diff --git a/libopenfpga/libarchopenfpga/src/circuit_library.cpp b/libopenfpga/libarchopenfpga/src/circuit_library.cpp
index a94b4b8a2..f9c101aff 100644
--- a/libopenfpga/libarchopenfpga/src/circuit_library.cpp
+++ b/libopenfpga/libarchopenfpga/src/circuit_library.cpp
@@ -235,6 +235,24 @@ CircuitModelId CircuitLibrary::pass_gate_logic_model(const CircuitModelId& model
   return pgl_model_id;
 }
 
+/* Find the name of pass-gate circuit model 
+ * Two cases to be considered:
+ * 1. this is a pass-gate circuit model, just find the data and return
+ * 2. this circuit model includes a pass-gate, find the link to pass-gate circuit model and go recursively
+ */
+std::string CircuitLibrary::pass_gate_logic_model_name(const CircuitModelId& model_id) const {
+  /* validate the model_id */
+  VTR_ASSERT(valid_model_id(model_id));
+  
+  /* Return the data if this is a pass-gate circuit model */
+  if (CIRCUIT_MODEL_PASSGATE == model_type(model_id)) {
+    return model_names_[model_id];
+  }
+
+  /* Otherwise, we need to make sure this circuit model contains a pass-gate */
+  return pass_gate_logic_model_names_[model_id];
+}
+
 /* Return the type of pass gate logic module, only applicable to circuit model whose type is pass-gate logic */
 enum e_circuit_model_pass_gate_logic_type CircuitLibrary::pass_gate_logic_type(const CircuitModelId& model_id) const {
   /* validate the model_id */
diff --git a/libopenfpga/libarchopenfpga/src/circuit_library.h b/libopenfpga/libarchopenfpga/src/circuit_library.h
index 4150ceebf..130b08c4e 100644
--- a/libopenfpga/libarchopenfpga/src/circuit_library.h
+++ b/libopenfpga/libarchopenfpga/src/circuit_library.h
@@ -27,6 +27,15 @@
  * The class CircuitLibrary is a critical data structure for OpenFPGA
  * It stores all the circuit-level details from XML architecture file
  *
+ * Typical usage:
+ *   // Create an empty circuit library
+ *   CircuitLibrary circuit_lib;
+ *   // call your builder for circuit library
+ *   // Build the internal links for the circuit library
+ *   circuit_lib.build_model_links();
+ *   // Build the timing graph inside the circuit library
+ *   circuit_lib.build_timing_graphs();
+ *
  * It includes the following data:
  *
  *  ------ Fundamental Information -----
@@ -197,6 +206,7 @@ class CircuitLibrary {
     std::string lut_intermediate_buffer_location_map(const CircuitModelId& model_id) const;
     /* Pass-gate-logic information */
     CircuitModelId pass_gate_logic_model(const CircuitModelId& model_id) const;
+    std::string pass_gate_logic_model_name(const CircuitModelId& model_id) const;
     enum e_circuit_model_pass_gate_logic_type pass_gate_logic_type(const CircuitModelId& model_id) const;
     float pass_gate_logic_pmos_size(const CircuitModelId& model_id) const;
     float pass_gate_logic_nmos_size(const CircuitModelId& model_id) const;
diff --git a/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp b/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp
index 20f701028..236dac68c 100644
--- a/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp
+++ b/libopenfpga/libarchopenfpga/src/read_xml_openfpga_arch.cpp
@@ -41,6 +41,12 @@ OpenFPGAArch read_xml_openfpga_arch(const char* arch_file_name) {
     auto xml_circuit_models = get_single_child(xml_circuit_settings, "circuit_library", loc_data);
     openfpga_arch.circuit_lib = read_xml_circuit_library(xml_circuit_models, loc_data);
 
