From 25b927f0f00f0839f2e9ca044fd9cf0c0cf00084 Mon Sep 17 00:00:00 2001
From: Anas Khan <83116240+anxkhn@users.noreply.github.com>
Date: Sun, 5 Jul 2026 12:09:11 +0530
Subject: [PATCH] fix(utils): emit multi-type tool params as JSON array

convert_function_to_tool serialized a parameter with a union type (e.g.
Union[int, str]) as the comma-joined string "integer, string" instead of the
JSON-Schema array ["integer", "string"]. The server's PropertyType.UnmarshalJSON
reads that as a single, invalid type name, so the parameter's type constraint is
silently dropped. Because types is a set, the joined string order also varied
between runs.

Emit a single type as a bare string (unchanged) and multiple types as a sorted
list, which matches Tool.Function.Parameters.Property.type (Union[str,
Sequence[str]]) and the array form the server expects. Sorting removes the
non-determinism. Update test_function_with_all_types to assert the multi-type
property is the array ['integer', 'string'] rather than parsing a string.

Signed-off-by: Anas Khan <83116240+anxkhn@users.noreply.github.com>
---
 ollama/_utils.py    | 7 ++++++-
 tests/test_utils.py | 6 ++++--
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/ollama/_utils.py b/ollama/_utils.py
index 15f1cc0c..ce2aace1 100644
--- a/ollama/_utils.py
+++ b/ollama/_utils.py
@@ -73,9 +73,14 @@ def convert_function_to_tool(func: Callable) -> Tool:
       schema['required'].remove(k)
       types.discard('null')
 
+    # Emit a single type as a string and multiple types as a JSON-Schema array.
+    # A comma-joined string (e.g. 'integer, string') is parsed by the server as one
+    # invalid type name, silently dropping the constraint. Sorting also makes the
+    # output deterministic across runs since types is a set.
+    sorted_types = sorted(types)
     schema['properties'][k] = {
       'description': parsed_docstring[k],
-      'type': ', '.join(types),
+      'type': sorted_types if len(sorted_types) > 1 else ''.join(sorted_types),
     }
 
   tool = Tool(
diff --git a/tests/test_utils.py b/tests/test_utils.py
index cb9e0d4f..1c99ee0a 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -98,8 +98,10 @@ def all_types(
   if sys.version_info >= (3, 10):
     assert tool['function']['parameters']['properties']['z']['type'] == 'array'
     assert tool['function']['parameters']['properties']['w']['type'] == 'object'
-    assert {x.strip().strip("'") for x in tool['function']['parameters']['properties']['v']['type'].removeprefix('[').removesuffix(']').split(',')} == {'string', 'integer'}
-    assert tool['function']['parameters']['properties']['v']['type'] != 'null'
+    # A multi-type parameter must be a JSON array, not a comma-joined string, so the
+    # server parses each type instead of one invalid 'integer, string' type name.
+    assert isinstance(tool['function']['parameters']['properties']['v']['type'], list)
+    assert tool['function']['parameters']['properties']['v']['type'] == ['integer', 'string']
     assert tool['function']['parameters']['required'] == ['x', 'y', 'z', 'w']
   else:
     assert tool['function']['parameters']['properties']['z']['type'] == 'array'