diff --git a/cylc/flow/prerequisite.py b/cylc/flow/prerequisite.py
index 94221fd790..1edf7aa1da 100644
--- a/cylc/flow/prerequisite.py
+++ b/cylc/flow/prerequisite.py
@@ -74,7 +74,6 @@ def coerce(tuple_: AnyPrereqMessage) -> 'PrereqMessage':
     'satisfied naturally',
     'satisfied from database',
     'satisfied by skip mode',
-    'satisfied by simulation mode',
     'force satisfied',
     False
 ]
@@ -104,12 +103,6 @@ class Prerequisite:
     SATISFIED_TEMPLATE = 'bool(self._satisfied[("%s", "%s", "%s")])'
     MESSAGE_TEMPLATE = r'%s/%s %s'
 
-    DEP_STATE_SATISFIED: SatisfiedState = 'satisfied naturally'
-    DEP_STATE_SATISFIED_BY = 'satisfied by {} mode'
-    DEP_STATE_OVERRIDDEN = 'force satisfied'
-    DEP_STATE_UNSATISFIED = False
-    SATISFIED_MODE_RE = re.compile(r'satisfied by .* mode')
-
     def __init__(self, point: 'PointBase'):
         # The cycle point to which this prerequisite belongs.
         # cylc.flow.cycling.PointBase
@@ -263,8 +256,9 @@ def _eval_satisfied(self) -> bool:
         return res
 
     def satisfy_me(
-        self, outputs: Iterable['Tokens'],
-        mode: Optional[RunMode] = RunMode.LIVE
+        self,
+        outputs: Iterable['Tokens'],
+        mode: Optional[RunMode] = None,
     ) -> 'Set[Tokens]':
         """Attempt to satisfy me with given outputs.
 
@@ -272,15 +266,10 @@ def satisfy_me(
         Return outputs that match.
 
         """
-        satisfied_message: SatisfiedState
-
-        if mode and mode != RunMode.LIVE:
-            # RunMode.value actually actually restricts the results in
-            # SatisfiedState, but MyPy does not recognize this.
-            satisfied_message = self.DEP_STATE_SATISFIED_BY.format(
-                RunMode(mode).value)   # type: ignore
-        else:
-            satisfied_message = self.DEP_STATE_SATISFIED
+        satisfied_message: SatisfiedState = (
+            'satisfied by skip mode' if mode == RunMode.SKIP
+            else 'satisfied naturally'
+        )
         valid = set()
         for output in outputs:
             prereq = PrereqMessage(
diff --git a/tests/integration/test_task_pool.py b/tests/integration/test_task_pool.py
index 6af4f92813..483b67cad2 100644
--- a/tests/integration/test_task_pool.py
+++ b/tests/integration/test_task_pool.py
@@ -645,8 +645,7 @@ def list_tasks(schd):
                 ('1', 'z', 'waiting'),
             ],
             [
-                {('1', 'a', 'succeeded'):
-                    'satisfied by simulation mode'},
+                {('1', 'a', 'succeeded'): 'satisfied naturally'},
                 {('1', 'b', 'succeeded'): False},
                 {('1', 'c', 'succeeded'): False},
             ],
@@ -674,8 +673,7 @@ def list_tasks(schd):
                 ('1', 'z', 'waiting'),
             ],
             [
-                {('1', 'a', 'succeeded'):
-                    'satisfied by simulation mode'},
+                {('1', 'a', 'succeeded'): 'satisfied naturally'},
                 {('1', 'b', 'succeeded'): False},
             ],
             id='removed'
@@ -770,8 +768,7 @@ async def test_restart_prereqs(
                 ('1', 'z', 'waiting'),
             ],
             [
-                {('1', 'a', 'succeeded'):
-                    'satisfied by simulation mode'},
+                {('1', 'a', 'succeeded'): 'satisfied naturally'},
                 {('1', 'b', 'succeeded'): False},
                 {('1', 'c', 'succeeded'): False},
             ],
@@ -799,8 +796,7 @@ async def test_restart_prereqs(
                 ('1', 'z', 'waiting'),
             ],
             [
-                {('1', 'a', 'succeeded'):
-                    'satisfied by simulation mode'},
+                {('1', 'a', 'succeeded'): 'satisfied naturally'},
                 {('1', 'b', 'succeeded'): False},
             ],
             id='removed'
@@ -899,7 +895,7 @@ async def _test_restart_prereqs_sat():
         for prereq in task_c.state.prerequisites
         for key, satisfied in prereq.items()
     ) == [
-        ('1', 'a', 'succeeded', 'satisfied by simulation mode'),
+        ('1', 'a', 'succeeded', 'satisfied naturally'),
         ('1', 'b', 'succeeded', 'satisfied from database')
     ]
 
@@ -916,7 +912,7 @@ async def _test_restart_prereqs_sat():
         for prereq in task_c_prereqs
         for condition in prereq.conditions
     ) == [
-        ('1/a', True, 'satisfied by simulation mode'),
+        ('1/a', True, 'satisfied naturally'),
         ('1/b', True, 'satisfied from database'),
     ]
 
@@ -2255,7 +2251,7 @@ async def list_data_store():
             'c': 'wall_clock(trigger_time=946688400)',
         }
 
-        
+
 async def test_trigger_unqueued(flow, scheduler, start):
     """Test triggering an unqueued active task.
 
@@ -2320,7 +2316,7 @@ async def test_expire_dequeue_with_retries(flow, scheduler, start, expire_type):
 
     if expire_type == 'clock-expire':
         conf['scheduling']['special tasks'] = {'clock-expire': 'foo(PT0S)'}
-        method = lambda schd: schd.pool.clock_expire_tasks() 
+        method = lambda schd: schd.pool.clock_expire_tasks()
     else:
         method = lambda schd: schd.pool.set_prereqs_and_outputs(
             ['2000/foo'], prereqs=[], outputs=['expired'], flow=['1']