diff --git a/tests/ulm-with-contract/erc_20_token.1.run b/tests/ulm-with-contract/erc_20_token.1.run
index b3388e7..94e4dd0 100644
--- a/tests/ulm-with-contract/erc_20_token.1.run
+++ b/tests/ulm-with-contract/erc_20_token.1.run
@@ -8,11 +8,11 @@ list_mock GetAccountStorageHook ( storageKey("balances", 1010101_u160:u160) ) ul
 list_mock SetAccountStorageHook ( storageKey("balances", 1010101_u160:u160) , 9900_u256 ) ulmNoResult();
 list_mock GetAccountStorageHook ( storageKey("balances", 2020202_u160:u160) ) ulmIntResult(0, u256);
 list_mock SetAccountStorageHook ( storageKey("balances", 2020202_u160:u160) , 100_u256 ) ulmNoResult();
-list_mock Log3Hook ( 100389287136786176327247604509743168900146139575972864366142685224231313322991 , 1010101 , 2020202 , b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00d" ) ulmNoResult();
+list_mock Log3Hook ( eventSignature("Transfer(address,address,uint256)") , 1010101 , 2020202 , encodeValues(100_u256:u256) ) ulmNoResult();
 list_mock GetAccountStorageHook ( storageKey("balances", 1010101_u160:u160) ) ulmIntResult(9900, u256);
 list_mock GetAccountStorageHook ( storageKey("balances", 2020202_u160:u160) ) ulmIntResult(100, u256);
 list_mock SetAccountStorageHook ( storageKey("allowances", 1010101_u160:u160, 3030303_u160:u160) , 200_u256 ) ulmNoResult();
-list_mock Log3Hook ( 63486140976153616755203102783360879283472101686154884697241723088393386309925 , 1010101 , 3030303 , b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xc8" ) ulmNoResult();
+list_mock Log3Hook ( eventSignature("Approval(address,address,uint256)") , 1010101 , 3030303 , encodeValues(200_u256:u256) ) ulmNoResult();
 list_mock GetAccountStorageHook ( storageKey("allowances", 1010101_u160:u160, 3030303_u160:u160) ) ulmIntResult(200, u256);
 list_mock SetAccountStorageHook ( storageKey("allowances", 1010101_u160:u160, 3030303_u160:u160) , 0_u256 ) ulmNoResult();
 list_mock GetAccountStorageHook ( storageKey("balances", 1010101_u160:u160) ) ulmIntResult(9900, u256);
@@ -20,7 +20,7 @@ list_mock GetAccountStorageHook ( storageKey("balances", 1010101_u160:u160) ) ul
 list_mock SetAccountStorageHook ( storageKey("balances", 1010101_u160:u160) , 9700_u256 ) ulmNoResult();
 list_mock GetAccountStorageHook ( storageKey("balances", 2020202_u160:u160) ) ulmIntResult(100, u256);
 list_mock SetAccountStorageHook ( storageKey("balances", 2020202_u160:u160) , 300_u256 ) ulmNoResult();
-list_mock Log3Hook ( 100389287136786176327247604509743168900146139575972864366142685224231313322991 , 1010101 , 2020202 , b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xc8" ) ulmNoResult();
+list_mock Log3Hook ( eventSignature("Transfer(address,address,uint256)") , 1010101 , 2020202 , encodeValues(200_u256:u256) ) ulmNoResult();
 list_mock GetAccountStorageHook ( storageKey("balances", 1010101_u160:u160) ) ulmIntResult(9700, u256);
 list_mock GetAccountStorageHook ( storageKey("balances", 2020202_u160:u160) ) ulmIntResult(300, u256);
 
diff --git a/ulm-semantics/main/hooks/ulm.md b/ulm-semantics/main/hooks/ulm.md
index af09a70..c6b06f6 100644
--- a/ulm-semantics/main/hooks/ulm.md
+++ b/ulm-semantics/main/hooks/ulm.md
@@ -8,8 +8,6 @@ module ULM-SEMANTICS-HOOKS-ULM-SYNTAX
                       | CallerHook()
                       | SetAccountStorageHook(Int, Int)
                       | GetAccountStorageHook(Int)
-                      // TODO: Build mocks for all the hooks below in a meaningful
-                      // way in tests (right now we just use opaque values).
                       | Log0Hook(Bytes)
                       | Log1Hook(Int, Bytes)
                       | Log2Hook(Int, Int, Bytes)
diff --git a/ulm-semantics/test/execution.md b/ulm-semantics/test/execution.md
index 4b3df80..6f6c0c6 100644
--- a/ulm-semantics/test/execution.md
+++ b/ulm-semantics/test/execution.md
@@ -44,8 +44,11 @@ module ULM-TEST-SYNTAX
 
