Fix MCP tools not working with ChatGoogle

CHANGELOG.md

@@ -36,6 +36,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Fixed structured data extraction with `ChatAnthropic()` failing for Pydantic models containing nested types (e.g., `list[NestedModel]`). The issue was that `$defs` (containing nested type definitions) was incorrectly placed inside the schema, breaking JSON `$ref` pointer references. (#100)
 * Fixed MCP tools failing with OpenAI providers due to strict mode schema validation. OpenAI's strict mode rejects standard JSON Schema features like `format: "uri"` and requires all properties in the `required` array. MCP tools now set `strict=false` to use standard JSON Schema conventions. (#255)
+* Fixed MCP tools not working with `ChatGoogle()`. (#257)
 * Tool functions parameters that are `typing.Annotated` with a `pydantic.Field` (e.g., `def add(x: Annotated[int, Field(description="First number")])`) are now handled correctly. (#251)
 
 ## [0.14.0] - 2025-12-09

chatlas/_provider_google.py

@@ -299,6 +299,7 @@ def _chat_perform_args(
         from google.genai.types import (
             FunctionDeclaration,
             GenerateContentConfig,
+            Schema,
             ToolListUnion,
         )
         from google.genai.types import Tool as GoogleTool
@@ -336,11 +337,18 @@ def _chat_perform_args(
                     gtool = GoogleTool.model_validate(tool.definition)
                     google_tools.append(gtool)
                 else:
+                    func = tool.schema["function"]
+                    params = func.get("parameters")
                     gtool = GoogleTool(
                         function_declarations=[
-                            FunctionDeclaration.from_callable(
-                                client=self._client._api_client,
-                                callable=tool.func,
+                            FunctionDeclaration(
+                                name=func["name"],
+                                description=func.get("description"),
+                                parameters=Schema.model_validate(
+                                    _strip_additional_properties(params)
+                                )
+                                if params
+                                else None,
                             )
                         ]
                     )
@@ -726,3 +734,24 @@ def ChatVertex(
         ),
         system_prompt=system_prompt,
     )
+
+
+def _strip_additional_properties(params: dict[str, Any]) -> dict[str, Any]:
+    """
+    Recursively remove additionalProperties from JSON schema.
+
+    Google's API doesn't accept additionalProperties in tool schemas,
+    so we strip it before passing to Schema.model_validate().
+    """
+    result = {k: v for k, v in params.items() if k != "additionalProperties"}
+
+    if "properties" in result and isinstance(result["properties"], dict):
+        result["properties"] = {
+            k: _strip_additional_properties(v) if isinstance(v, dict) else v
+            for k, v in result["properties"].items()
+        }
+
+    if "items" in result and isinstance(result["items"], dict):
+        result["items"] = _strip_additional_properties(result["items"])
+
+    return result

