item params: declarative descriptor foundation + 4 pilot items

Adds utils/param_decl.py with Param/ParamSet/kind descriptors. TestItem
declares COMMON_PARAMS (name, doc, condition, key, skipped, …) and a
new _validate_declared_params() method that warns on unknown keys and
errors on missing required ones — opt-in per subclass (skipped while
PARAMS is None to keep the migration incremental).

Migrates sleep, let, msg_dialog, note_dialog as pilots. Behavior is
unchanged for any well-formed .tum; typos like 'timeoot' on a sleep
item now produce a clear WARN listing the accepted parameters.

The descriptor intentionally carries no Python type information —
parameter values that are $(…) / <|…|> expressions only acquire their
effective type after expansion, so a static type would be misleading.
Per-param post-expansion validators stay opt-in via validate=lambda.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/testium/interpreter/test_items/test_item.py

@@ -5,6 +5,9 @@ from copy import deepcopy
 from interpreter.test_items.test_result import TestResult, TestValue
 import api.testium as tm
 from interpreter.utils.params import TestItemParams
+from interpreter.utils.param_decl import (
+    Param, ParamSet, LIST, BLOCK, unknown_keys, missing_required,
+)
 from interpreter.utils.constants import TestItemType as cst_type
 from interpreter.utils.eval import eval_to_boolean, evaluate, post_evaluate
 from runtime.tum_except import ETUMSyntaxError, item_load_context
@@ -13,6 +16,32 @@ LOG_TEST_STOP = '<----- step "{}" finished'
 LOG_TEST_START = '-----> step "{}" started'
 
 
+# Parameters accepted by every test item, regardless of its type. Subclasses
+# concatenate their own ``PARAMS`` to this set; the merged result drives
+# unknown-param warnings and (later) the LSP schema export.
+COMMON_PARAMS = ParamSet(
+    Param("name",            doc="Display name shown in the GUI tree and reports."),
+    Param("doc",             doc="Free-form documentation; surfaced in tooltips."),
+    Param("skipped",         doc="If truthy, the step is skipped (static expression, "
+                                 "evaluated at load time)."),
+    Param("key",             doc="Report key used to classify the result "
+                                 "(typically <test>_PASS or <test>_FAIL)."),
+    Param("stop_on_failure", doc="If true, abort the surrounding container on failure."),
+    Param("execute_on_stop", doc="If true, run this step even when its container "
+                                 "is being stopped (cleanup)."),
+    Param("process_result",  doc="Post-evaluation expression applied to the test result."),
+    Param("store_result",    doc="Global-dict key in which to store the test result."),
+    Param("expected_result", doc="Expected outcome; the step is failed if it doesn't match."),
+    Param("no_fail",         doc="If truthy, never report a FAILURE for this step."),
+    Param("report",          doc="Per-step reporting override."),
+    Param("condition",       doc="Optional gating expression evaluated before each "
+                                 "run; false ⇒ the step is skipped."),
+    Param("steps",  kind=LIST, doc="Children (for container items)."),
+    Param("seq_filename",    doc="(internal) source .tum file of this step; injected "
+                                 "by the loader."),
+)
+
+
 class TestItem:
     pass
 
@@ -97,6 +126,11 @@ def test_data(item: TestItem, child: dict) -> dict:
 
 
 class TestItem:
+    # Subclasses override with their own ParamSet to opt into the declarative
+    # validation. While ``PARAMS`` is empty / unset, the base class skips the
+    # unknown-param check for this item type — keeps the migration incremental.
+    PARAMS = None
+
     def __init__(
         self, dict_item: dict = None, parent: TestItem = None, status_queue=None, filename = ""
     ):
@@ -134,6 +168,13 @@ class TestItem:
             # creation of the params object
             self._prms = TestItemParams(dict_item, parent)
 
+            # Declarative-params validation. Only kicks in when the concrete
+            # subclass declares ``PARAMS`` — items not yet migrated stay
+            # silent. Warnings (not errors) during the migration window so
+            # existing .tum files don't break suddenly; will be flipped to
+            # errors once every item has migrated.
+            self._validate_declared_params(dict_item)
+
             # getting parameters for the test item
             try:
                 self._name = self._prms.getParam("name", default="", processed=True)
@@ -190,6 +231,36 @@ class TestItem:
 
         self.result = TestResult(self, TestValue.FAILURE, "Failure by default")
 
