diff --git a/src/prefixmaps/ingest/ingest_w3id.py b/src/prefixmaps/ingest/ingest_w3id.py
index 7a8bdf9..324bf20 100644
--- a/src/prefixmaps/ingest/ingest_w3id.py
+++ b/src/prefixmaps/ingest/ingest_w3id.py
@@ -2,21 +2,23 @@
 
 from prefixmaps.datamodel.context import Context
 
-API_LIST_CALL = "https://api.github.com/repos/perma-id/w3id.org/git/trees/master"
+API_LIST_CALL = "https://api.github.com/repos/perma-id/w3id.org/git/trees/master:ids"
 
 
 def from_w3id() -> Context:
     """
     Creates a Context from the https://github.com/perma-id/w3id.org/.
 
+    Each directory under ``ids/`` in that repository is served as ``https://w3id.org/<name>/``.
+
     :return:
     """
     import requests
 
     r = requests.get(API_LIST_CALL)
-    results = r.json()
     if r.status_code != 200:
-        raise ValueError(results.message)
+        raise ValueError(f"{API_LIST_CALL} returned {r.status_code}: {r.text}")
+    results = r.json()
     if results["truncated"]:
         raise ValueError("truncated results")
     ctxt = Context("w3id")