &types.Action{
+				Name: "test_action",
+				Body: "SELECT * FROM nonexistent_table;",
+			},
+			schema:   nil,
+			pgSchema: "test_schema",
+			wantErr:  true,
+		},
+		{
+			name: "invalid SQL syntax",
+			action: &types.Action{
+				Name: "invalid_syntax",
+				Body: "SELECT * FROM;",
+			},
+			schema:   &types.Schema{},
+			pgSchema: "test_schema",
+			wantErr:  true,
+		},
+		{
+			name: "valid select action",
+			action: &types.Action{
+				Name: "valid_action",
+				Body: "SELECT id FROM users;",
+			},
+			schema: &types.Schema{
+				Tables: []*types.Table{
+					{
+						Name: "users",
+						Columns: []*types.Column{
+							{
+								Name: "id",
+								Type: types.IntType,
+								Attributes: []*types.Attribute{
+									{
+										Type: types.PRIMARY_KEY,
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			pgSchema: "test_schema",
+			wantErr:  false,
+		},
+		{
+			name: "faithful typecast with repeat variable number in (*sqlGenerator).VisitExpressionVariable",
+			action: &types.Action{
+				Name:       "insert_typecasts",
+				Parameters: []string{"$id", "$intval"},
+				Body: `INSERT INTO id_and_int (
+    id,
+    intval
+) VALUES (
+    uuid_generate_v5('31276fd4-105f-4ff7-9f64-644942c14b79'::uuid, format('%s-%s', $id::text, $intval::text)),
+    $intval::int
+);`,
+			},
+			schema: &types.Schema{
+				Tables: []*types.Table{
+					{
+						Name: "id_and_int",
+						Columns: []*types.Column{
+							{
+								Name: "id",
+								Type: types.UUIDType,
+								Attributes: []*types.Attribute{
+									{
+										Type: types.PRIMARY_KEY,
+									},
+								},
+							},
+							{
+								Name: "intval",
+								Type: types.IntType,
+							},
+						},
+					},
+				},
+			},
+			pgSchema: "test_schema",
+			wantErr:  false,
+			wantGenActStmts: []any{
+				&ActionSQL{
+					Statement: `
+INSERT INTO test_schema.id_and_int (id, intval) 
+VALUES 
+(uuid_generate_v5('31276fd4-105f-4ff7-9f64-644942c14b79'::UUID, format('%s-%s'::TEXT, $1::TEXT, $2::TEXT)), $2::INT8);`,
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			stmts, err := GenerateActionBody(tt.action, tt.schema, tt.pgSchema)
+			if tt.wantErr {
+				assert.Error(t, err)
+				return
+			}
+			assert.NoError(t, err)
+			assert.NotNil(t, stmts)
+
+			if len(tt.wantGenActStmts) == 0 {
+				return
+			}
+			for i, stmt := range stmts {
+				switch st := stmt.(type) {
+				case *ActionSQL:
+					wantStmt, ok := tt.wantGenActStmts[i].(*ActionSQL)
+					if !ok {
+						t.Errorf("wanted *ActionSQL, got %T", tt.wantGenActStmts[i])
+						return
+					}
+					assert.Equal(t, wantStmt.Statement, st.Statement)
+				default:
+				}
+			}
+		})
+	}
+}
diff --git a/internal/engine/generate/plpgsql.go b/internal/engine/generate/plpgsql.go
index d528d9fe9..972fabd69 100644
--- a/internal/engine/generate/plpgsql.go
+++ b/internal/engine/generate/plpgsql.go
@@ -127,7 +127,10 @@ func (s *sqlGenerator) VisitExpressionVariable(p0 *parse.ExpressionVariable) any
 		// if it already exists, we write it as that index.
 		for i, v := range s.orderedParams {
 			if v == str {
-				return "$" + strconv.Itoa(i+1)
+				res := strings.Builder{}
+				res.WriteString("$" + strconv.Itoa(i+1))
+				typeCast(p0, &res)
+				return res.String()
 			}
 		}