+    /* Build the internal links for the circuit library */
+    openfpga_arch.circuit_lib.build_model_links();
+  
+    /* Build the timing graph inside the circuit library */
+    openfpga_arch.circuit_lib.build_timing_graphs();
+
   } catch (pugiutil::XmlError& e) {
     archfpga_throw(arch_file_name, e.line(),
                    "%s", e.what());
diff --git a/libopenfpga/libarchopenfpga/src/write_xml_circuit_library.cpp b/libopenfpga/libarchopenfpga/src/write_xml_circuit_library.cpp
index 60acf66d9..a162838a4 100644
--- a/libopenfpga/libarchopenfpga/src/write_xml_circuit_library.cpp
+++ b/libopenfpga/libarchopenfpga/src/write_xml_circuit_library.cpp
@@ -241,13 +241,64 @@ void write_xml_circuit_model(std::fstream& fp,
   /* Write the design technology of circuit model */
   write_xml_design_technology(fp, fname, circuit_lib, model);
 
-  /* TODO: Write the input buffer information of circuit model */
-  /* TODO: Write the output buffer information of circuit model */
-  /* TODO: Write the lut input buffer information of circuit model */
-  /* TODO: Write the lut input inverter information of circuit model */
-  /* TODO: Write the lut intermediate buffer information of circuit model */
+  /* Write the input buffer information of circuit model, 
+   * only applicable when this circuit model is neither inverter nor buffer
+   */
+  if (CIRCUIT_MODEL_INVBUF != circuit_lib.model_type(model)) {
+    if (true == circuit_lib.is_input_buffered(model)) {
+      fp << "\t\t\t" << "<input_buffer";
+      write_xml_attribute(fp, "exist", circuit_lib.is_input_buffered(model)); 
+      write_xml_attribute(fp, "circuit_model_name", circuit_lib.model_name(circuit_lib.input_buffer_model(model)).c_str()); 
+      fp << "/>" << "\n";
+    }
+  }
 
-  /* TODO: Write the pass-gate-logic information of circuit model */
+  /* Write the output buffer information of circuit model */
+  if (CIRCUIT_MODEL_INVBUF != circuit_lib.model_type(model)) {
+    if (true == circuit_lib.is_output_buffered(model)) {
+      fp << "\t\t\t" << "<output_buffer";
+      write_xml_attribute(fp, "exist", circuit_lib.is_input_buffered(model)); 
+      write_xml_attribute(fp, "circuit_model_name", circuit_lib.model_name(circuit_lib.output_buffer_model(model)).c_str()); 
+      fp << "/>" << "\n";
+    }
+  }
+
+  if (CIRCUIT_MODEL_LUT == circuit_lib.model_type(model)) {
+    /* Write the lut input buffer information of circuit model
+     * This is a mandatory attribute for LUT, so it must exist 
+     */
+    fp << "\t\t\t" << "<lut_input_buffer";
+    write_xml_attribute(fp, "exist", true); 
+    write_xml_attribute(fp, "circuit_model_name", circuit_lib.model_name(circuit_lib.lut_input_buffer_model(model)).c_str()); 
+    fp << "/>" << "\n";
+
+    /* Write the lut input inverter information of circuit model
+     * This is a mandatory attribute for LUT, so it must exist 
+     */
+    fp << "\t\t\t" << "<lut_input_inverter";
+    write_xml_attribute(fp, "exist", true); 
+    write_xml_attribute(fp, "circuit_model_name", circuit_lib.model_name(circuit_lib.lut_input_inverter_model(model)).c_str()); 
+    fp << "/>" << "\n";
+
+    /* Write the lut intermediate buffer information of circuit model */
+    if (true == circuit_lib.is_lut_intermediate_buffered(model)) {
+      fp << "\t\t\t" << "<lut_intermediate_buffer";
+      write_xml_attribute(fp, "exist", circuit_lib.is_lut_intermediate_buffered(model)); 
+      write_xml_attribute(fp, "circuit_model_name", circuit_lib.model_name(circuit_lib.lut_intermediate_buffer_model(model)).c_str()); 
+      if (!circuit_lib.lut_intermediate_buffer_location_map(model).empty()) {
+        write_xml_attribute(fp, "location_map", circuit_lib.lut_intermediate_buffer_location_map(model).c_str());
+      }
+      fp << "/>" << "\n";
+    }
+  }
+
+  /* Write the pass-gate-logic information of circuit model */
+  if ( (CIRCUIT_MODEL_LUT == circuit_lib.model_type(model)) 
+    || (CIRCUIT_MODEL_MUX == circuit_lib.model_type(model)) ) {
+    fp << "\t\t\t" << "<pass_gate_logic";
+    write_xml_attribute(fp, "circuit_model_name", circuit_lib.model_name(circuit_lib.pass_gate_logic_model(model)).c_str()); 
+    fp << "/>" << "\n";
+  }
 
