diff --git a/.schema/statemachine.json b/.schema/statemachine.json
index 9be4edd9..1798e523 100644
--- a/.schema/statemachine.json
+++ b/.schema/statemachine.json
@@ -16,6 +16,7 @@
       "type": "object"
     },
     "Condition": {
+      "additionalProperties": false,
       "description": "A condition in the state machine.",
       "properties": {
         "channel": {
@@ -38,6 +39,7 @@
       "type": "object"
     },
     "Conditions": {
+      "additionalProperties": false,
       "description": "A collection of conditions.",
       "patternProperties": {
         "^\\d+$": {
@@ -48,6 +50,7 @@
       "type": "object"
     },
     "GlobalCounter": {
+      "additionalProperties": false,
       "description": "A global counter in the state machine.",
       "properties": {
         "event": {
@@ -72,6 +75,7 @@
       "type": "object"
     },
     "GlobalCounters": {
+      "additionalProperties": false,
       "description": "A collection of global counters.",
       "patternProperties": {
         "^\\d+$": {
@@ -82,6 +86,7 @@
       "type": "object"
     },
     "GlobalTimer": {
+      "additionalProperties": false,
       "description": "A global timer in the state machine.",
       "properties": {
         "duration": {
@@ -100,6 +105,9 @@
         "channel": {
           "anyOf": [
             {
+              "description": "The channel affected by the global timer",
+              "minLength": 1,
+              "title": "Channel",
               "type": "string"
             },
             {
@@ -133,7 +141,7 @@
         },
         "loop": {
           "default": 0,
-          "description": "Whether the global timer is looping or not",
+          "description": "0 = off, 1 = loop until canceled or trial end, >1 = fixed number of iterations (max 255)",
           "maximum": 255,
           "minimum": 0,
           "title": "Loop Mode",
@@ -141,7 +149,7 @@
         },
         "loop_interval": {
           "default": 0.0,
-          "description": "The interval in seconds that the global timer is looping",
+          "description": "Delay in seconds between the end of a loop iteration and the start of the next",
           "minimum": 0.0,
           "title": "Loop Interval",
           "type": "number"
@@ -161,6 +169,7 @@
       "type": "object"
     },
     "GlobalTimers": {
+      "additionalProperties": false,
       "description": "A collection of global timers.",
       "patternProperties": {
         "^\\d+$": {
@@ -171,6 +180,7 @@
       "type": "object"
     },
     "State": {
+      "additionalProperties": false,
       "description": "A state in the state machine.",
       "properties": {
         "timer": {
@@ -207,6 +217,7 @@
       "type": "object"
     },
     "States": {
+      "additionalProperties": false,
       "description": "A collection of states.",
       "patternProperties": {
         "^(?!>)(?!exit$)(?!back$).+$": {
@@ -254,6 +265,7 @@
   },
   "$id": "https://raw.githubusercontent.com/int-brain-lab/bpod-core/main/.schema/statemachine.json",
   "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": false,
   "description": "Definition of a Bpod finite-state machine.",
   "properties": {
     "name": {
diff --git a/bpod_core/fsm.py b/bpod_core/fsm.py
index 3557eb11..5c380b16 100644
--- a/bpod_core/fsm.py
+++ b/bpod_core/fsm.py
@@ -173,7 +173,7 @@ def _validate_operator(v: Any, h: ValidatorFunctionWrapHandler) -> 'Operator':
 
 GlobalTimerChannel = Annotated[
     str,
-    msgspec.Meta(
+    Field(
         title='Channel',
         description='The channel affected by the global timer',
         min_length=1,
@@ -204,7 +204,10 @@ def _validate_operator(v: Any, h: ValidatorFunctionWrapHandler) -> 'Operator':
     int,
     Field(
         title='Loop Mode',
-        description='Whether the global timer is looping or not',
+        description=(
+            '0 = off, 1 = loop until canceled or trial end, >1 = fixed number '
+            'of iterations (max 255)'
+        ),
         default=0,
         ge=0,
         le=255,
@@ -215,7 +218,10 @@ def _validate_operator(v: Any, h: ValidatorFunctionWrapHandler) -> 'Operator':
     float,
     Field(
         title='Loop Interval',
-        description='The interval in seconds that the global timer is looping',
+        description=(
+            'Delay in seconds between the end of a loop iteration and the start of the '
+            'next'
+        ),
         default=0.0,
         ge=0.0,
     ),
@@ -343,9 +349,11 @@ def __init__(
         ) -> None: ...
 
 
-class State(BaseModel, validate_assignment=True, title='State'):
+class State(BaseModel, title='State'):
     """A state in the state machine."""
 
+    model_config = ConfigDict(validate_assignment=True, extra='forbid')
+
     timer: StateTimer = StateTimer()
     transitions: Transitions = Transitions()
     actions: Actions = Actions()
@@ -357,9 +365,11 @@ def __repr__(self) -> str:
         return f'{self.__class__.__name__}({values})'
 
 
-class GlobalTimer(BaseModel, validate_assignment=True, title='Global Timer'):
+class GlobalTimer(BaseModel, title='Global Timer'):
     """A global timer in the state machine."""
 