+    def _validate_declared_params(self, dict_item):
+        """Warn on unknown / missing-required params, if PARAMS is declared.
+
+        The check is opt-in per subclass: it only runs when the concrete
+        class sets a non-empty ``PARAMS`` attribute. Items not yet migrated
+        produce no diagnostics — preserving the historical "silently accept
+        anything" behavior until they get their declaration.
+        """
+        if not self.PARAMS:
+            return
+        # ``self._type`` is the parent root type at this point (subclasses set
+        # it after super().__init__), so use the class name as a stable label
+        # in diagnostics. ``self._name`` was preset to the type name by every
+        # subclass before super() ran, which gives a useful prefix.
+        label = f"{type(self).__name__} '{self._name}'"
+        declared = COMMON_PARAMS + self.PARAMS
+        unknown = unknown_keys(declared, dict_item)
+        if unknown:
+            accepted = ", ".join(sorted(declared.names()))
+            for k in unknown:
+                tm.print_warn(
+                    f"{label}: unknown parameter '{k}'. Accepted: {accepted}."
+                )
+        missing = missing_required(declared, dict_item)
+        for k in missing:
+            raise ETUMSyntaxError(
+                f"{label}: required parameter '{k}' is missing.",
+                self._seq_filename,
+            )
+
     def _filter_dict_item(self, dict_item):
         # Stores the content of the step to be displayed
         # in the GUI

src/testium/interpreter/test_items/test_item_let.py

@@ -8,12 +8,20 @@ from interpreter.test_items.test_result import (TestResult, TestValue)
 from runtime.tum_except import ETUMSyntaxError, item_load_context
 import api.testium as tm
 from interpreter.utils.constants import TestItemType as cst
+from interpreter.utils.param_decl import Param, ParamSet, LIST
 
 class TestItemLet(TestItem):
     """let item usage.
     let values: {variable1: a, variable2: /dev/ttyUSB0, variable3: 115200}
     let eval: {conditional_exec: "random.randint(1, 4)"}
     """
+
+    PARAMS = ParamSet(
+        Param("values", kind=LIST, required=True,
+              doc="Mapping (or list of single-pair mappings) of global-dict "
+                  "key → value to set. Values are expanded at execution time."),
+    )
+
     def __init__(self, dict_item, parent = None, status_queue=None, filename=""):
         self._name = cst.TYPE_LET.item_name
         super().__init__(dict_item, parent, status_queue, filename=filename)

src/testium/interpreter/test_items/test_item_msg_dialog.py

@@ -5,6 +5,7 @@ from interpreter.test_items.test_item import test_run
 from interpreter.test_items.test_result import TestValue
 from interpreter.test_items.test_item_dialog_base import TestItemDialogBase, _is_text_mode, _is_interactive
 from interpreter.utils.constants import TestItemType as cst
+from interpreter.utils.param_decl import Param, ParamSet
 from runtime.tum_except import item_load_context
 
 
@@ -12,6 +13,15 @@ class TestItemMsgDialog(TestItemDialogBase):
     """dialog_message item usage.
     dialog_message name: Nice message, question: Open the door and press OK
     """
+
+    PARAMS = ParamSet(
+        Param("question", required=True,
+              doc="Message body shown to the user. Multi-line strings are supported."),
+        Param("auto_result", default=None,
+              doc="Outcome used in batch/non-interactive mode instead of waiting "
+                  "for the user. Truthy ⇒ SUCCESS, None ⇒ FAILURE."),
+    )
+
     def __init__(self, dict_item, parent=None, status_queue=None, filename=""):
         self._name = cst.TYPE_MESSAGE_DLG.item_name
         super().__init__(dict_item, parent, status_queue, filename=filename)

src/testium/interpreter/test_items/test_item_note_dialog.py

@@ -2,11 +2,23 @@ from interpreter.test_items.test_item import test_run
 from interpreter.test_items.test_result import TestValue
 from interpreter.test_items.test_item_dialog_base import TestItemDialogBase, _is_text_mode, _is_interactive
 from interpreter.utils.constants import TestItemType as cst
+from interpreter.utils.param_decl import Param, ParamSet
 from runtime.tum_except import item_load_context
 import api.testium as tm
 