   /* Write the ports of circuit model */
   for (const CircuitPortId& port : circuit_lib.model_ports(model)) {
@@ -264,6 +315,11 @@ void write_xml_circuit_model(std::fstream& fp,
 
 /********************************************************************
  * A writer to output a circuit library to XML format
+ * Note: 
+ * This function should be run after that the following methods of 
+ * CircuitLibrary are executed 
+ * 1. build_model_links();
+ * 2. build_timing_graph();
  *******************************************************************/
 void write_xml_circuit_library(std::fstream& fp,
                                const char* fname,
diff --git a/libopenfpga/libarchopenfpga/src/write_xml_utils.cpp b/libopenfpga/libarchopenfpga/src/write_xml_utils.cpp
index b7b02b272..0c782f328 100644
--- a/libopenfpga/libarchopenfpga/src/write_xml_utils.cpp
+++ b/libopenfpga/libarchopenfpga/src/write_xml_utils.cpp
@@ -5,6 +5,9 @@
 #include <fstream> 
 #include <string> 
 
+/* Headers from vtrutil library */
+#include "vtr_assert.h" 
+
 /* Headers from openfpgautil library */
 #include "openfpga_digest.h" 
 
@@ -22,3 +25,23 @@ void write_xml_attribute(std::fstream& fp,
 
   fp << " " << attr << "=\"" << value << "\""; 
 }
+
+/********************************************************************
+ * A most utilized function to write an XML attribute to file
+ * This accepts the value as a boolean 
+ *******************************************************************/
+void write_xml_attribute(std::fstream& fp, 
+                         const char* attr,
+                         const bool& value) {
+  /* Validate the file stream */
+  openfpga::valid_file_stream(fp);
+
+  fp << " " << attr << "=\"";
+  if (true == value) {
+    fp << "true"; 
+  } else {
+    VTR_ASSERT_SAFE(false == value);
+    fp << "false"; 
+  }
+  fp << "\""; 
+}
diff --git a/libopenfpga/libarchopenfpga/src/write_xml_utils.h b/libopenfpga/libarchopenfpga/src/write_xml_utils.h
index cafea189d..adb90262a 100644
--- a/libopenfpga/libarchopenfpga/src/write_xml_utils.h
+++ b/libopenfpga/libarchopenfpga/src/write_xml_utils.h
@@ -14,4 +14,8 @@ void write_xml_attribute(std::fstream& fp,
                          const char* attr,
                          const char* value);
 
+void write_xml_attribute(std::fstream& fp, 
+                         const char* attr,
+                         const bool& value);
+
 #endif
diff --git a/libopenfpga/libarchopenfpga/test/main.cpp b/libopenfpga/libarchopenfpga/test/main.cpp
index 624d9669f..4280f84e4 100644
--- a/libopenfpga/libarchopenfpga/test/main.cpp
+++ b/libopenfpga/libarchopenfpga/test/main.cpp
@@ -20,7 +20,7 @@ int main(int argc, const char** argv) {
   VTR_LOG("Parsed %lu circuit models from XML into circuit library.\n",
           openfpga_arch.circuit_lib.num_models());
 
-  /* Check the circuit library */
+  /* TODO: Check the circuit library */
   
   /* Output the circuit library to an XML file
    * This is optional only used when there is a second argument