+    model_config = ConfigDict(validate_assignment=True, extra='forbid')
+
     duration: GlobalTimerDuration
     onset_delay: GlobalTimerOnsetDelay = 0.0
     channel: GlobalTimerChannel | None = None
@@ -376,9 +386,11 @@ def __repr__(self) -> str:
         return f'{self.__class__.__name__}({values})'
 
 
-class GlobalCounter(BaseModel, validate_assignment=True, title='Global Counter'):
+class GlobalCounter(BaseModel, title='Global Counter'):
     """A global counter in the state machine."""
 
+    model_config = ConfigDict(validate_assignment=True, extra='forbid')
+
     event: Event
     threshold: GlobalCounterThreshold
 
@@ -388,9 +400,11 @@ def __repr__(self) -> str:
         return f'{self.__class__.__name__}({values})'
 
 
-class Condition(BaseModel, validate_assignment=True, title='Condition'):
+class Condition(BaseModel, title='Condition'):
     """A condition in the state machine."""
 
+    model_config = ConfigDict(validate_assignment=True, extra='forbid')
+
     channel: ConditionChannel
     value: ConditionValue
 
@@ -403,6 +417,8 @@ def __repr__(self) -> str:
 class States(ValidatedDict[StateName, State], title='States'):
     """A collection of states."""
 
+    model_config = ConfigDict(json_schema_extra={'additionalProperties': False})
+
     @property
     def transition_targets(self) -> set[str]:
         """A set of all transition targets."""
@@ -422,21 +438,29 @@ def transition_targets(self) -> set[str]:
 class GlobalTimers(ValidatedDict[Index, GlobalTimer], title='Global Timers'):
     """A collection of global timers."""
 
+    model_config = ConfigDict(json_schema_extra={'additionalProperties': False})
+
 
 class GlobalCounters(ValidatedDict[Index, GlobalCounter], title='Global Counters'):
     """A collection of global counters."""
 
+    model_config = ConfigDict(json_schema_extra={'additionalProperties': False})
+
 
 class Conditions(ValidatedDict[Index, Condition], title='Conditions'):
     """A collection of conditions."""
 
+    model_config = ConfigDict(json_schema_extra={'additionalProperties': False})
+
 
-class StateMachine(BaseModel, validate_assignment=True, title='State Machine'):
+class StateMachine(BaseModel, title='State Machine'):
     """Definition of a Bpod finite-state machine."""
 
     model_config = ConfigDict(
+        validate_assignment=True,
+        extra='forbid',
         json_schema_extra={
-            '$id': 'https://github.com/int-brain-lab/bpod-core/blob/main/.schema/statemachine.json',
+            '$id': 'https://raw.githubusercontent.com/int-brain-lab/bpod-core/main/.schema/statemachine.json',
             '$schema': 'https://json-schema.org/draft/2020-12/schema',
         },
     )
diff --git a/docs/source/bpod/index.rst b/docs/source/bpod/index.rst
index 7399f243..6aa950b3 100644
--- a/docs/source/bpod/index.rst
+++ b/docs/source/bpod/index.rst
@@ -181,15 +181,18 @@ current state machine takes to execute.
 Retrieval of Partial Data
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Finally, it is possible to retrieve a partial copy of a state machine's data while it's
-still running. To do so, use the :meth:`~bpod_core.bpod.Bpod.peek_data` method. In the
-following example, we use two state machines per trial. The first measures the duration
-of an input event, while the second one returns an output action of identical duration.
-:meth:`~bpod_core.bpod.Bpod.peek_data` blocks until one of the ``trigger_states`` has
-been reached—in this case the ``pause`` state—and then returns the data collected up to
-that point. This way, you can use the results from one state machine to prepare the next
-without introducing idle time between state machine runs. The final call to
-:meth:`~bpod_core.bpod.Bpod.get_data` will collect data across all trials.
+:meth:`~bpod_core.bpod.Bpod.peek_data` retrieves data from a running state machine
+without waiting for it to finish. It blocks until one of the specified
+``trigger_states`` is reached, then returns a copy of all data collected up to that
+point.
+
+The example below uses two state machines per trial: the first measures the duration of
+an event on ``Port0``; the second plays back an output of that same duration on
+``PWM0``. After starting ``fsm1``, :meth:`~bpod_core.bpod.Bpod.peek_data` blocks until
+the ``pause`` state is reached, extracts the timing, and uses it to configure ``fsm2``
+before queuing it—with no idle time between the two runs. The final
+:meth:`~bpod_core.bpod.Bpod.get_data` call collects data across all trials.
+
 