     syntax UlmTestHook  ::= SetAccountStorageHook(StorageKey, Expression)  [seqstrict, result(TestResult)]
                           | GetAccountStorageHook(StorageKey)  [seqstrict, result(TestResult)]
+                          | Log3Hook(EventSignature, Int, Int, EncodeValues)  [seqstrict(1, 4), result(TestResult)]
 
     syntax StorageKey ::= storageKey(String, EncodeArgs)
+    syntax EventSignature ::= eventSignature(String)
+    syntax EncodeValues ::= encodeValues(EncodeArgs)
 endmodule
 
 module ULM-TEST-EXECUTION
@@ -68,7 +71,7 @@ module ULM-TEST-EXECUTION
 
     syntax UlmTestHook  ::= #SetAccountStorageHook(Int, IntOrError)
                           | #GetAccountStorageHook(Int)
-
+                          | #Log3Hook(Int, Int, Int, Bytes)
     syntax Mockable ::= UlmHook
 
     syntax BytesOrError ::= extractCallSignature(EncodeCall)  [function, total]
@@ -208,9 +211,12 @@ module ULM-TEST-EXECUTION
     syntax Bool ::= isTestResult(K) [symbol(isTestResult), function]
     rule isTestResult(_:K) => false  [owise]
     rule isTestResult(evaluatedStorageKey(_:Bytes)) => true
+    rule isTestResult(evaluatedEventSignature(_:Int)) => true
+    rule isTestResult(encodedValues(_:Bytes)) => true
     rule isTestResult(_:PtrValue) => true
     rule isTestResult(#SetAccountStorageHook(_:Int, _:Int)) => true
     rule isTestResult(#GetAccountStorageHook(_:Int)) => true
+    rule isTestResult(#Log3Hook(_:Int, _:Int, _:Int, _:Bytes)) => true
 
     syntax StorageKey ::= storageKey(NonEmptyStatementsOrError)
                         | storageKey(Expression)  [strict(1)]
@@ -232,6 +238,30 @@ module ULM-TEST-EXECUTION
     rule storageKey(ptrValue(_, u64(BytesId))) => storageKey(ulmBytesId(BytesId))
     rule storageKey(ulmBytesValue(B:Bytes)) => evaluatedStorageKey(B)
 
+    syntax EventSignature ::= evaluatedEventSignature(Int)
+    rule eventSignature(Signature:String)
+        => evaluatedEventSignature(Bytes2Int(Keccak256raw(String2Bytes(Signature)), BE, Unsigned))
+
+    syntax EncodeValues ::= encodeValues(NonEmptyStatementsOrError)
+                          | encodeValues(Expression)  [strict(1)]
+                          | encodeValues(UlmExpression)  [strict(1)]
+                          | encodedValues(Bytes)
+    rule encodeValues(Args:EncodeArgs)
+        => encodeValues
+            ( concat
+                (   let buffer_id = :: bytes_hooks :: empty( .CallParamsList );
+                    .NonEmptyStatements
+                ,   encodeStatements
+                        ( buffer_id
+                        , encodeArgsToEncodeValues(Args)
+                        )
+                )
+            )
+    rule encodeValues(Statements:NonEmptyStatements)
+        =>  encodeValues({.InnerAttributes Statements buffer_id })
+    rule encodeValues(ptrValue(_, u64(BytesId))) => encodeValues(ulmBytesId(BytesId))
+    rule encodeValues(ulmBytesValue(B:Bytes)) => encodedValues(B)
+
     rule SetAccountStorageHook(evaluatedStorageKey(B:Bytes), ptrValue(_, Value:Value))
         => #SetAccountStorageHook
                 ( Bytes2Int(Keccak256raw(B), BE, Unsigned)
@@ -257,6 +287,18 @@ module ULM-TEST-EXECUTION
             GetAccountStorageHook(Key)
             Result
 
+    rule Log3Hook(evaluatedEventSignature(I:Int), A:Int, C:Int, encodedValues(B2:Bytes))
+        => #Log3Hook
+                ( I
+                , A
+                , C
+                , B2
+                )
+    rule list_mock #Log3Hook(V1:Int, V2:Int, V3:Int, B:Bytes) Result:UlmHookResult
+        => list_mock
+            Log3Hook(V1, V2, V3, B)
+            Result
+
     // This may seem stupid, but it's a workaround for
     // https://github.com/runtimeverification/k/issues/4683
     rule isKResult(X) => true requires isTestResult(X)