SEP-1330: Elicitation Enum Schema Improvements and Standards Compliance (#1246)

Co-authored-by: Tapan Chugh <tapanc@cs.washington.edu>
Co-authored-by: Felix Weinberger <fweinberger@anthropic.com>
Co-authored-by: Felix Weinberger <3823880+felixweinberger@users.noreply.github.com>

examples/servers/everything-server/mcp_everything_server/server.py

@@ -198,6 +198,65 @@ async def test_elicitation_sep1034_defaults(ctx: Context[ServerSession, None]) -
         return f"Elicitation not supported or error: {str(e)}"
 
 
+class EnumSchemasTestSchema(BaseModel):
+    """Schema for testing enum schema variations (SEP-1330)"""
+
+    untitledSingle: str = Field(
+        description="Simple enum without titles", json_schema_extra={"enum": ["active", "inactive", "pending"]}
+    )
+    titledSingle: str = Field(
+        description="Enum with titled options (oneOf)",
+        json_schema_extra={
+            "oneOf": [
+                {"const": "low", "title": "Low Priority"},
+                {"const": "medium", "title": "Medium Priority"},
+                {"const": "high", "title": "High Priority"},
+            ]
+        },
+    )
+    untitledMulti: list[str] = Field(
+        description="Multi-select without titles",
+        json_schema_extra={"items": {"type": "string", "enum": ["read", "write", "execute"]}},
+    )
+    titledMulti: list[str] = Field(
+        description="Multi-select with titled options",
+        json_schema_extra={
+            "items": {
+                "anyOf": [
+                    {"const": "feature", "title": "New Feature"},
+                    {"const": "bug", "title": "Bug Fix"},
+                    {"const": "docs", "title": "Documentation"},
+                ]
+            }
+        },
+    )
+    legacyEnum: str = Field(
+        description="Legacy enum with enumNames",
+        json_schema_extra={
+            "enum": ["small", "medium", "large"],
+            "enumNames": ["Small Size", "Medium Size", "Large Size"],
+        },
+    )
+
+
+@mcp.tool()
+async def test_elicitation_sep1330_enums(ctx: Context[ServerSession, None]) -> str:
+    """Tests elicitation with enum schema variations per SEP-1330"""
+    try:
+        result = await ctx.elicit(
+            message="Please select values using different enum schema types", schema=EnumSchemasTestSchema
+        )
+
+        if result.action == "accept":
+            content = result.data.model_dump_json()
+        else:
+            content = "{}"
+
+        return f"Elicitation completed: action={result.action}, content={content}"
+    except Exception as e:
+        return f"Elicitation not supported or error: {str(e)}"
+
+
 @mcp.tool()
 def test_error_handling() -> str:
     """Tests error response handling"""