 .. testcode-code-block:: python3
    :name: peek_data_fsm
@@ -201,11 +204,15 @@ without introducing idle time between state machine runs. The final call to
    from bpod_core.fsm import StateMachine
    from bpod_core.bpod import Bpod
 
-   # construct first state machine
+   # construct first state machine (identical across all trials)
    fsm1 = StateMachine()
-   fsm1.add_state('wait', transitions={'Port1_High': 'measure'})     # wait for 'Port1_High'
-   fsm1.add_state('measure', transitions={'Port1_Low': 'pause'})     # wait for 'Port1_Low'
-   fsm1.add_state('pause', timer=0.5, transitions={'Tup': '>exit'})  # pause, then exit
+   fsm1.add_state('wait', transitions={'Port0_High': 'measure'})
+   fsm1.add_state('measure', transitions={'Port0_Low': 'pause'})
+   fsm1.add_state('pause', timer=0.5, transitions={'Tup': '>exit'})
+
+   # construct second state machine (will be modified within each trial)
+   fsm2 = StateMachine()
+   fsm2.add_state('echo', transitions={'Tup': '>exit'}, actions={'PWM0': 255})
 
    with Bpod() as bpod:
        for i in range(10):
@@ -215,12 +222,17 @@ without introducing idle time between state machine runs. The final call to
            # peek at data once 'pause' state has been reached
            runtime_data = bpod.peek_data(trigger_states=['pause'])
 
-           # calculate duration of 'Port1_High'
-           duration = runtime_data.filter(pl.col("channel") == "Port1")['time'].diff().last()
+           # calculate duration of 'Port0_High'
+           d = runtime_data.filter(pl.col("channel") == "Port0")['time'].diff().last()
 
-           # construct and run second state machine on the fly
-           fsm2 = StateMachine()
-           fsm2.add_state('echo', timer=duration, transitions={'Tup': '>exit'}, actions={'PWM1': 255})
+           # set state timer and run second state machine
+           fsm2.states['echo'].timer = d
            bpod.run(fsm2, trial_number=i)
 
    data = bpod.get_data()  # collect data across all state machine runs
+
+.. note::
+
+   The trial number is normally incremented automatically with each call to
+   :meth:`~bpod_core.bpod.Bpod.run`. Here, two state machines share a single
+   trial, so ``trial_number`` is set explicitly to keep it aligned with the loop index.
diff --git a/docs/source/state_machines/index.rst b/docs/source/state_machines/index.rst
index 8cad87b2..31ca0723 100644
--- a/docs/source/state_machines/index.rst
+++ b/docs/source/state_machines/index.rst
@@ -232,8 +232,8 @@ turning on an output channel:
    :group: hello_world
    :filename: hello_world_04.svg
 
-   fsm.states['Hello'].actions = {'BNC1': 1}
-   fsm.states['World'].actions = {'BNC2': 1}
+   fsm.states['Hello'].actions = {'TTLOut0': 1}
+   fsm.states['World'].actions = {'TTLOut1': 1}
 
 And with that, our `Hello, World!` example is complete:
 
@@ -260,8 +260,8 @@ transitions, and actions) directly in the call to
    from bpod_core.fsm import StateMachine
 
    fsm = StateMachine()
-   fsm.add_state(name='Hello', timer=1.5, transitions={'Tup': 'World'}, actions={'BNC1': 1})
-   fsm.add_state(name='World', timer=1.0, transitions={'Tup': '>exit'}, actions={'BNC2': 1})
+   fsm.add_state(name='Hello', timer=1.5, transitions={'Tup': 'World'}, actions={'TTLOut0': 1})
+   fsm.add_state(name='World', timer=1.0, transitions={'Tup': '>exit'}, actions={'TTLOut1': 1})
 
 .. testcode:: hello_world
    :hide:
diff --git a/pyproject.toml b/pyproject.toml
index 2126eafe..476e3323 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,11 +8,15 @@ version = '0.1.0a12'
 description = "Python package for interfacing with the Bpod finite state machine"
 authors = [{ name = "Florian Rau", email = "bimac@users.noreply.github.com" }]
 classifiers = [
-  "Development Status :: 2 - Pre-Alpha",
+  "Development Status :: 3 - Alpha",
   "Intended Audience :: Science/Research",
-  "License :: OSI Approved :: MIT License",
   "Operating System :: OS Independent",
   "Programming Language :: Python :: 3",
+  "Programming Language :: Python :: 3.10",
+  "Programming Language :: Python :: 3.11",
+  "Programming Language :: Python :: 3.12",
+  "Programming Language :: Python :: 3.13",
+  "Programming Language :: Python :: 3.14",
   "Topic :: Scientific/Engineering",
   "Typing :: Typed",
 ]
@@ -35,7 +39,8 @@ dependencies = [
   "cachetools>=7.0.0",
   "typing_extensions>=4.0",
 ]
-license = { text = "MIT" }
+license = "MIT"
+license-files = ["LICENSE"]
 readme = "README.md"
 requires-python = ">=3.10"