diff --git a/config/migrations/2026/20260926120000-add-chat-attachment-types-codelist.ttl b/config/migrations/2026/20260926120000-add-chat-attachment-types-codelist.ttl
new file mode 100644
index 0000000..1fe128f
--- /dev/null
+++ b/config/migrations/2026/20260926120000-add-chat-attachment-types-codelist.ttl
@@ -0,0 +1,29 @@
+@prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
+@prefix mu:   <http://mu.semte.ch/vocabularies/core/> .
+
+# The bijlagen of the report assistant get a dct:type. Two types for now:
+# the specification of the report, and the executed report with its results.
+
+<http://lblod.data.gift/concept-schemes/f1103789-c5c9-406e-8079-be6c833d0d69>
+  rdf:type skos:ConceptScheme ;
+  mu:uuid "f1103789-c5c9-406e-8079-be6c833d0d69" ;
+  skos:prefLabel "Bijlagetypen rapportassistent"@nl, "Report assistant attachment types"@en ;
+  skos:definition "Types bijlage bij berichten van de rapportassistent: rapport specificaties en uitgevoerde rapporten."@nl ;
+  skos:hasTopConcept <http://lblod.data.gift/concepts/6693014e-7b7d-448c-bb24-80c9758521f3>,
+      <http://lblod.data.gift/concepts/28d97698-e219-4a92-bdbd-7ab367a7524e> .
+
+<http://lblod.data.gift/concepts/6693014e-7b7d-448c-bb24-80c9758521f3>
+  rdf:type skos:Concept ;
+  mu:uuid "6693014e-7b7d-448c-bb24-80c9758521f3" ;
+  skos:prefLabel "Rapportspecificatie"@nl, "Report specification"@en ;
+  skos:altLabel "Query spec"@nl, "Query spec"@en ;
+  skos:definition "De specificatie die vastlegt welk rapport gemaakt wordt: filter en kolommen."@nl ;
+  skos:inScheme <http://lblod.data.gift/concept-schemes/f1103789-c5c9-406e-8079-be6c833d0d69> .
+
+<http://lblod.data.gift/concepts/28d97698-e219-4a92-bdbd-7ab367a7524e>
+  rdf:type skos:Concept ;
+  mu:uuid "28d97698-e219-4a92-bdbd-7ab367a7524e" ;
+  skos:prefLabel "Uitgevoerd rapport"@nl, "Executed report"@en ;
+  skos:definition "De resultaten van een rapport dat de rapportassistent heeft uitgevoerd."@nl ;
+  skos:inScheme <http://lblod.data.gift/concept-schemes/f1103789-c5c9-406e-8079-be6c833d0d69> .
diff --git a/config/resources/chat-domain.json b/config/resources/chat-domain.json
index 4b50668..9b3636c 100644
--- a/config/resources/chat-domain.json
+++ b/config/resources/chat-domain.json
@@ -132,7 +132,7 @@
         },
         "attachments": {
           "predicate": "as:attachment",
-          "target": "chat-documents",
+          "target": "file",
           "cardinality": "many"
         }
       },
@@ -146,25 +146,6 @@
       "features": ["include-uri"],
       "new-resource-base": "http://data.lblod.info/id/chat-messages/"
     },
-    "chat-documents": {
-      "class": "as:Document",
-      "attributes": {
-        "name": {
-          "type": "string",
-          "predicate": "as:name"
-        },
-        "media-type": {
-          "type": "string",
-          "predicate": "as:mediaType"
-        },
-        "url": {
-          "type": "string",
-          "predicate": "as:url"
-        }
-      },
-      "features": ["include-uri"],
-      "new-resource-base": "http://data.lblod.info/id/chat-documents/"
-    },
     "chat-agents": {
       "class": "prov:SoftwareAgent",
       "attributes": {
diff --git a/config/resources/domain.lisp b/config/resources/domain.lisp
index 2e93235..76ee8a0 100644
--- a/config/resources/domain.lisp
+++ b/config/resources/domain.lisp
@@ -16,9 +16,9 @@
 
 (read-domain-file "domain.json")
 (read-domain-file "auth.json")
+(read-domain-file "file.json")
 (read-domain-file "chat-domain.json")
 (read-domain-file "change-events.json")
-(read-domain-file "file.json")
 (read-domain-file "dcat.json")
 (read-domain-file "privacy-centric-service.json")
 (read-domain-file "job.json")