mcp-testing

mcp-testing is a skill for Claude Code from umbraco/Umbraco-MCP-Base. It costs 34 tokens per session (1,186 once invoked), scanned A, original, MIT.

A guide to writing evaluation tests for MCP tools using an AI agent. These tests ask a language model to use the tools and check whether the resulting workflow works as intended.

In plain words
What is it for?
Use it when creating or debugging LLM-based acceptance tests for MCP tools; use a separate integration-test process for regular integration tests.
Why use it?
It helps test how tools behave in real agent-driven use, which ordinary integration tests do not measure.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is rootDir: "../..",.

Part of the umbraco-mcp-skills plugin — 13 skills, 7 agents shipped together

Good fit Use it when creating or debugging LLM-based acceptance tests for MCP tools; use a separate integration-test process for regular integration tests.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/umbraco/Umbraco-MCP-Base
agentmods
npx agentmods add skills/umbraco/umbraco-mcp-base/mcp-testing

Made for: Claude Code.

Or install umbraco-mcp-skills, the plugin that ships this one along with the rest of its 13 skills, 7 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for mcp-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/umbraco/umbraco-mcp-base/mcp-testing/github.svg)](https://agentmods.dev/skills/umbraco/umbraco-mcp-base/mcp-testing)
Your own site
<a href="https://agentmods.dev/skills/umbraco/umbraco-mcp-base/mcp-testing"><img src="https://agentmods.dev/badge/skills/umbraco/umbraco-mcp-base/mcp-testing/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for mcp-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/umbraco/umbraco-mcp-base/mcp-testing"><img src="https://agentmods.dev/badge/skills/umbraco/umbraco-mcp-base/mcp-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,186 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00034 $0.01186
Opus 5.5 $0.00014 $0.00474
Sonnet 5.5 $0.00007 $0.00237
Haiku 4.5 $0.00003 $0.00119

Measured 2mo ago against content hash 6aac610f028b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcp-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/umbraco-mcp-skills/skills/mcp-testing/SKILL.md · 174 lines

How it starts

The opening of the file, as written. The whole thing — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCP Eval Testing Patterns

This skill loads eval testing patterns for MCP tools using @umbraco-cms/mcp-server-sdk/evals. Eval tests verify tools work correctly when driven by an LLM agent.

For integration tests, use /build-tools-tests instead.

When to Use

Use this skill when:

  • Creating eval/acceptance tests for MCP tools
  • Verifying tools work correctly in LLM-driven workflows
  • Debugging eval test failures

Setup

Eval tests live in tests/evals/ with a dedicated Jest config. The setup file is loaded automatically via setupFilesAfterEnv — test files do NOT need to import it.

tests/evals/helpers/e2e-setup.ts

import path from "path";
import { configureEvals, ClaudeModels } from "@umbraco-cms/mcp-server-sdk/evals";

configureEvals({
  mcpServerPath: path.resolve(process.cwd(), "dist/index.js"),
  mcpServerName: "my-mcp-server",
  serverEnv: { USE_MOCK_API: "true" },
  defaultModel: ClaudeModels.Haiku,
  defaultMaxTurns: 10,
  defaultMaxBudgetUsd: 0.25,
  defaultTimeoutMs: 60000,
});

tests/evals/jest.config.ts

import type { Config } from "jest";

const config: Config = {
  preset: "ts-jest/presets/js-with-ts-esm",
  testEnvironment: "node",
  extensionsToTreatAsEsm: [".ts"],
  rootDir: "../..",
  testMatch: ["<rootDir>/tests/evals/**/*.test.ts"],
  setupFilesAfterEnv: ["<rootDir>/tests/evals/helpers/e2e-setup.ts"],
  maxConcurrency: 1,
  maxWorkers: 1,
  testTimeout: 120000,
};

export default config;

Test Pattern

// tests/evals/entity-crud.test.ts
import { describe, it } from "@jest/globals";
import {
  runScenarioTest,
  setupConsoleMock,
  getDefaultTimeoutMs,
} from "@umbraco-cms/mcp-server-sdk/evals";

describe("entity evals", () => {
  setupConsoleMock();

  it(
    "should complete workflow",
    runScenarioTest({
      prompt: `Complete these tasks:
1. Create an item named "Test"
2. Delete the item
3. Say "Workflow completed"`,
      tools: ["create-item", "delete-item"],
      requiredTools: ["create-item", "delete-item"],
      successPattern: "Workflow completed",
    }),
    getDefaultTimeoutMs()
  );
});

Read the full file on GitHub · 174 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2mo ago First seen · 174 lines · 34 tokens per session scan A 6aac610f028b

Subscribe to this mod's changes

mcp-testing is a skill published in the GitHub repository umbraco/Umbraco-MCP-Base (2 stars, last pushed yesterday), licensed MIT. It adds 34 tokens to every session and 1,186 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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