tests/_vcr/test_provider_google/test_tools_parallel.yaml

@@ -21,20 +21,20 @@ interactions:
       Host:
       - generativelanguage.googleapis.com
       x-goog-api-client:
-      - google-genai-sdk/1.56.0 gl-python/3.11.13
+      - google-genai-sdk/1.56.0 gl-python/3.12.11
     method: POST
     uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:streamGenerateContent?alt=sse
   response:
     body:
       string: "data: {\"candidates\": [{\"content\": {\"parts\": [{\"functionCall\":
         {\"name\": \"favorite_color\",\"args\": {\"_person\": \"Joe\"}},\"thoughtSignature\":
-        \"CiQBcsjafEcxf/2DYJh2KLN0ZyvZXL8qb4eVwpfO1vMCbc+FiI4KdQFyyNp83WPKtw1VCcGDQEHMo5P3ZwwuQVnRgXLHuVpY6pIuISKWq2ahOuhS+R5bmNhTgWLnQZVizSzuoHQvYB+UKBpzHivSACk+/3ev+DdTh/yX3bDryuehMGmfRobrHcHgF14KX9WuMstDN2U8jDu667vWxwrLAQFyyNp8DHJkkPOE6BNUMI5kKtPnOrgc2WbCgjNj4NtwnieDVCXEWRhs8UvvI4bs6T20AHzhyvbVM/iZVcJ3pOWUxTy4vQlrVWQXXpkhMPdHUGNheP3AGhdqQWa7vF8AeR48TUhztTYntyMOwI4ZIkB0C5iqukbIOjGFwM820OpQoy/jfIgGpN0lWzEAek4i/mRiU2xyks5hnaq8OZ1Hb81rIPMFMrkhNp+ubM5H1ba6vpRv7TH3Lt53HsNJDLIqqvFvLxq+JtnjUGLT\"},{\"functionCall\":
+        \"CiQBcsjafMjxiJn3cWg1h7gi5wrPZplGeMGBGKbMKSrgBmOQ3ToKdQFyyNp8iRQFDsoj4U/xFCCuVdfsNoSR6oJhg9BkrMdgX3fMpRFugrAETa9LVnXWl/Nquk9tpc0s36K4w4enJeGRlWHXCj2xA0irMk3076hl1+cVvPB+AXzl1v+wkkCEKx2DmnmQWqMlEdCri/yhx4fbZB5PiQrLAQFyyNp883zKACGlUvM4xF23wAAyCGnBSfNIKbUa0KjfsoiPDhObJdVrtY1f2Y/eQsOx+Cwgg/Iwr4LyC+JpjYn/bhHDkgVQqHOKB8gpt9CSKQ9d5INULjjX7Ugx3wgg40sJXHDelBzi28F1UN+Fx5aVh7TTd1cMnoFqW7Hxsy4+7N+nabYJZY2pWO+z7WKv7p3YvETy7XdXm3FpNs3VUrBArs1oD+g+2fxOWR47loS9VOpVto5ChqbwSBCqks3B0SyhGuVBZp9E7Rqy\"},{\"functionCall\":
         {\"name\": \"favorite_color\",\"args\": {\"_person\": \"Hadley\"}}}],\"role\":
         \"model\"},\"finishReason\": \"STOP\",\"index\": 0,\"finishMessage\": \"Model
         generated function call(s).\"}],\"usageMetadata\": {\"promptTokenCount\":
         80,\"candidatesTokenCount\": 31,\"totalTokenCount\": 170,\"promptTokensDetails\":
         [{\"modality\": \"TEXT\",\"tokenCount\": 80}],\"thoughtsTokenCount\": 59},\"modelVersion\":
-        \"gemini-2.5-flash\",\"responseId\": \"cLBVabe2A8vO_uMP5cWO6As\"}\r\n\r\n"
+        \"gemini-2.5-flash\",\"responseId\": \"_nBYaYTfOKOi_uMPi9GGwQ8\"}\r\n\r\n"
     headers:
       Alt-Svc:
       - h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
@@ -43,11 +43,11 @@ interactions:
       Content-Type:
       - text/event-stream
       Date:
-      - Wed, 31 Dec 2025 23:23:28 GMT
+      - Sat, 03 Jan 2026 01:29:35 GMT
       Server:
       - scaffolding on HTTPServer2
       Server-Timing:
-      - gfet4t7; dur=692
+      - gfet4t7; dur=676
       Transfer-Encoding:
       - chunked
       Vary:
@@ -90,17 +90,17 @@ interactions:
       Host:
       - generativelanguage.googleapis.com
       x-goog-api-client:
-      - google-genai-sdk/1.56.0 gl-python/3.11.13
+      - google-genai-sdk/1.56.0 gl-python/3.12.11
     method: POST
     uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:streamGenerateContent?alt=sse
   response:
     body:
       string: "data: {\"candidates\": [{\"content\": {\"parts\": [{\"text\": \"Joe:
-        sage green, Hadley: red\",\"thoughtSignature\": \"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\"}],\"role\":
+        sage green, Hadley: red\",\"thoughtSignature\": \"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\"}],\"role\":
         \"model\"},\"finishReason\": \"STOP\",\"index\": 0}],\"usageMetadata\": {\"promptTokenCount\":
         140,\"candidatesTokenCount\": 8,\"totalTokenCount\": 254,\"promptTokensDetails\":
         [{\"modality\": \"TEXT\",\"tokenCount\": 140}],\"thoughtsTokenCount\": 106},\"modelVersion\":
-        \"gemini-2.5-flash\",\"responseId\": \"cbBVafhco-H-4w_Uvp2JDA\"}\r\n\r\n"
+        \"gemini-2.5-flash\",\"responseId\": \"_3BYae7dONql_uMPt9e6qAw\"}\r\n\r\n"
     headers:
       Alt-Svc:
       - h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
@@ -109,11 +109,11 @@ interactions:
       Content-Type:
       - text/event-stream
       Date:
-      - Wed, 31 Dec 2025 23:23:29 GMT
+      - Sat, 03 Jan 2026 01:29:36 GMT
       Server:
       - scaffolding on HTTPServer2
       Server-Timing:
-      - gfet4t7; dur=806
+      - gfet4t7; dur=813
       Transfer-Encoding:
       - chunked
       Vary:

