diff --git a/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoFrameWriter.java b/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoFrameWriter.java
index 59303273f4..f07fe1eac0 100644
--- a/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoFrameWriter.java
+++ b/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoFrameWriter.java
@@ -8,6 +8,7 @@
 import org.jlab.jnp.hipo4.data.Event;
 import org.jlab.jnp.hipo4.io.HipoWriterStream;
 import org.jlab.jnp.utils.file.FileUtils;
+import org.jlab.utils.ClaraYaml;
 import org.json.JSONObject;
 
 /**
@@ -47,9 +48,14 @@ private int getCompression(JSONObject opts) {
     }
 
     private String getSchemaDirectory(JSONObject opts) {
-        return opts.has(CONF_SCHEMA)
-                ? opts.getString(CONF_SCHEMA)
-                : FileUtils.getEnvironmentPath("CLAS12DIR", "etc/bankdefs/hipo4");
+        String s = FileUtils.getEnvironmentPath("CLAS12DIR", "etc/bankdefs/hipo4");
+        if (opts.has(CONF_SCHEMA)) {
+            s = opts.getString(CONF_SCHEMA).trim();
+            // If it's not already an absolute path, assume it's the name of a
+            // stock schema that comes with COATJAVA and get the full path to it:
+            if (!s.startsWith("/")) s = ClaraYaml.getStockSchemaDirectory(opts.getString(s));
+        }
+        return s;
     }
 
     private String[] getFilterString(JSONObject opts){
diff --git a/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoToHipoWriter.java b/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoToHipoWriter.java
index caf29c4616..df83b1c069 100644
--- a/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoToHipoWriter.java
+++ b/common-tools/clara-io/src/main/java/org/jlab/io/clara/HipoToHipoWriter.java
@@ -15,6 +15,7 @@
 import org.jlab.jnp.hipo4.io.HipoWriter;
 import org.jlab.jnp.hipo4.io.HipoWriterSorted;
 import org.jlab.jnp.utils.file.FileUtils;
+import org.jlab.utils.ClaraYaml;
 import org.json.JSONObject;
 
 /**
@@ -46,7 +47,6 @@ protected HipoWriterSorted createWriter(Path file, JSONObject opts) throws Event
             throw new EventWriterException(e);
         }
     }
-
     
     protected void configure(HipoWriterSorted writer, JSONObject opts) {
         schemaBankList.clear();
@@ -58,8 +58,12 @@ protected void configure(HipoWriterSorted writer, JSONObject opts) {
 
         String schemaDir = FileUtils.getEnvironmentPath("CLAS12DIR", "etc/bankdefs/hipo4");
         if (opts.has(CONF_SCHEMA_DIR)) {
-            schemaDir = opts.getString(CONF_SCHEMA_DIR);
+            // Run YAML values throuh env-substitor: 
+            schemaDir = opts.getString(CONF_SCHEMA_DIR).trim();
             schemaDir = envSubstitutor.replace(schemaDir);
+            // If it's not already an absolute path, assume it's the name of a
+            // stock schema that comes with COATJAVA and get the full path to it:
+            if (!schemaDir.startsWith("/")) schemaDir = ClaraYaml.getStockSchemaDirectory(schemaDir);
             System.out.printf("%s service: schema directory = %s%n", getName(), schemaDir);
         }
 
diff --git a/common-tools/clas-io/src/main/java/org/jlab/utils/ClaraYaml.java b/common-tools/clas-io/src/main/java/org/jlab/utils/ClaraYaml.java
index 957894fd3c..b6525bfb3b 100644
--- a/common-tools/clas-io/src/main/java/org/jlab/utils/ClaraYaml.java
+++ b/common-tools/clas-io/src/main/java/org/jlab/utils/ClaraYaml.java
@@ -8,6 +8,7 @@
 import java.util.Map;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import org.jlab.utils.system.ClasUtilsFile;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.yaml.snakeyaml.Yaml;
@@ -21,19 +22,19 @@
  */
 public class ClaraYaml {
 
-    private Yaml yaml = null;
     private JSONObject json = null;
 
     public ClaraYaml(String filename) {
         InputStream input;
         try {
             input = new FileInputStream(filename);
-            this.yaml = new Yaml();
+            Yaml yaml = new Yaml();
             Map<String, Object> yamlConf = (Map<String, Object>) yaml.load(input);
             this.json = new JSONObject(yamlConf);
         } catch (FileNotFoundException ex) {
             Logger.getLogger(ClaraYaml.class.getName()).log(Level.SEVERE, null, ex);
         }
+        setStockSchemaDirectory();
     }
 
     /**
@@ -93,6 +94,44 @@ public String schemaDirectory() {
         return null;
     }
 
+    public String getSchemaDirectory() {
+        return schemaDirectory();
+    }
+
+    /**
+     * Set the schema_dir directory.
+     * @param dir path to schema_dir directory
+     */ 
+    public void setSchemaDirectory(String dir) {
+        if (!json.has("configuration"))
+            json.put("configuration",new JSONObject());
+        if (!json.getJSONObject("configuration").has("io_services")) 
+            json.getJSONObject("configuration").put("io-services",new JSONObject());
+        if (!json.getJSONObject("configuration").getJSONObject("io-services").has("writer"))
+            json.getJSONObject("configuration").getJSONObject("io-services").put("writer",new JSONObject());
+        this.json.getJSONObject("configuration").getJSONObject("io-services").
+            getJSONObject("writer").put("schema_dir",dir);
+    }
+   
+    /**
+     * Set the schema_dir, assuming it's currently the short (basename) of a
+     * "stock" schema, but only if it doesn't already look like an absolute path.
+     */
+    public final void setStockSchemaDirectory() {
+        String s = getSchemaDirectory();
+        if (s != null && !s.trim().startsWith("/")) 
+            setSchemaDirectory(getStockSchemaDirectory(s));
+    }
+
+    /**
+     * Convert short (base)name into absolute path, for "stock" schema.
+     * @param name
+     * @return 
+     */
+    public static String getStockSchemaDirectory(String name) {
+        return ClasUtilsFile.getResourceDir("CLAS12DIR", "etc/bankdefs/hipo4/singles/"+name);
+    }
+
     /**
      * Get the service's configuration as presented by CLARA.
      * @param serviceName
@@ -135,10 +174,12 @@ public static JSONObject filter(JSONObject claraJson, String serviceName) {
     }
 
     public static void main(String[] args) {
-        ClaraYaml yaml = new ClaraYaml("/Users/baltzell/data-ai.yaml");
+        ClaraYaml yaml = new ClaraYaml(System.getenv("HOME")+"/sw/coatjava/github/etc/services/data-ai.yaml");
         yaml.show();
-        yaml.showFiltered("DCCR");
         yaml.showFiltered("EBTB");
+        yaml.setSchemaDirectory("dst");
+        yaml.setStockSchemaDirectory();
+        yaml.show();
     }
 
 }