diff --git a/lute/io/models/tests.py b/lute/io/models/tests.py
index 1958e663..adf0faf4 100644
--- a/lute/io/models/tests.py
+++ b/lute/io/models/tests.py
@@ -27,7 +27,7 @@
 ]
 __author__ = "Gabriel Dorlhiac"
 
-from typing import Dict, Any
+from typing import Dict, Any, Optional
 
 from pydantic import (
     BaseModel,
@@ -42,32 +42,47 @@
 class TestParameters(TaskParameters):
     """Parameters for the test Task `Test`."""
 
-    float_var: float = 0.01
-    str_var: str = "test"
+    float_var: float = Field(0.01, description="A floating point number.")
+    str_var: str = Field("test", description="A string.")
 
     class CompoundVar(BaseModel):
         int_var: int = 1
         dict_var: Dict[str, str] = {"a": "b"}
 
-    compound_var: CompoundVar
-    throw_error: bool = False
+    compound_var: CompoundVar = Field(
+        description=(
+            "A compound parameter - consists of a `int_var` (int) and `dict_var`"
+            " (Dict[str, str])."
+        )
+    )
+    throw_error: bool = Field(
+        False, description="If `True`, raise an exception to test error handling."
+    )
 
 
 class TestBinaryParameters(ThirdPartyParameters):
-    executable: str = "/sdf/home/d/dorlhiac/test_tasks/test_threads"
-    p_arg1: int = 1
+    executable: str = Field(
+        "/sdf/home/d/dorlhiac/test_tasks/test_threads",
+        description="Multi-threaded test binary.",
+    )
+    p_arg1: int = Field(1, descriptions="Number of threads.")
 
 
 class TestBinaryErrParameters(ThirdPartyParameters):
     """Same as TestBinary, but exits with non-zero code."""
 
-    executable: str = "/sdf/home/d/dorlhiac/test_tasks/test_threads_err"
-    p_arg1: int = 1
+    executable: str = Field(
+        "/sdf/home/d/dorlhiac/test_tasks/test_threads_err",
+        description="Multi-threaded tes tbinary with non-zero exit code.",
+    )
+    p_arg1: int = Field(1, description="Number of threads.")
 
 
 class TestSocketParameters(TaskParameters):
-    array_size: int = 10000
-    num_arrays: int = 10
+    array_size: int = Field(
+        10000, description="Size of an array to send (number of values) via socket."
+    )
+    num_arrays: int = Field(10, description="Number of arrays to send via socket.")
 
 
 class TestWriteOutputParameters(TaskParameters):
@@ -83,8 +98,9 @@ class TestReadOutputParameters(TaskParameters):
     @validator("in_file", always=True)
     def validate_in_file(cls, in_file: str, values: Dict[str, Any]) -> str:
         if in_file == "":
-            filename: str = read_latest_db_entry(
+            filename: Optional[str] = read_latest_db_entry(
                 f"{values['lute_config'].work_dir}", "TestWriteOutput", "outfile_name"
             )
-            in_file: str = f"{values['lute_config'].work_dir}/{filename}"
+            if filename is not None:
+                return f"{values['lute_config'].work_dir}/{filename}"
         return in_file