diff --git a/claim.capnp b/claim.capnp
index f2c10d4..a642993 100644
--- a/claim.capnp
+++ b/claim.capnp
@@ -6,21 +6,25 @@ $CSharp.namespace("FabAccessAPI.Schema");
 using import "/capnp/rpc.capnp".SturdyRef;
 
 using import "persistent.capnp".Persistent;
-using import "state.capnp".State;
-using import "state.capnp".Update;
+using import "resource.capnp".Resource;
+using import "notify.capnp".Notifiable;
+using import "utils.capnp".Fallible;
+using import "utils.capnp".OID;
+using import "utils.capnp".Map;
 
 interface Claimable {
-    restore @0 ( sturdy :SturdyRef ) -> ( claim :Claim );
-    # Restore a previously saved SturdyRef pointing to a Claim
-
-    claim @1 () -> ( claim :Claim );
+    claim @0 () -> Fallible(Claim, ClaimError);
     # returns NULL if the resource is *currently* not claimable.
     # drop the returned claim capability to unclaim it.
+
+    interface ClaimError {
+
+    }
 }
 
 interface Lockable {
     restore @0 ( sturdy :SturdyRef ) -> ( lock :Lock );
-    # Restore a previously saved SturdyRef pointing to a Claim
+    # Restore a previously saved SturdyRef pointing to a Lock
 
     lock @1 () -> ( lock :Lock );
     # Take exclusive access to a resource, disowning all other claims on this resource.
@@ -33,22 +37,15 @@ interface Lockable {
     # lock.
 }
 
-interface Claim extends (Persistent) {
-    update @0 ( update :Update ) -> ( error :Error );
-    # Atomically update a resource via a claim.
-    #
-    # The parameter `update` is a list of `UpdateValue` that specify a list of behaviours to be
-    # updated with the associated data.  The format of this data depends on and is defined by the
-    # behaviour.
-    # An update call is atomic, if any one of the UpdateValue can not be applied
-    # the entire update call fails and is not applied.  A client may send multiple update calls in
-    # parallel to opt out of the atomic behaviour of update. The ordering in which multiple
-    # update calls are applied is not specified, a client MUST NOT rely on updates happening in the
-    # order they are sent.
-    # The returned `error` is NULL if the update call succeeded.
-    interface Error {
+interface Claim extends (Notifiable) {
+    resource @0 () -> ( resource :Resource );
+    # Pointer back to the resource this claim comes from.  Primarily useful when restoring persisted
+    # claims or restoring after a connection failure.
 
-    }
+    traits @1 () -> Map(OID, AnyPointer);
+
+    disown @2 ();
+    # Disown this claim
 }
 
 interface Lock extends (Claim) {
diff --git a/notify.capnp b/notify.capnp
index 346d9e2..46b78ed 100644
--- a/notify.capnp
+++ b/notify.capnp
@@ -3,19 +3,24 @@
 using CSharp = import "programming_language/csharp.capnp";
 $CSharp.namespace("FabAccessAPI.Schema");
 
-using import "state.capnp".State;
-using import "state.capnp".Update;
+using import "resource.capnp".Resource;
+using import "utils.capnp".OID;
+using import "utils.capnp".Map;
 
-interface Notifyable {
+interface Notifiable {
+    traits @0 () -> Map(OID, AnyPointer);
+}
+
+interface Notify(State, Update) {
     state @0 () -> ( state :State );
     # Returns the current state of a resource.
 
-    subscribe @1 ( subscriber :Subscriber ) -> ( subscription :Subscription );
+    subscribe @1 ( subscriber :Subscriber(Update) ) -> ( subscription :Subscription );
     # Subscribe to state updates. The passed in `subscriber` is an interface implemented on the
     # client side that a server calls to send update notifications.
 }
 
-interface Subscriber {
+interface Subscriber(Update) {
     update @0 ( update :Update ) -> ();
     # Called by a server when a new state was produced for this resource.  This method MAY not be
     # called when a resource was updated but did not change its state.  A server will only ever have
diff --git a/resource.capnp b/resource.capnp
index 6285712..d21116c 100644
--- a/resource.capnp
+++ b/resource.capnp
@@ -4,57 +4,82 @@ using CSharp = import "programming_language/csharp.capnp";
 $CSharp.namespace("FabAccessAPI.Schema");
 
 using import "persistent.capnp".Persistent;
-using import "notify.capnp".Notifyable;
+using import "notify.capnp".Notifiable;
 using import "interest.capnp".Interestable;
 using import "claim.capnp".Claimable;
 using import "claim.capnp".Lockable;
 
 using import "utils.capnp".OID;
 using import "utils.capnp".L10NString;
+using import "utils.capnp".Map;
 
-interface Resource extends (Persistent) {
+struct Resource {
     # BFFH's smallest unit of a physical or abstract "thing".  A resource can be as simple and
     # physical as a table, as complex as a PCB production line or as abstract as "people with
     # specific know-how are present".
 
