diff --git a/src/basic_memory/mcp/tools/edit_note.py b/src/basic_memory/mcp/tools/edit_note.py
index 79122a6a3..f45fa79c7 100644
--- a/src/basic_memory/mcp/tools/edit_note.py
+++ b/src/basic_memory/mcp/tools/edit_note.py
@@ -1,6 +1,6 @@
 """Edit note tool for Basic Memory MCP server."""
 
-from typing import TYPE_CHECKING, Annotated, Optional, Literal
+from typing import TYPE_CHECKING, Annotated, Literal, Optional
 
 import logfire
 from httpx import HTTPStatusError
@@ -31,6 +31,15 @@
 )
 from basic_memory.utils import normalize_project_reference, validate_project_path
 
+EDIT_OPERATIONS = (
+    "append",
+    "prepend",
+    "find_replace",
+    "replace_section",
+    "insert_before_section",
+    "insert_after_section",
+)
+
 
 def _parse_identifier_to_title_and_directory(identifier: str) -> tuple[str, str]:
     """Parse an identifier into (title, directory) for creating a new note.
@@ -318,7 +327,7 @@ def _format_error_response(
 )
 async def edit_note(
     identifier: str,
-    operation: str,
+    operation: Annotated[str, Field(json_schema_extra={"enum": list(EDIT_OPERATIONS)})],
     # Accept common replacement-content aliases. Models trained on diff/patch
     # APIs reach for new_content/replacement/replace_with on first try.
     content: Annotated[
@@ -512,17 +521,9 @@ async def edit_note(
             )
 
             # Validate operation
-            valid_operations = [
-                "append",
-                "prepend",
-                "find_replace",
-                "replace_section",
-                "insert_before_section",
-                "insert_after_section",
-            ]
-            if operation not in valid_operations:
+            if operation not in EDIT_OPERATIONS:
                 raise ValueError(
-                    f"Invalid operation '{operation}'. Must be one of: {', '.join(valid_operations)}"
+                    f"Invalid operation '{operation}'. Must be one of: {', '.join(EDIT_OPERATIONS)}"
                 )
 
             # Validate required parameters for specific operations
diff --git a/tests/mcp/test_tool_contracts.py b/tests/mcp/test_tool_contracts.py
index bd4cc9f98..8c4d71e72 100644
--- a/tests/mcp/test_tool_contracts.py
+++ b/tests/mcp/test_tool_contracts.py
@@ -165,6 +165,15 @@
     "search_notes_ui": {"readOnlyHint": True, "destructiveHint": False},
 }
 
+EXPECTED_EDIT_NOTE_OPERATIONS = [
+    "append",
+    "prepend",
+    "find_replace",
+    "replace_section",
+    "insert_before_section",
+    "insert_after_section",
+]
+
 
 TOOL_FUNCTIONS: dict[str, object] = {
     "build_context": tools.build_context,
@@ -250,6 +259,19 @@ async def test_mcp_tool_annotations_meet_directory_requirements():
         )
 
 
+@pytest.mark.asyncio
+async def test_edit_note_operation_schema_exposes_supported_operations():
+    """The edit operation is a fixed choice set, not a free-form string."""
+    tool_list = await mcp.list_tools()
+    edit_note_tool = next(tool for tool in tool_list if tool.name == "edit_note")
+
+    input_schema = edit_note_tool.to_mcp_tool().inputSchema
+    operation_schema = input_schema["properties"]["operation"]
+
+    assert operation_schema["type"] == "string"
+    assert operation_schema["enum"] == EXPECTED_EDIT_NOTE_OPERATIONS
+
+
 @pytest.mark.asyncio
 async def test_mcp_tools_have_title_and_tags():
     """Every registered MCP tool must declare a human-readable title and at least one tag.