fix(core): Sanitize tool parameters to fix 400 API errors (#3300)

packages/core/src/tools/mcp-client.ts

@@ -14,13 +14,8 @@ import {
 import { parse } from 'shell-quote';
 import { MCPServerConfig } from '../config/config.js';
 import { DiscoveredMCPTool } from './mcp-tool.js';
-import {
-  CallableTool,
-  FunctionDeclaration,
-  mcpToTool,
-  Schema,
-} from '@google/genai';
-import { ToolRegistry } from './tool-registry.js';
+import { CallableTool, FunctionDeclaration, mcpToTool } from '@google/genai';
+import { sanitizeParameters, ToolRegistry } from './tool-registry.js';
 
 export const MCP_DEFAULT_TIMEOUT_MSEC = 10 * 60 * 1000; // default to 10 minutes
 
@@ -384,31 +379,3 @@ async function connectAndDiscover(
     }
   }
 }
-
-/**
- * Sanitizes a JSON schema object to ensure compatibility with Vertex AI.
- * This function recursively processes the schema to remove problematic properties
- * that can cause issues with the Gemini API.
- *
- * @param schema The JSON schema object to sanitize (modified in-place)
- */
-export function sanitizeParameters(schema?: Schema) {
-  if (!schema) {
-    return;
-  }
-  if (schema.anyOf) {
-    // Vertex AI gets confused if both anyOf and default are set.
-    schema.default = undefined;
-    for (const item of schema.anyOf) {
-      sanitizeParameters(item);
-    }
-  }
-  if (schema.items) {
-    sanitizeParameters(schema.items);
-  }
-  if (schema.properties) {
-    for (const item of Object.values(schema.properties)) {
-      sanitizeParameters(item);
-    }
-  }
-}