-    describe @0 () -> Description;
-    # Return information about this resource.  This information is usually rather static, but may
-    # change between calls.
+    description @0 :Describable;
 
-    caps @1 () -> ( notify :Notifyable, interest :Interestable, claim :Claimable, lock :Lockable );
-    # return the capabilities an user has for this resource.
-    # `notify`: NULL if the user does not have permission to read this resource, or if this resource
-    #           is not notifiable
-    # `interest`: NULL if this resource is not interestable or the user does not have permission to
-    #             set interests for this resource.
-    # `claim`: NULL if the user does not have permission to write to this resource, or if this
-    #          resource type does not support claiming.
-    # `lock`: NULL if the user does not have permission to manage this resource, or if this resource
-    #         type does not support claiming or locking.
+    notify @1 :Notifiable;
+    # NULL if the user does not have permission to read this resource, or if this resource is not
+    # notifiable
+
+    interest @2 :Interestable;
+    # NULL if this resource is not interestable or the user does not have permission to set
+    # interests for this resource.
+
+    claim @3 :Claimable;
+    # NULL if the user does not have permission to write to this resource, or if this resource type
+    # does not support claiming.
+
+    lock @4 :Lockable;
+    # NULL if the user does not have permission to manage this resource, or if this resource type
+    # does not support claiming or locking.
+}
+
+interface Describable {
+    description @0 () -> Description;
+    # Return information about this resource.  This information is usually static and does not
+    # change between calls.
 }
 
 struct Description {
-    types @0 :List(OID);
-    # The 'type' of Resource.  Each OID in the list specifies certain behaviours that this Resource
-    # follows.
+    identifier @0 :Text;
+    # The unique identifier for this resource
 
-    urn @1 :Text;
-    # The URN of this resource.
-
-    category @2 :Text;
-    # A category this resource belongs to.  If a resource was not assigned a category this is NULL.
-
-    name @3 :L10NString;
+    name @1 :L10NString;
     # A human-facing name for this resource.  A name should be short and recognizable, and is meant
     # as the primary identifier for users to find a resource.
 
-    description @4 :L10NString;
+    description @2 :L10NString;
     # A human-facing description for this resource.  Descriptions are longer-form text that give
     # additional information about a resource beyond a name.  They are meant to provide either
     # further identifying information or important information that users should be actively shown
     # when selecting this resource.
 
-    wiki @5 :Text;
-    # An URI to further detailed information about this resource, e.g. in a wiki.  This SHOULD be an
-    # http or https URL.
+    types @3 :List(OID);
+    # The 'type' of Resource.  Each OID in the list specifies certain behaviours that this Resource
+    # follows.
+
+    category @4 :Category;
+    # A category this resource belongs to. If a resource was not assigned a category this is empty,
+    # see the definition of [`Category`](struct::Category) for details.
+
+    metadata @5 :Map(Text, Text);
+    # Metadata associated with this resource.  This can be things like links to wikis or similar.
+    # Common keys are pre-defined as constants in this file.
 }
+
+struct Category {
+    # A category this resource belongs to.
+
+    id @0 :Data;
+    # An unique ID for this category.  If a resource was not assigned a category this is NULL.
+
+    name @1 :L10NString;
+    # A human-facing name for this category.
+}
+
+const metadataWiki :Text = "wiki";
+# An URI to further detailed information about this resource, e.g. in a wiki.  This SHOULD be an
+# https URL.
diff --git a/resources.capnp b/resources.capnp
index b71874e..99798e8 100644
--- a/resources.capnp
+++ b/resources.capnp
@@ -3,13 +3,12 @@
 using CSharp = import "programming_language/csharp.capnp";
 $CSharp.namespace("FabAccessAPI.Schema");
 
-using import "/capnp/rpc.capnp".SturdyRef;
-
 using import "resource.capnp".Resource;
+using import "claim.capnp".Claim;
 
 interface Resources {
-    restore @0 ( sturdy :SturdyRef ) -> ( resources :Resource );
-    # Restore a previously saved SturdyRef pointing to a Resource
+    claimed @0 () -> ( claimed :List(Claim) );
+    # Returns the list of valid claims the session owner of this `Resources` currently has.
 
     list @1 () -> ( resources :List(Resource) );
 
diff --git a/state.capnp b/state.capnp
index b1a9a78..f9aa7d1 100644
--- a/state.capnp
+++ b/state.capnp
@@ -7,6 +7,8 @@ using import "utils.capnp".OID;
 
 interface State {
     get @0 ( oid :OID ) -> ( val :AnyPointer );
+    # Return the value for the field specified by `oid`.
+    # If the field is not set or the resource does not support a field with that OID the returned `val` is NULL.
 }
 
 struct UpdateValue {
diff --git a/utils.capnp b/utils.capnp
index 217117b..befac02 100644
--- a/utils.capnp
+++ b/utils.capnp
@@ -61,3 +61,23 @@ using OID = Data;
 # a rather efficient encoding since almost all edges of the OID tree are smaller than 128 and thus
 # encode into one byte.  X.208 does *not* limit the size of nodes! However, a reasonable size limit
 # is 128 bit per node, which is the size of the UUID nodes in the `2.25` subtree.
+
+struct Map(Key, Value) {
+    # Generic Key-Value-Map
+
+    entries @0 :List(Entry);
+    struct Entry {
+        key @0 :Key;
+        value @1 :Value;
+    }
+}
+
+struct Fallible(Ok, Error) {
+    union {
+        ok @0 :Ok;
+        err :group {
+            error @1 :Error;
+            description @2 :L10NString;
+        }
+    }
+}