tests/_vcr/test_provider_google/test_tools_sequential.yaml

@@ -25,19 +25,19 @@ interactions:
       Host:
       - generativelanguage.googleapis.com
       x-goog-api-client:
-      - google-genai-sdk/1.56.0 gl-python/3.11.13
+      - google-genai-sdk/1.56.0 gl-python/3.12.11
     method: POST
     uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:streamGenerateContent?alt=sse
   response:
     body:
       string: "data: {\"candidates\": [{\"content\": {\"parts\": [{\"functionCall\":
         {\"name\": \"weather_forecast\",\"args\": {\"city\": \"New York\"}},\"thoughtSignature\":
-        \"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\"}],\"role\":
+        \"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\"}],\"role\":
         \"model\"},\"finishReason\": \"STOP\",\"index\": 0,\"finishMessage\": \"Model
         generated function call(s).\"}],\"usageMetadata\": {\"promptTokenCount\":
-        133,\"candidatesTokenCount\": 16,\"totalTokenCount\": 232,\"promptTokensDetails\":
-        [{\"modality\": \"TEXT\",\"tokenCount\": 133}],\"thoughtsTokenCount\": 83},\"modelVersion\":
-        \"gemini-2.5-flash\",\"responseId\": \"crBVab6fBe6p_uMPycCNyAg\"}\r\n\r\n"
+        133,\"candidatesTokenCount\": 16,\"totalTokenCount\": 226,\"promptTokensDetails\":
+        [{\"modality\": \"TEXT\",\"tokenCount\": 133}],\"thoughtsTokenCount\": 77},\"modelVersion\":
+        \"gemini-2.5-flash\",\"responseId\": \"AXFYaf3jA7qj_uMPuYjYCQ\"}\r\n\r\n"
     headers:
       Alt-Svc:
       - h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
@@ -46,11 +46,11 @@ interactions:
       Content-Type:
       - text/event-stream
       Date:
-      - Wed, 31 Dec 2025 23:23:30 GMT
+      - Sat, 03 Jan 2026 01:29:37 GMT
       Server:
       - scaffolding on HTTPServer2
       Server-Timing:
-      - gfet4t7; dur=781
+      - gfet4t7; dur=741
       Transfer-Encoding:
       - chunked
       Vary:
@@ -94,7 +94,7 @@ interactions:
       Host:
       - generativelanguage.googleapis.com
       x-goog-api-client:
-      - google-genai-sdk/1.56.0 gl-python/3.11.13
+      - google-genai-sdk/1.56.0 gl-python/3.12.11
     method: POST
     uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:streamGenerateContent?alt=sse
   response:
@@ -104,7 +104,7 @@ interactions:
         \"STOP\",\"index\": 0,\"finishMessage\": \"Model generated function call(s).\"}],\"usageMetadata\":
         {\"promptTokenCount\": 165,\"candidatesTokenCount\": 14,\"totalTokenCount\":
         179,\"promptTokensDetails\": [{\"modality\": \"TEXT\",\"tokenCount\": 165}]},\"modelVersion\":
-        \"gemini-2.5-flash\",\"responseId\": \"dLBVaZqVHs2n_uMPx4K9wAw\"}\r\n\r\n"
+        \"gemini-2.5-flash\",\"responseId\": \"AnFYab6FA-6p_uMPycCNyAg\"}\r\n\r\n"
     headers:
       Alt-Svc:
       - h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
@@ -113,11 +113,11 @@ interactions:
       Content-Type:
       - text/event-stream
       Date:
-      - Wed, 31 Dec 2025 23:23:32 GMT
+      - Sat, 03 Jan 2026 01:29:38 GMT
       Server:
       - scaffolding on HTTPServer2
       Server-Timing:
-      - gfet4t7; dur=1731
+      - gfet4t7; dur=443
       Transfer-Encoding:
       - chunked
       Vary:
@@ -164,7 +164,7 @@ interactions:
       Host:
       - generativelanguage.googleapis.com
       x-goog-api-client:
-      - google-genai-sdk/1.56.0 gl-python/3.11.13
+      - google-genai-sdk/1.56.0 gl-python/3.12.11
     method: POST
     uri: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:streamGenerateContent?alt=sse
   response:
@@ -173,7 +173,7 @@ interactions:
         \"model\"},\"finishReason\": \"STOP\",\"index\": 0}],\"usageMetadata\": {\"promptTokenCount\":
         192,\"candidatesTokenCount\": 1,\"totalTokenCount\": 193,\"promptTokensDetails\":
         [{\"modality\": \"TEXT\",\"tokenCount\": 192}]},\"modelVersion\": \"gemini-2.5-flash\",\"responseId\":
-        \"dbBVaY62Au6p_uMPycCNyAg\"}\r\n\r\n"
+        \"AnFYaZCxLt63_uMP172v6Q0\"}\r\n\r\n"
     headers:
       Alt-Svc:
       - h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
@@ -182,11 +182,11 @@ interactions:
       Content-Type:
       - text/event-stream
       Date:
-      - Wed, 31 Dec 2025 23:23:33 GMT
+      - Sat, 03 Jan 2026 01:29:38 GMT
       Server:
       - scaffolding on HTTPServer2
       Server-Timing:
-      - gfet4t7; dur=242
+      - gfet4t7; dur=413
       Transfer-Encoding:
       - chunked
       Vary: