diff --git a/src/mcp/mcp.c b/src/mcp/mcp.c
index 26b232d20..d3aa3bf3d 100644
--- a/src/mcp/mcp.c
+++ b/src/mcp/mcp.c
@@ -1875,7 +1875,10 @@ static char *handle_get_architecture(cbm_mcp_server_t *srv, const char *args) {
     }
 
     cbm_schema_info_t schema = {0};
-    cbm_store_get_schema(store, project, &schema);
+    /* Counts-only: this handler renders label/type counts but never property
+     * keys, and full key discovery json_each-scans every row (seconds-to-
+     * minutes on multi-million-node graphs). */
+    cbm_store_get_schema_counts(store, project, &schema);
 
     cbm_architecture_info_t arch = {0};
     cbm_store_get_architecture(store, project, aspects_strs_count > 0 ? aspects_strs : NULL,
diff --git a/src/store/store.c b/src/store/store.c
index 09bb76028..c237332e2 100644
--- a/src/store/store.c
+++ b/src/store/store.c
@@ -295,6 +295,12 @@ static int create_user_indexes(cbm_store_t *s) {
         "CREATE INDEX IF NOT EXISTS idx_edges_target_type ON edges(project, target_id, type);"
         "CREATE INDEX IF NOT EXISTS idx_edges_source_type ON edges(project, source_id, type);"
         "CREATE INDEX IF NOT EXISTS idx_edges_url_path ON edges(project, url_path_gen);";
+    /* NOTE: a partial expression index on json_extract(properties,'$.is_entry_point')
+     * was tried for arch_entry_points and REVERTED: json_extract in an index WHERE
+     * aborts CREATE INDEX (and thus store open) on any row whose properties JSON is
+     * malformed — and pre-fix databases contain such rows (see
+     * pipeline_def_props_valid_json_when_oversized). Revisit only with a
+     * json_valid()-guarded expression once legacy DBs have aged out. */
     return exec_sql(s, sql);
 }
 
@@ -2897,7 +2903,11 @@ static void schema_discover_props(sqlite3 *db, const char *sql, const char *proj
     *out_count = pn;
 }
 
-int cbm_store_get_schema(cbm_store_t *s, const char *project, cbm_schema_info_t *out) {
+/* with_props=false skips the per-label/per-type JSON property-key discovery:
+ * those json_each() scans walk EVERY row of each label/type (minutes-scale on
+ * multi-million-node graphs) and get_architecture only needs the counts. */
+static int get_schema_impl(cbm_store_t *s, const char *project, cbm_schema_info_t *out,
+                           bool with_props) {
     memset(out, 0, sizeof(*out));
     if (!s || !s->db) {
         return CBM_NOT_FOUND;
@@ -2950,7 +2960,7 @@ int cbm_store_get_schema(cbm_store_t *s, const char *project, cbm_schema_info_t
     }
 
     /* Node label property keys: base columns + distinct JSON property keys per label */
-    {
+    if (with_props) {
         static const char *node_base_cols[] = {"name", "qualified_name", "file_path", "start_line",
                                                "end_line"};
         const char *prop_sql = "SELECT DISTINCT je.key "
@@ -3018,7 +3028,7 @@ int cbm_store_get_schema(cbm_store_t *s, const char *project, cbm_schema_info_t
     }
 
     /* Edge type property keys: base columns + distinct JSON property keys per type */
-    {
+    if (with_props) {
         static const char *edge_base_cols[] = {"source_id", "target_id"};
         const char *prop_sql = "SELECT DISTINCT je.key "
                                "FROM edges, json_each(edges.properties) AS je "
@@ -3038,6 +3048,14 @@ int cbm_store_get_schema(cbm_store_t *s, const char *project, cbm_schema_info_t
     return CBM_STORE_OK;
 }
 
+int cbm_store_get_schema(cbm_store_t *s, const char *project, cbm_schema_info_t *out) {
+    return get_schema_impl(s, project, out, true);
+}
+
+int cbm_store_get_schema_counts(cbm_store_t *s, const char *project, cbm_schema_info_t *out) {
+    return get_schema_impl(s, project, out, false);
+}
+
 void cbm_store_schema_free(cbm_schema_info_t *out) {
     if (!out) {
         return;
diff --git a/src/store/store.h b/src/store/store.h
index a20f432de..26b09a5c2 100644
--- a/src/store/store.h
+++ b/src/store/store.h
@@ -425,6 +425,11 @@ int cbm_deduplicate_hops(const cbm_node_hop_t *hops, int hop_count, cbm_node_hop
 
 int cbm_store_get_schema(cbm_store_t *s, const char *project, cbm_schema_info_t *out);
 
+/* Like cbm_store_get_schema but skips per-label/per-type JSON property-key
+ * discovery (json_each scans over every row) — for callers that only need
+ * label/type counts, e.g. get_architecture. */
+int cbm_store_get_schema_counts(cbm_store_t *s, const char *project, cbm_schema_info_t *out);
+
 /* Free a schema info's allocated memory. */
 void cbm_store_schema_free(cbm_schema_info_t *out);