diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,15 @@
 # Changelog
 
+## [Unreleased]
+
+## 0.8.0.1 — 2026-10-05
+
+### Changed
+
+- Admit effectful 2.7 alongside the existing supported range: `effectful <2.8` and
+  `effectful-core >=2.5 && <2.7 || >=2.7.1.1 && <2.8`. Exclude the
+  effectful-core 2.7.0.0–2.7.1.0 performance regression. Bounds only; no source changed.
+
 ## 0.8.0.0 — 2026-09-26
 
 ### Breaking Changes
diff --git a/kioku-core.cabal b/kioku-core.cabal
--- a/kioku-core.cabal
+++ b/kioku-core.cabal
@@ -1,6 +1,6 @@
 cabal-version: 3.0
 name: kioku-core
-version: 0.8.0.0
+version: 0.8.0.1
 synopsis: Reusable agent memory runtime
 description:
   Core runtime for kioku. M1 establishes the application effect stack; later
@@ -123,8 +123,8 @@
     contravariant-extras >=0.3 && <0.4,
     crypton ^>=1.1.4,
     directory >=1.3 && <1.4,
-    effectful >=2.5 && <2.7,
-    effectful-core >=2.5 && <2.7,
+    effectful >=2.5 && <2.8,
+    effectful-core >=2.5 && <2.7 || >=2.7.1.1 && <2.8,
     filepath >=1.4 && <1.6,
     generic-lens >=2.2 && <2.4,
     hasql >=1.6 && <1.11,
@@ -134,7 +134,7 @@
     keiki ^>=0.9.1.0,
     keiro ^>=0.19.0.0,
     keiro-core ^>=0.19.0.0,
-    kioku-api ^>=0.8.0.0,
+    kioku-api ^>=0.8.0.1,
     kiroku-store ^>=0.9.0.1,
     lens >=5.2 && <5.4,
     mmzk-typeid >=0.7 && <0.8,
@@ -193,17 +193,17 @@
     containers >=0.6,
     contravariant >=1.5,
     directory >=1.3,
-    effectful >=2.5,
-    effectful-core >=2.5,
+    effectful >=2.5 && <2.8,
+    effectful-core >=2.5 && <2.7 || >=2.7.1.1 && <2.8,
     filepath >=1.4,
     generic-lens >=2.2 && <2.4,
     hasql >=1.6,
     hasql-transaction >=1.0,
     keiro ^>=0.19.0.0,
     keiro-core ^>=0.19.0.0,
-    kioku-api ^>=0.8.0.0,
-    kioku-core ^>=0.8.0.0,
-    kioku-migrations:test-support ^>=0.8.0.0,
+    kioku-api ^>=0.8.0.1,
+    kioku-core ^>=0.8.0.1,
+    kioku-migrations:test-support ^>=0.8.0.1,
     kiroku-store ^>=0.9.0.1,
     lens >=5.2,
     shibuya-core ^>=0.10.0.0,