"A tool or technique to improve prompt writing" matching MCP connectors:

Prompt evals over MCP: run a prompt on your dataset, score each output 1-5 with an LLM judge.

Evidence-gated task verification for AI agents. Decompose goals into acceptance criteria, attach proof (screenshot, curl, file), independent LLM judge accepts or rejects. 24 tools. Hosted remote MCP (streamable-http, OAuth 2.1 + DCR).

Free platform to test MCP clients without installing anything. Create mock tools with dynamic templates, configurable delays, conditions (if/then), and response sequences. Supports JSON-RPC 2.0 over Streamable HTTP. Built-in text_echo and json_echo tools. Rate-limited tiers: anonymous (5 calls/min, 1 mock tool), registered (10 calls/min, 4 mock tools), premium (60 calls/min, unlimited). Zero setup — no install, no registration required. More info: https://www.testmcp.dev

Check that your AI is being logical. Free tool that mathematically catches contradictions in agent reasoning. No account needed. Also offers paid guardrails that converts natural language to formal verification proofs, that anyone can check succinctly.

Promotion gate for AI agents: leakage audits, exact-statistics verdicts, and a live report card.

Hire a real human for real-world verification, product testing, AI output review, and errands.

Runs your code against a contract; returns HELD or BROKE at the exact input. Deterministic.

MCP server for the Fail Modes taxonomy — a knowledge base of AI system failure modes

Grade MCP servers A to F with the open behavioral litmus. npm: full toolset; hosted: lookups only.

A flock of AI users tests your deployed app and reports where real people get stuck, with fixes.

PQS scores any prompt before the model runs. 8 dimensions. 5 frameworks. Pre-flight, not post-hoc.

MCP-native AI browser testing for coding agents. Submit a URL + goal, get back action trail, bugs, screenshots, and WebM video your agent patches from directly. 43 tools, 12 AI evaluation personalities, combo tiers with auto-pause-on-bugs, throwaway email + SMS inboxes.

130+ QA & dev tools for AI agents: prompt injection, RAG testing, VLM eval, guardrails. Free.

MCP server for e-mail testing: create disposable inboxes, wait for delivery, and extract e-mail content or links - all from your AI agent or test automation workflow. Get a free API key on https://app.zyntra.app/

The world's first named AI prompt quality score. Score, optimize, and compare LLM prompts before they hit any model. Free tier available. Built on PEEM, RAGAS, G-Eval, and MT-Bench frameworks. x402-native on Base.

Validate up to 75,000 URLs per job (status, redirects, response times). OAuth 2.1.

Benchmark-first release surface with a read-only MCP endpoint and operator CLI.

End-to-end API testing — generate and run tests from OpenAPI, curl, Postman, or real user traffic.

Check if your MCP server is ready to publish on the MCP Registry, Smithery, or npm.

Drive real Android & iOS devices and web browsers from natural language for mobile + web QA. 145+ tools across device control, app management, automation sessions, browser automation, and flow recording / replay. Bearer-auth — get a token at robotactions.com → Profile → API Tokens.