diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0234a98a..42bb6738 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 - Idents run in parallel when using parallel processor (issue #208)
 - Fix wrong input order on nested resolvers (issue #205)
 - Fix `pf.eql/map-select` case on map container at query
+- Fix spec for `pco/?`
 
 ## [2023.08.22-alpha]
 - BREAKING: `::p.error/missing-output` is now converged to `::p.error/attribute-missing` (issue #149)
diff --git a/src/main/com/wsscode/pathom3/attribute.cljc b/src/main/com/wsscode/pathom3/attribute.cljc
index 7e46600a..28c477d5 100644
--- a/src/main/com/wsscode/pathom3/attribute.cljc
+++ b/src/main/com/wsscode/pathom3/attribute.cljc
@@ -5,4 +5,7 @@
     [com.fulcrologic.guardrails.core :refer [<- => >def >defn >fdef ? |]]))
 
 (>def ::attribute keyword?)
+(>def ::parameterized-attribute (s/and seq? (s/cat :attr ::attribute :params (s/? ::params))))
+(>def ::attribute-maybe-parameterized (s/or :plain-attr ::attribute :parameterized ::parameterized-attribute))
+
 (>def ::attributes-set (s/coll-of ::attribute :kind set?))
diff --git a/src/main/com/wsscode/pathom3/connect/operation.cljc b/src/main/com/wsscode/pathom3/connect/operation.cljc
index 6e02ce08..2c5adc8c 100644
--- a/src/main/com/wsscode/pathom3/connect/operation.cljc
+++ b/src/main/com/wsscode/pathom3/connect/operation.cljc
@@ -128,7 +128,7 @@
 (>defn ?
   "Make an attribute optional"
   [attr]
-  [::p.attr/attribute => any?]
+  [::p.attr/attribute-maybe-parameterized => any?]
   (eql/update-property-param attr assoc ::optional? true))
 
 (>defn operation-config [operation]