diff --git a/client b/client
index 382c704..37e12ef 160000
--- a/client
+++ b/client
@@ -1 +1 @@
-Subproject commit 382c704a08d8c18a355432983e3ed0aaade0e902
+Subproject commit 37e12efd46b3539575b47f057cefd5f3c49d1ac8
diff --git a/common/src/grpc_error.rs b/common/src/grpc_error.rs
new file mode 100644
index 0000000..9a67d9e
--- /dev/null
+++ b/common/src/grpc_error.rs
@@ -0,0 +1,2 @@
+pub const ERROR_REASON_METADATA_KEY: &str = "komp-ac-error-reason";
+pub const COMPUTED_VALUE_MISMATCH_REASON: &str = "computed-value-mismatch";
diff --git a/common/src/lib.rs b/common/src/lib.rs
index a835544..edba9b1 100644
--- a/common/src/lib.rs
+++ b/common/src/lib.rs
@@ -1,6 +1,7 @@
 // common/src/lib.rs
 
 pub mod search;
+pub mod grpc_error;
 
 pub mod proto {
     pub mod komp_ac {
diff --git a/server b/server
index 40d76eb..8c46130 160000
--- a/server
+++ b/server
@@ -1 +1 @@
-Subproject commit 40d76eb75c2b1b2027bc2a3d19330800e819e63c
+Subproject commit 8c461303c3430b220109ae39c619c3d3fc90e793