diff --git a/Makefile b/Makefile
index b2cf58591aa..92b565985d3 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@ API_DEPS = .api.deps
 API_SHARED_INFO = etc/api/shared.yaml
 API_JSON_FILES = $(shell find etc -type f -name '*-api.json')
 MAKO_LIB_DIR = $(MAKO_SRC)/lib
-MAKO_LIB_FILES = $(shell find $(MAKO_LIB_DIR) -type f -name '*.mako' -or -name '*.py')
+MAKO_LIB_FILES = $(shell find $(MAKO_LIB_DIR) -type f -name '*.*')
 
 help:
 	$(info using template engine: '$(TPL)')
diff --git a/src/mako/lib.rs.mako b/src/mako/lib.rs.mako
index 3f64c4c2019..5551aa4b8c7 100644
--- a/src/mako/lib.rs.mako
+++ b/src/mako/lib.rs.mako
@@ -19,6 +19,8 @@ extern crate "yup-oauth2" as oauth2;
 
 use std::collections::HashMap;
 
+use cmn::{Resource, Part, ResponseResult, RequestResult, NestedType};
+
 // ############
 // SCHEMAS ###
 // ##########
diff --git a/src/mako/lib/schema.mako b/src/mako/lib/schema.mako
index 4b9311da494..9c0ae36607b 100644
--- a/src/mako/lib/schema.mako
+++ b/src/mako/lib/schema.mako
@@ -2,7 +2,10 @@
 ## Create new schema with everything.
 ## 's' contains the schema structure from json to build
 <%def name="new(s, c)">\
-<% assert s.type == "object" %>\
+<% 
+	assert s.type == "object" 
+	markers = util.schema_markers(s, c)
+%>\
 <%block filter="util.rust_doc_comment">\
 ${doc(s, c)}\
 </%block>
@@ -18,6 +21,10 @@ pub struct ${s.id}\
 % else:
 ;
 % endif
+
+% for marker_trait in markers:
+impl ${marker_trait} for ${s.id} {}
+% endfor
 </%def>
 
 <%def name="doc(s, c)">\
@@ -26,7 +33,11 @@ ${s.get('description', 'There is no detailed description.')}
 
 # Activities
 
-${''.join("* %s\n" % a for a in c.sta_map[s.id].keys())}
+This type is used in activities, which are methods you may call on this type or where this type is involved in. 
+The list links the activity name, along with information about where it is used (one of ${util.put_and(util.IO_TYPES)}.
+
+${''.join("* %s (%s)\n" % (util.activity_split(a)[1], iot and '|'.join(iot) or 'none') 
+													for a, iot in c.sta_map[s.id].iteritems())}
 % else:
 
 This schema type is not used in any activity, and only used as *part* of another schema.
diff --git a/src/mako/lib/util.py b/src/mako/lib/util.py
index 74ca01cb36c..fd01bd0b4f3 100644
--- a/src/mako/lib/util.py
+++ b/src/mako/lib/util.py
@@ -14,9 +14,14 @@
             'string'  : 'String',
             'object'  : 'HashMap'}
 TREF = '$ref'
+IO_RESPONSE = 'response'
+IO_REQUEST = 'request'
+IO_TYPES = (IO_REQUEST, IO_RESPONSE)
 INS_METHOD = 'insert'
 DEL_METHOD = 'delete'
 
+NESTED_TYPE_MARKER = 'is_nested'
+
 # ==============================================================================
 ## @name Filters
 # ------------------------------------------------------------------------------
@@ -79,7 +84,7 @@ def nested_type(nt):
         elif nt.get('additionalProperties'):
             nt = nt.additionalProperties
         else:
-            assert(is_nested_type(nt))
+            assert(is_nested_type_property(nt))
             # It's a nested type - we take it literally like $ref, but generate a name for the type ourselves
             # This of course assumes
             return nested_type_name(sn, pn)
@@ -112,8 +117,13 @@ def nested_type(nt):
     except AttributeError as err:
         raise AssertionError("%s: unknown dict layout: %s" % (str(err), t))
 
