diff --git a/src/core/tools/__tests__/useMcpToolTool.spec.ts b/src/core/tools/__tests__/useMcpToolTool.spec.ts
index 130047ae15..7fbd120fcb 100644
--- a/src/core/tools/__tests__/useMcpToolTool.spec.ts
+++ b/src/core/tools/__tests__/useMcpToolTool.spec.ts
@@ -24,7 +24,7 @@ vi.mock("../../prompts/responses", () => ({
 vi.mock("../../../i18n", () => ({
 	t: vi.fn((key: string, params?: any) => {
 		if (key === "mcp:errors.invalidJsonArgument" && params?.toolName) {
-			return `Roo tried to use ${params.toolName} with an invalid JSON argument. Retrying...`
+			return `Failed to use ${params.toolName}: Invalid JSON argument provided. Please ensure the arguments are properly formatted JSON and try again.`
 		}
 		if (key === "mcp:errors.toolNotFound" && params) {
 			return `Tool '${params.toolName}' does not exist on server '${params.serverName}'. Available tools: ${params.availableTools}`
@@ -164,7 +164,7 @@ describe("useMcpToolTool", () => {
 
 			expect(mockTask.consecutiveMistakeCount).toBe(1)
 			expect(mockTask.recordToolError).toHaveBeenCalledWith("use_mcp_tool")
-			expect(mockTask.say).toHaveBeenCalledWith("error", expect.stringContaining("invalid JSON argument"))
+			expect(mockTask.say).toHaveBeenCalledWith("error", expect.stringContaining("Invalid JSON argument"))
 			expect(mockPushToolResult).toHaveBeenCalledWith("Tool error: Invalid args for test_server:test_tool")
 		})
 	})
diff --git a/src/i18n/locales/en/mcp.json b/src/i18n/locales/en/mcp.json
index 0200e26d22..fcb302de88 100644
--- a/src/i18n/locales/en/mcp.json
+++ b/src/i18n/locales/en/mcp.json
@@ -5,7 +5,7 @@
 		"invalid_settings_validation": "Invalid MCP settings format: {{errorMessages}}",
 		"create_json": "Failed to create or open .roo/mcp.json: {{error}}",
 		"failed_update_project": "Failed to update project MCP servers",
-		"invalidJsonArgument": "Roo tried to use {{toolName}} with an invalid JSON argument. Retrying...",
+		"invalidJsonArgument": "Failed to use {{toolName}}: Invalid JSON argument provided. Please ensure the arguments are properly formatted JSON and try again.",
 		"refresh_after_disable": "Failed to refresh MCP connections after disabling",
 		"refresh_after_enable": "Failed to refresh MCP connections after enabling",
 		"disconnect_servers_partial": "Failed to disconnect {{count}} MCP server(s). Check the output for details.",