 
 class TestItemNoteDialog(TestItemDialogBase):
+
+    PARAMS = ParamSet(
+        Param("question", required=True,
+              doc="Prompt shown above the note input field."),
+        Param("auto_result", default=None,
+              doc="Batch-mode outcome: None ⇒ FAILURE, 'cancel' ⇒ cancelled, "
+                  "any other truthy ⇒ SUCCESS with auto_value."),
+        Param("auto_value", default=None,
+              doc="Note text used in batch mode when auto_result is set."),
+    )
+
     def __init__(self, dict_item, parent=None, status_queue=None, filename=""):
         self._name = cst.TYPE_NOTE_DLG.item_name
         super().__init__(dict_item, parent, status_queue, filename=filename)

src/testium/interpreter/test_items/test_item_sleep.py

@@ -7,6 +7,7 @@ import api.testium as tm
 from interpreter.test_items.test_item import (TestItem, test_run)
 from interpreter.test_items.test_result import (TestValue)
 from interpreter.utils.constants import TestItemType as cst
+from interpreter.utils.param_decl import Param, ParamSet
 from runtime.tum_except import ETUMSyntaxError, ETUMRuntimeError, item_load_context
 
 class TestItemSleep(TestItem):
@@ -14,6 +15,15 @@ class TestItemSleep(TestItem):
     sleep timeout: 10
     """
 
+    PARAMS = ParamSet(
+        Param("timeout", required=True,
+              doc="Duration to sleep. Number of seconds, or a string "
+                  "like '1d 2h 30m 15s'."),
+        Param("dialog", default=False,
+              doc="If true, show a cancel dialog (GUI mode) or an interactive "
+                  "Ctrl+C-able countdown (text mode)."),
+    )
+
     def __init__(self, dict_item, parent = None, status_queue=None, filename=""):
         self._name = cst.TYPE_SLEEP.item_name
         super().__init__(dict_item, parent, status_queue, filename=filename)