-def is_nested_type(t):
-    return 'type' in t and t.type == 'object' and 'additionalProperties' not in t
+# return True if this property is actually a nested type
+def is_nested_type_property(t):
+    return 'type' in t and t.type == 'object' and 'properties' in t
+
+# Return True if the schema is nested
+def is_nested_type(s):
+    return NESTED_TYPE_MARKER in s
 
 # return an iterator yielding fake-schemas that identify a nested type
 def iter_nested_types(schemas):
@@ -121,13 +131,38 @@ def iter_nested_types(schemas):
         if 'properties' not in s:
             continue
         for pn, p in s.properties.iteritems():
-            if is_nested_type(p):
+            if is_nested_type_property(p):
                 ns = p.copy()
                 ns.id = nested_type_name(s.id, pn)
+                ns[NESTED_TYPE_MARKER] = True
                 yield ns
         # end for ach property
     # end for aech schma
 
+# Return sorted type names of all markers applicable to the given schema
+def schema_markers(s, c):
+    res = set()
+
+    activities = c.sta_map.get(s.id, dict())
+    if len(activities) == 0:
+        res.add('Part')
+    else:
+        # it should have at least one activity that matches it's type to qualify for the Resource trait
+        for fqan, iot in activities.iteritems():
+            if activity_name_to_type_name(activity_split(fqan)[0]) == s.id:
+                res.add('Resource')
+            if IO_RESPONSE in iot:
+                res.add('ResponseResult')
+            if IO_REQUEST in iot:
+                res.add('RequestResult')
+        # end for each activity
+    # end handle activites
+
+    if is_nested_type(s):
+        res.add('NestedType')
+
+    return sorted(res)
+
 ## -- End Rust TypeSystem -- @}
 
 
@@ -148,7 +183,7 @@ def build_activity_mappings(activities):
         for mn, m in a.methods.iteritems():
             assert m.id not in fqan
             fqan[m.id] = m
-            for in_out_type_name in ('request', 'response'):
+            for in_out_type_name in IO_TYPES:
                 t = m.get(in_out_type_name, None)
                 if t is None:
                     continue
@@ -163,12 +198,10 @@ def build_activity_mappings(activities):
             # getrating: response is a 'SomethingResult', which is still related to activities name
             #            the latter is used to deduce the resource name
             an, _ = activity_split(m.id)
-            # videos -> Video
-            an = an.capitalize()[:-1]
-            info = res.setdefault(an, dict())
+            tn = activity_name_to_type_name(an)
+            info = res.setdefault(tn, dict())
             if m.id not in info:
-                io_info = info.setdefault(m.id, [])
-                io_info.append([])
+                info.setdefault(m.id, [])
             # end handle other cases
         # end for each method
     # end for each activity
@@ -180,6 +213,10 @@ def activity_split(fqan):
     assert len(t) == 3
     return t[1:]
 
+# videos -> Video
+def activity_name_to_type_name(an):
+    return an.capitalize()[:-1]
+
 ## -- End Activity Utilities -- @}
 
 
diff --git a/src/rust/lib.rs b/src/rust/lib.rs
index f353eded45d..01f850fb6cf 100644
--- a/src/rust/lib.rs
+++ b/src/rust/lib.rs
@@ -3,6 +3,26 @@ extern crate hyper;
 extern crate "rustc-serialize" as rustc_serialize;
 extern crate "yup-oauth2" as oauth2;
 
+use std::marker::MarkerTrait;
+
+/// Identifies types which can be inserted and deleted.
+/// Types with this trait are most commonly used by clients of this API.
+pub trait Resource: MarkerTrait {}
+
+/// Identifies types which are used in API responses.
+pub trait ResponseResult: MarkerTrait {}
+
+/// Identifies types which are used in API requests.
+pub trait RequestResult: MarkerTrait {}
+
+/// Identifies types which are only used as part of other types, which 
+/// usually are carrying the `Resource` trait.
+pub trait Part: MarkerTrait {}
+
+/// Identifies types which are only used by other types internally.
+/// They have no special meaning, this trait just marks them for completeness.
+pub trait NestedType: MarkerTrait {}
+
 /// This module is for testing only, its code is used in mako templates
 #[cfg(test)]
 mod dev;
\ No newline at end of file