Add test for Literal in describe_model (#101)

* test: check Literal handling in describe_model

* Show Literal values in model description

* Document Literal support

Author: simba-git

README.md

@@ -90,6 +90,7 @@ AI agents can now:
 Wrap your existing APIs with semantic understanding:
 
 ```python
+from typing import Literal
 from enrichmcp import EnrichMCP, EnrichModel, Relationship
 from pydantic import Field
 
@@ -101,7 +102,9 @@ class Customer(EnrichModel):
 
     id: int = Field(description="Unique customer ID")
     email: str = Field(description="Primary contact email")
-    tier: str = Field(description="Subscription tier: free, pro, enterprise")
+    tier: Literal["free", "pro", "enterprise"] = Field(
+        description="Subscription tier"
+    )
 
     # Define navigable relationships
     orders: list["Order"] = Relationship(description="Customer's purchase history")
@@ -113,7 +116,9 @@ class Order(EnrichModel):
     id: int = Field(description="Order ID")
     customer_id: int = Field(description="Associated customer")
     total: float = Field(description="Order total in USD")
-    status: str = Field(description="Order status: pending, shipped, delivered")
+    status: Literal["pending", "shipped", "delivered"] = Field(
+        description="Order status"
+    )
 
     customer: Customer = Relationship(description="Customer who placed this order")
 
@@ -242,6 +247,7 @@ class Order(EnrichModel):
     email: EmailStr = Field(description="Customer email")
     status: Literal["pending", "shipped", "delivered"]
 ```
+`describe_model()` will list these allowed values so agents know the valid options.
 
 ### ✏️ Mutability & CRUD
 

docs/api/app.md

@@ -117,6 +117,7 @@ Generate a comprehensive description of the data model. This is used internally
 
 **Returns:**
 A formatted string containing all entities, fields, and relationships.
+If a field is annotated with `typing.Literal`, the allowed values are shown in the output.
 
 ## Built-in Resources
 

docs/concepts.md

@@ -245,6 +245,7 @@ async def create_customer(
     # All inputs are validated before reaching your code
     ...
 ```
+The `describe_model()` output will list these allowed values.
 
 ## Context and Lifespan Management
 

src/enrichmcp/app.py

@@ -8,9 +8,12 @@
 from collections.abc import Callable
 from typing import (
     Any,
+    Literal,
     Protocol,
     TypeVar,
     cast,
+    get_args,
+    get_origin,
     runtime_checkable,
 )
 
@@ -259,9 +262,14 @@ def describe_model(self) -> str:
                 # Get field type and description
                 field_type = "Any"  # Default type if annotation is None
                 if field.annotation is not None:
-                    field_type = str(field.annotation)  # Always safe fallback
-                    if hasattr(field.annotation, "__name__"):
-                        field_type = field.annotation.__name__
+                    annotation = field.annotation
+                    if get_origin(annotation) is Literal:
+                        values = ", ".join(repr(v) for v in get_args(annotation))
+                        field_type = f"Literal[{values}]"
+                    else:
+                        field_type = str(annotation)  # Always safe fallback
+                        if hasattr(annotation, "__name__"):
+                            field_type = annotation.__name__
                 field_desc = field.description
                 extra = getattr(field, "json_schema_extra", None)
                 if extra is None:

src/enrichmcp/entity.py

@@ -5,7 +5,7 @@
 """
 
 from collections.abc import Callable
-from typing import Any, Literal, cast
+from typing import Any, Literal, cast, get_args, get_origin
 
 from pydantic import BaseModel, ConfigDict
 from pydantic.main import IncEx
@@ -107,9 +107,14 @@ def describe(self) -> str:
             # Get field type and description
             field_type = "Any"  # Default type if annotation is None
             if field.annotation is not None:
-                field_type = str(field.annotation)  # Always safe fallback
-                if hasattr(field.annotation, "__name__"):
-                    field_type = field.annotation.__name__
+                annotation = field.annotation
+                if get_origin(annotation) is Literal:
+                    values = ", ".join(repr(v) for v in get_args(annotation))
+                    field_type = f"Literal[{values}]"
+                else:
+                    field_type = str(annotation)  # Always safe fallback
+                    if hasattr(annotation, "__name__"):
+                        field_type = annotation.__name__
             field_desc = field.description
 
             extra = getattr(field, "json_schema_extra", None)

tests/test_model_description.py

@@ -1,4 +1,4 @@
-from typing import Any
+from typing import Any, Literal
 
 from pydantic import Field
 
@@ -132,3 +132,17 @@ class Article(EnrichModel):
     assert "**categories**" in description and "Article categories" in description
 
     assert "- **author** → Relationship: Article author" in description
+
+
+def test_describe_model_with_literal_type():
+    """Test describe_model with Literal field types."""
+    app = EnrichMCP("Enum API", description="A model with Literal fields")
+
+    @app.entity(description="Entity using Literal")
+    class Item(EnrichModel):
+        status: Literal["pending", "complete"] = Field(description="Item status")
+
+    description = app.describe_model()
+
+    assert "## Item" in description
+    assert "- **status** (Literal['pending', 'complete']): Item status" in description