jeffhandley

Unmatched Tool Arguments: Cross-SDK Behavior Report

Context

Issue #1508 in the C# MCP SDK reports that when an AI model calls a tool with arguments that don't match any declared parameter (e.g., sending phase when the tool defines taskId, update, and markComplete), the extra arguments are silently dropped. Both the model and the backend proceed without any signal that arguments were ignored, potentially leading to incorrect behavior.

This report investigates how each official MCP SDK (Tier 1 and Tier 2) plus FastMCP (PrefectHQ) handles this scenario across five dimensions:

1. Code Implementation — Where in the code is the behavior controlled?
2. Issue/PR Discussion — Has this behavior been discussed in issues or PRs?

jeffhandley

let lastTweet = null,
    lastReply = null,
    lastRetweet = null,
    lastFollower = null,
    lastConversation = null;

const initialBackoff = 10000;
const backoffIncrease = 5000;
let backoff = initialBackoff;

jeffhandley

# Yes, I hate having to type "./" _that_ much.

New-Alias -Name "build" -Value BuildRuntime

function BuildRuntime {
    $root = $((git rev-parse --show-toplevel 2> $Null) ?? "").Replace("\", "/")
    $runtime = (Resolve-Path "~/git/dotnet/runtime").Path.Replace("\", "/")

    if ($root -eq $runtime) {
        & "~/git/dotnet/runtime/build.cmd" $ARGS

jeffhandley

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;

namespace Scanner
{
    class Program
    {

jeffhandley

var strickland = require("strickland");
var validate = strickland.default;
var required = strickland.required;
var length = strickland.length;
var minLength = strickland.minLength;
var form = strickland.form;

var data = {
    name: '',
    phones: [

jeffhandley

<style>
my-custom-class:before {
  top: 0px;
  /* this renders fine */
}

my-custom-class::before {
  top: 0px;
  /* this css class is not rendered */
}

jeffhandley

function View({ loading, error, ...otherProps }) {
  if (loading) {
    return (<Loading />);
  }
  
  if (error) {
    return (<Error error={error} />);
  }
  
  return (<MyLoadedComponent {...otherProps} />);

jeffhandley

/* NameDisplay.js */
import ReactPropTypes from 'prop-types';

const NameDisplay = ({name}) => (
    <div>
        <div>
            First Name: {name.first}
        </div>
        <div>
            Last Name: {name.last}

jeffhandley

function loadCameraRoll(url, max, done) {
    url = url || "https://graph.microsoft.com/v1.0/me/drive/special/cameraRoll/children";
    max = max || 200;

    console.log('LOADING PHOTOS');

    $.ajax({
        url: url,
        dataType: "json",
        headers: { "Authorization": "Bearer " + window.token },

jeffhandley

document.querySelectorAll("#channel_page_all_members a.lazy.member_preview_link.member_image.thumb_20")
  .forEach(function(member) {
    window.open(member.dataset.original.replace(/^url\(\'(.*)-48\'\)$/, "$1-128"));
  });