src/testium/interpreter/utils/param_decl.py

@@ -0,0 +1,175 @@
+"""Declarative description of a test item's accepted parameters.
+
+Each ``TestItem`` subclass declares its parameter surface as a class
+attribute::
+
+    class TestItemFoo(TestItem):
+        PARAMS = ParamSet(
+            Param("bar",      required=True,  doc="The bar value."),
+            Param("baz",      default=0,      doc="Optional baz."),
+            Param("modes",    kind=LIST,      doc="Iterable of modes."),
+            Param("strategy", kind=ENUM("a", "b"), doc="..."),
+            Param("opts",     kind=BLOCK,     doc="Sub-block."),
+        )
+
+The base ``TestItem.__init__`` consumes both ``COMMON_PARAMS`` (defined
+in ``test_item.py``) and the subclass ``PARAMS`` to:
+
+* warn on any key in the user's YAML that isn't declared anywhere
+  (catches typos like ``param_filee``);
+* expose a machine-readable schema for documentation generation and,
+  eventually, an LSP server.
+
+The descriptor is **purely about shape and naming**. Type coercion and
+runtime checking of expanded values remain the responsibility of each
+item's ``execute()`` method — most parameters are expressions
+(``$(...)`` / ``<| ... |>``) whose effective type is only known after
+expansion, so a static type would be misleading.
+
+Validation of *values* (e.g. ``start_time`` must match HH:MM) can be
+attached per-param via ``validate=lambda v: ...`` and is applied at
+execution time on the expanded value, not at load time.
+"""
+
+from dataclasses import dataclass, field
+from typing import Any, Callable, Optional, Union
+
+
+# ---------- Parameter "kinds" -------------------------------------------------
+#
+# These describe the YAML *shape* expected for a parameter, not its
+# semantic type. They drive the LSP completion (do we suggest a single
+# value, a list, a sub-block, an enum picker?) and the unknown-param
+# diagnostic; nothing more.
+
+SCALAR = "scalar"  # single value (string, number, bool, expression, ...)
+LIST = "list"      # YAML list — the historical ``getParamAll`` case
+BLOCK = "block"    # nested dict — e.g. ``cycle.exit:``
+
+
+@dataclass(frozen=True)
+class Enum:
+    """Closed enumeration of acceptable scalar values."""
+    values: tuple
+
+    def __init__(self, *values):
+        # frozen=True forbids assignment; bypass via object.__setattr__.
+        object.__setattr__(self, "values", tuple(values))
+
+    def __repr__(self):
+        return f"Enum({', '.join(repr(v) for v in self.values)})"
+
+
+Kind = Union[str, Enum]
+
+
+# ---------- The descriptor ----------------------------------------------------
+
+_MISSING = object()
+
+
+@dataclass(frozen=True)
+class Param:
+    """Declarative description of one accepted parameter.
+
+    Attributes
+    ----------
+    name : str
+        The YAML key.
+    kind : ``SCALAR`` (default) | ``LIST`` | ``BLOCK`` | ``Enum(...)``
+        The YAML shape expected.
+    required : bool
+        If True, missing the parameter is a load-time error.
+    default : Any
+        Default value when the parameter is absent. ``_MISSING`` when no
+        default was set (used to distinguish "absent" from "None").
+    doc : str
+        Free-form description used for hover / generated documentation.
+    validate : Optional[Callable[[Any], bool]]
+        Optional post-expansion validator, evaluated at ``execute()``
+        time on the effective (expanded) value. Returning ``False``
+        raises a clear error pointing at the param.
+    """
+    name: str
+    kind: Kind = SCALAR
+    required: bool = False
+    default: Any = _MISSING
+    doc: str = ""
+    validate: Optional[Callable[[Any], bool]] = None
+
+    def has_default(self):
+        return self.default is not _MISSING
+
+    def to_schema(self):
+        """Return a dict suitable for JSON Schema generation."""
+        s = {"name": self.name, "required": self.required, "doc": self.doc}
+        if isinstance(self.kind, Enum):
+            s["kind"] = "enum"
+            s["enum"] = list(self.kind.values)
+        else:
+            s["kind"] = self.kind
+        if self.has_default():
+            s["default"] = self.default
+        return s
+
+
+class ParamSet:
+    """Ordered, name-indexed collection of ``Param`` descriptors.
+
+    Supports concatenation (``COMMON_PARAMS + SUBCLASS_PARAMS``) to
+    merge the common surface with each item's own params. Later
+    declarations override earlier ones (so a subclass can tighten a
+    common param's docstring without redeclaring everything).
+    """
+
+    def __init__(self, *params):
+        self._params = {}
+        for p in params:
+            self.add(p)
+
+    def add(self, param):
+        if not isinstance(param, Param):
+            raise TypeError(f"ParamSet only accepts Param instances, got {type(param).__name__}")
+        self._params[param.name] = param
+
+    def __iter__(self):
+        return iter(self._params.values())
+
+    def __contains__(self, name):
+        return name in self._params
+
+    def __getitem__(self, name):
+        return self._params[name]
+
+    def names(self):
+        return tuple(self._params.keys())
+
+    def __add__(self, other):
+        if not isinstance(other, ParamSet):
+            return NotImplemented
+        merged = ParamSet()
+        merged._params = {**self._params, **other._params}
+        return merged
+
+    def to_schema(self):
+        return [p.to_schema() for p in self._params.values()]
+
+
+# ---------- Validation primitives --------------------------------------------
+
+def unknown_keys(declared, user_dict):
+    """Return the user-provided keys that are not declared in *declared*.
+
+    *declared* is a ``ParamSet``; *user_dict* is the raw YAML mapping
+    for the item. Unknown keys catch typos and obsolete parameters.
+    """
+    if not isinstance(user_dict, dict):
+        return ()
+    return tuple(k for k in user_dict.keys() if k not in declared)
+
+
+def missing_required(declared, user_dict):
+    """Return the names of declared required params absent from *user_dict*."""
+    if not isinstance(user_dict, dict):
+        return tuple(p.name for p in declared if p.required)
+    return tuple(p.name for p in declared if p.required and p.name not in user_dict)