diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
index 58d4616d9..e6f1487b8 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
@@ -193,6 +193,7 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
   private boolean allowLoadingDuplicates;
 
   protected TerminologyClient txClient;
+  private Set<String> codeSystemsUsed = new HashSet<>();
   protected ToolingClientLogger txLog;
   private TerminologyCapabilities txcaps;
   private boolean canRunWithoutTerminology;
@@ -602,7 +603,12 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
     if (cached) {
       p.addParameter().setName("cache-id").setValue(new StringType(cacheId));              
     }
-    ;
+    for (ConceptSetComponent incl : vs.getCompose().getInclude()) {
+      codeSystemsUsed.add(incl.getSystem());
+    }
+    for (ConceptSetComponent incl : vs.getCompose().getExclude()) {
+      codeSystemsUsed.add(incl.getSystem());
+    }
     
     if (noTerminologyServer) {
       return new ValueSetExpansionOutcome(formatMessage(I18nConstants.ERROR_EXPANDING_VALUESET_RUNNING_WITHOUT_TERMINOLOGY_SERVICES), TerminologyServiceErrorClass.NOSERVICE);
@@ -642,6 +648,12 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
     if (!vs.hasUrl()) {
       throw new Error(formatMessage(I18nConstants.NO_VALUE_SET_IN_URL));
     }
+    for (ConceptSetComponent inc : vs.getCompose().getInclude()) {
+      codeSystemsUsed.add(inc.getSystem());
+    }
+    for (ConceptSetComponent inc : vs.getCompose().getExclude()) {
+      codeSystemsUsed.add(inc.getSystem());
+    }
 
     CacheToken cacheToken = txCache.generateExpandToken(vs, heirarchical);
     ValueSetExpansionOutcome res;
@@ -738,6 +750,7 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
     // 3rd pass: hit the server
     for (CodingValidationRequest t : codes) {
       t.setCacheToken(txCache != null ? txCache.generateValidationToken(options, t.getCoding(), vs) : null);
+      codeSystemsUsed.add(t.getCoding().getSystem());
       if (txCache != null) { 
         t.setResult(txCache.getValidation(t.getCacheToken()));
       }
@@ -833,6 +846,7 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
       options = ValidationOptions.defaults();
     }
     
+    codeSystemsUsed.add(code.getSystem());
     CacheToken cacheToken = txCache != null ? txCache.generateValidationToken(options, code, vs) : null;
     ValidationResult res = null;
     if (txCache != null) {
@@ -907,6 +921,9 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
     if (res != null) {
       return res;
     }
+    for (Coding c : code.getCoding()) {
+      codeSystemsUsed.add(c.getSystem());
+    }
 
     if (options.isUseClient()) {
       // ok, first we try to validate locally
@@ -945,6 +962,14 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
 
   private ValidationResult validateOnServer(ValueSet vs, Parameters pin) throws FHIRException {
     boolean cache = false;
+    if (vs != null) {
+      for (ConceptSetComponent inc : vs.getCompose().getInclude()) {
+        codeSystemsUsed.add(inc.getSystem());
+      }
+      for (ConceptSetComponent inc : vs.getCompose().getExclude()) {
+        codeSystemsUsed.add(inc.getSystem());
+      }
+    }
     if (vs != null) {
       if (isTxCaching && cacheId != null && cached.contains(vs.getUrl()+"|"+vs.getVersion())) {
         pin.addParameter().setName("url").setValue(new UriType(vs.getUrl()+"|"+vs.getVersion()));        
@@ -1945,5 +1970,22 @@ public abstract class BaseWorkerContext extends I18nBase implements IWorkerConte
         guides.size() + capstmts.size() + searchParameters.size() + questionnaires.size() + operations.size() + plans.size() + systems.size();
   }
 
+  public Set<String> getCodeSystemsUsed() {
+    return codeSystemsUsed ;
+  }
+ 
+  public String getSpecUrl() {
+    String v = getVersion();
+    switch (VersionUtilities.getMajMin(v)) {
+    case "1.0" : return "http://hl7.org/fhir/DSTU1";
+    case "1.4" : return "http://hl7.org/fhir/DSTU2";
+    case "3.0" : return "http://hl7.org/fhir/STU3";
+    case "4.0" : return "http://hl7.org/fhir/R4";
+    case "4.5" : return "http://build.fhir.org";
+    case "5.0" : return "http://build.fhir.org";
+    default:
+      return "http://hl7.org/fhir";
+    }
+  }
 
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java
index 72b79b4bd..01dd321cb 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java
@@ -222,7 +222,12 @@ public interface IWorkerContext {
    * Get the versions of the definitions loaded in context
    * @return
    */
-  public String getVersion();
+  public String getVersion();
+  
+  /**
+   * return the link to the base of the specification for the loaded version e.g. http://hl7.org/fhir/R4
+   */
+  public String getSpecUrl();
   
   // get the UCUM service (might not be available)
   public UcumService getUcumService();
@@ -710,7 +715,7 @@ public interface IWorkerContext {
   public ILoggingService getLogger();
 
   public boolean isNoTerminologyServer();
-
+  public Set<String> getCodeSystemsUsed();
   public TranslationServices translator();
   public List<StructureMap> listTransforms();
   public StructureMap getTransform(String url);