fix(gemini): sanitize tool schemas for Google providers

agent/gemini_cloudcode_adapter.py

@@ -39,6 +39,7 @@ from typing import Any, Dict, Iterator, List, Optional
 import httpx
 
 from agent import google_oauth
+from agent.gemini_schema import sanitize_gemini_tool_parameters
 from agent.google_code_assist import (
     CODE_ASSIST_ENDPOINT,
     FREE_TIER_ID,
@@ -205,7 +206,7 @@ def _translate_tools_to_gemini(tools: Any) -> List[Dict[str, Any]]:
             decl["description"] = str(fn["description"])
         params = fn.get("parameters")
         if isinstance(params, dict):
-            decl["parameters"] = params
+            decl["parameters"] = sanitize_gemini_tool_parameters(params)
         declarations.append(decl)
     if not declarations:
         return []

agent/gemini_native_adapter.py

@@ -27,6 +27,8 @@ from typing import Any, Dict, Iterator, List, Optional
 
 import httpx
 
+from agent.gemini_schema import sanitize_gemini_tool_parameters
+
 logger = logging.getLogger(__name__)
 
 DEFAULT_GEMINI_BASE_URL = "https://generativelanguage.googleapis.com/v1beta"
@@ -253,7 +255,7 @@ def _translate_tools_to_gemini(tools: Any) -> List[Dict[str, Any]]:
             decl["description"] = description
         parameters = fn.get("parameters")
         if isinstance(parameters, dict):
-            decl["parameters"] = parameters
+            decl["parameters"] = sanitize_gemini_tool_parameters(parameters)
         declarations.append(decl)
     return [{"functionDeclarations": declarations}] if declarations else []
 

agent/gemini_schema.py

@@ -0,0 +1,85 @@
+"""Helpers for translating OpenAI-style tool schemas to Gemini's schema subset."""
+
+from __future__ import annotations
+
+from typing import Any, Dict, List
+
+# Gemini's ``FunctionDeclaration.parameters`` field accepts the ``Schema``
+# object, which is only a subset of OpenAPI 3.0 / JSON Schema.  Strip fields
+# outside that subset before sending Hermes tool schemas to Google.
+_GEMINI_SCHEMA_ALLOWED_KEYS = {
+    "type",
+    "format",
+    "title",
+    "description",
+    "nullable",
+    "enum",
+    "maxItems",
+    "minItems",
+    "properties",
+    "required",
+    "minProperties",
+    "maxProperties",
+    "minLength",
+    "maxLength",
+    "pattern",
+    "example",
+    "anyOf",
+    "propertyOrdering",
+    "default",
+    "items",
+    "minimum",
+    "maximum",
+}
+
+
+def sanitize_gemini_schema(schema: Any) -> Dict[str, Any]:
+    """Return a Gemini-compatible copy of a tool parameter schema.
+
+    Hermes tool schemas are OpenAI-flavored JSON Schema and may contain keys
+    such as ``$schema`` or ``additionalProperties`` that Google's Gemini
+    ``Schema`` object rejects.  This helper preserves the documented Gemini
+    subset and recursively sanitizes nested ``properties`` / ``items`` /
+    ``anyOf`` definitions.
+    """
+
+    if not isinstance(schema, dict):
+        return {}
+
+    cleaned: Dict[str, Any] = {}
+    for key, value in schema.items():
+        if key not in _GEMINI_SCHEMA_ALLOWED_KEYS:
+            continue
+        if key == "properties":
+            if not isinstance(value, dict):
+                continue
+            props: Dict[str, Any] = {}
+            for prop_name, prop_schema in value.items():
+                if not isinstance(prop_name, str):
+                    continue
+                props[prop_name] = sanitize_gemini_schema(prop_schema)
+            cleaned[key] = props
+            continue
+        if key == "items":
+            cleaned[key] = sanitize_gemini_schema(value)
+            continue
+        if key == "anyOf":
+            if not isinstance(value, list):
+                continue
+            cleaned[key] = [
+                sanitize_gemini_schema(item)
+                for item in value
+                if isinstance(item, dict)
+            ]
+            continue
+        cleaned[key] = value
+    return cleaned
+
+
+def sanitize_gemini_tool_parameters(parameters: Any) -> Dict[str, Any]:
+    """Normalize tool parameters to a valid Gemini object schema."""
+
+    cleaned = sanitize_gemini_schema(parameters)
+    if not cleaned:
+        return {"type": "object", "properties": {}}
+    return cleaned