diff --git a/tests/test_tool_date_enforcement.py b/tests/test_tool_date_enforcement.py
index 55355823d..8beb479d3 100644
--- a/tests/test_tool_date_enforcement.py
+++ b/tests/test_tool_date_enforcement.py
@@ -141,6 +141,14 @@ def test_an_unpadded_date_reaches_the_vendor_in_canonical_form():
     assert args[-2:] == ("2026-07-01", "2026-07-03")
 
 
+@pytest.mark.unit
+@pytest.mark.parametrize("tool", [tools.get_balance_sheet, tools.get_cashflow, tools.get_income_statement])
+def test_a_statement_frequency_is_one_the_vendors_serve(tool):
+    # Any other word was served annual figures under the word asked for.
+    schema = tool.tool_call_schema.model_json_schema()["properties"]["freq"]
+    assert schema["enum"] == ["annual", "quarterly"]
+
+
 @pytest.mark.unit
 def test_direct_call_without_state_is_unchanged():
     with mock.patch.object(tools, "route_to_vendor", return_value="ok") as routed:
diff --git a/tradingagents/agents/tools.py b/tradingagents/agents/tools.py
index c0e9adf74..e2a7eb362 100644
--- a/tradingagents/agents/tools.py
+++ b/tradingagents/agents/tools.py
@@ -4,7 +4,7 @@ Each dated tool takes the run's ``trade_date`` from graph state (``InjectedState
 and never serves data past it, whatever date the model asks for.
 """
 
-from typing import Annotated
+from typing import Annotated, Literal
 
 from langchain_core.tools import tool
 from langgraph.prebuilt import InjectedState
@@ -114,7 +114,7 @@ def get_fundamentals(
 @tool
 def get_balance_sheet(
     ticker: Annotated[str, InjectedState("company_of_interest")],
-    freq: Annotated[str, "reporting frequency: annual/quarterly"] = "quarterly",
+    freq: Annotated[Literal["annual", "quarterly"], "reporting frequency"] = "quarterly",
     curr_date: Annotated[str, "current date you are trading at, yyyy-mm-dd"] = None,
     trade_date: Annotated[str, InjectedState("trade_date")] = "",
 ) -> str:
@@ -133,7 +133,7 @@ def get_balance_sheet(
 @tool
 def get_cashflow(
     ticker: Annotated[str, InjectedState("company_of_interest")],
-    freq: Annotated[str, "reporting frequency: annual/quarterly"] = "quarterly",
+    freq: Annotated[Literal["annual", "quarterly"], "reporting frequency"] = "quarterly",
     curr_date: Annotated[str, "current date you are trading at, yyyy-mm-dd"] = None,
     trade_date: Annotated[str, InjectedState("trade_date")] = "",
 ) -> str:
@@ -152,7 +152,7 @@ def get_cashflow(
 @tool
 def get_income_statement(
     ticker: Annotated[str, InjectedState("company_of_interest")],
-    freq: Annotated[str, "reporting frequency: annual/quarterly"] = "quarterly",
+    freq: Annotated[Literal["annual", "quarterly"], "reporting frequency"] = "quarterly",
     curr_date: Annotated[str, "current date you are trading at, yyyy-mm-dd"] = None,
     trade_date: Annotated[str, InjectedState("trade_date")] = "",
 ) -> str: