diff --git a/README.md b/README.md
index 58425e6..2f2dcc8 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,25 @@
 * This is a collection of pipelines built by 4DN-DCIC that were created and run either on the SevenBridges platform or on the 4DN platform, AWSEM.
 * The repo contains a benchmarking script for some of the CWLs, that returns total space, mem and CPUs required per given input size and a recommended AWS EC2 instance type.
 
+
+### Specification for 4DN
+* Currently, 4DN DCIC uses CWL `draft-3`.
+* The following 4DN custom fields are added, for automated conversion from cwl to the workflow metadata used by the 4DN Data Portal.
+  * `fdn_meta` (top level field) : a dictionary that contains `data_types`, `category`, `workflow_type`, `description`.
+    * `data_types` : an array of strings that correspond to the data types to be processed. e.g.) [ 'Repli-seq' ]
+    * `category` : a string describing the steps. e.g.) 'clip + align + filter + sort + dedup + count'
+    * `workflow_type` : a string describing the purpose of the workflow in short. e.g.) 'Repli-seq data processing'
+    * `description` : a string describing the workflow. e.g.) 'Repli-seq data processing pipeline'
+  * `fdn_step_meta` (within each `steps` element) : a dictionary that contains `software_used`, `description`, `analysis_step_types`.
+    * `software_used` : an array of strings that refer to the names of the software used. The name must match the names used in the `downloads.sh` in an accompanying Docker source repo. e.g.) [ 'cutadapt' ]
+    * `description` : a string that describes the step. e.g.) 'Adapter removal according to the Repli-seq pipeline'
+    * `analysis_step_types` : an array of strings that refer to the step types (i.e. purpose). e.g.) [ 'adapter removal' ]
+  * `fdn_format` (within each top-level `inputs` and `outputs` element) : a string. e.g.) 'bam'
+  * `fdn_output_type` (within each top-level `outputs` element) : a string that corresponds to one of the following three - 'processed', 'QC', 'report'
+    * processed : generic output file
+    * QC : output will be used to generate a quality_metric object (e.g. fastqc report)
+    * report : output will be used to add a metric to input (e.g. md5)
+
 ### How to run the cwl
 To run docker through CWL, you need a cwl executor - we use `cwltool` (https://github.com/common-workflow-language/cwltool) to run CWL with a json/yml file describing input data. Some example input data are inside the `tests/test_input_json` directory and you can see some `cwltool` (=`cwl-runner`) commands inside the `tests/tests.sh` script.
 
diff --git a/cwl_awsem/repliseq/repliseq-parta.cwl b/cwl_awsem/repliseq/repliseq-parta.cwl
index 2ce0db3..fbb8ab3 100644
--- a/cwl_awsem/repliseq/repliseq-parta.cwl
+++ b/cwl_awsem/repliseq/repliseq-parta.cwl
@@ -1,32 +1,46 @@
 {
+    "fdn_meta": {
+        "data_types": [ "Repli-seq" ],
+        "category": "align + filter + count",
+        "workflow_type": "Repli-seq data processing",
+        "description": "Repli-seq data processing pipeline"
+    },
     "outputs": [
         {
             "type": [
                 "File"
             ],
             "source": "#align.out_bam",
-            "id": "#bam"
+            "id": "#bam",
+            "fdn_format": "bam",
+            "fdn_output_type": "processed"
         },
         {
             "type": [
                 "File"
             ],
             "source": "#filtersort.out_filtered_sorted_bam",
-            "id": "#filtered_sorted_bam"
+            "id": "#filtered_sorted_bam",
+            "fdn_output_type": "processed",
+            "fdn_format": "bam"
         },
         {
             "type": [
                 "File"
             ],
             "source": "#dedup.out_deduped_bam",
-            "id": "#filtered_sorted_deduped_bam"
+            "id": "#filtered_sorted_deduped_bam",
+            "fdn_output_type": "processed",
+            "fdn_format": "bam"
         },
         {
             "type": [
                 "File"
             ],
             "source": "#count.out_count_bg",
-            "id": "#count_bg"
+            "id": "#count_bg",
+            "fdn_output_type": "processed",
+            "fdn_format": "bg"
         }
     ],
     "inputs": [
@@ -34,19 +48,22 @@
             "type": [
                 "File"
             ],
-            "id": "#fastq"
+            "id": "#fastq",
+            "fdn_format": "fastq"
         },
         {
             "type": [
                 "File"
             ],
-            "id": "#bwaIndex"
+            "id": "#bwaIndex",
+            "fdn_format": "bwaIndex"
         },
         {
             "type": [
                 "File"
             ],
-            "id": "#chromsizes"
+            "id": "#chromsizes",
+            "fdn_format": "chromsizes"
         },
         {
             "type": [
@@ -62,7 +79,7 @@
                 "string"
             ],
             "id": "#memperthread",
-            "default": "5G"
+            "default": "2G"
         },
         {
             "type": [
@@ -89,7 +106,12 @@
                     "id": "#clip.input_fastq"
                 }
             ],
-            "id": "#clip"
+            "id": "#clip",
+            "fdn_step_meta": {
+                "software_used": [ "cutadapt" ],
+                "description": "Adapter removal according to the Repli-seq pipeline",
+                "analysis_step_types": [ "adapter removal" ]
+            }
         },
         {
             "outputs": [
@@ -112,7 +134,12 @@
                     "id": "#align.nThreads"
                 }
             ],
-            "id": "#align"
+            "id": "#align",
+            "fdn_step_meta": {
+                "software_used": [ "bwa" ],
+                "description": "Alignment according to the Repli-seq pipeline",
+                "analysis_step_types": [ "alignment" ]
+            }
         },
         {
             "outputs": [
@@ -135,7 +162,12 @@
                     "id": "#filtersort.memperthread"
                 }
             ],
-            "id": "#filtersort"
+            "id": "#filtersort",
+            "fdn_step_meta": {
+                "software_used": [ "samtools" ],
+                "description": "Filtering and sorting according to the Repli-seq pipeline",
+                "analysis_step_types": [ "filtering", "sorting" ]
+            }
         },
         {
             "outputs": [
@@ -150,7 +182,12 @@
                     "id": "#dedup.input_bam"
                 }
             ],
-            "id": "#dedup"
+            "id": "#dedup",
+            "fdn_step_meta": {
+                "software_used": [ "samtools" ],
+                "description": "PCR Duplicate removal according to the Repli-seq pipeline",
+                "analysis_step_types": [ "duplicate removal" ]
+            }
         },
         {
             "outputs": [
@@ -173,7 +210,12 @@
                     "id": "#count.winsize"
                 }
             ],
-            "id": "#count"
+            "id": "#count",
+            "fdn_step_meta": {
+                "software_used": [ "bedtools" ],
+                "description": "Read aggregation according to the Repli-seq pipeline",
+                "analysis_step_types": [ "binning", "aggregation" ]
+            }
         }
     ],
     "requirements": [