"An introduction to prompt engineering" matching MCP connectors:

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

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.

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

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

Pay-per-call MCP server. Vetted human experts review AI-generated content (text, images, video, audio, social posts), audit reasoning chains, run prepublish safety checks, and gate high-stakes actions for human approval. 7 paid tools at $1.00 each plus 4 free tools (list_offerings, list_expert_profiles, get_result, verify_certificate). Payment via x402, USDC on Base mainnet. Approved outputs receive an on-chain Taste content certificate downstream agents verify before consuming.

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

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.

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.

Test-inbox API for email and SMS: create inboxes, long-poll messages, extract OTPs and links. 34 tools; bearer auth with an mfx_ API key (free tier).

MCP server providing access to the Scorecard API to evaluate and optimize LLM systems.

MCP server for AI access to SmartBear tools, including BugSnag, Reflect, Swagger, PactFlow, QTM4J.

## Skill Catalog The library contains 42 public skills organized by Rails development concern. | Category | Examples | |----------|----------| | Planning | `create-prd`, `generate-tasks`, `plan-tickets` | | Testing | `plan-tests`, `write-tests`, `test-service`, `triage-bug` | | Code quality | `code-review`, `respond-to-review`, `security-check`, `refactor-code` | | Architecture and DDD | `define-domain-language`, `review-domain-boundaries`, `model-domain`, `review-architecture` | | Rails imple

Direct access to Cypress tests results and accessibility reports in your AI workflow.

Scan GitHub-hosted AI skills for vulnerabilities: prompt injection, malware, OWASP LLM Top 10.

Scan an MCP server for EU AI Act Art. 50, tool quality, OAuth hygiene & security before shipping.

A paid remote MCP for Unity-MCP, built to return verdicts, receipts, usage logs, and audit-ready JSO

A paid remote MCP for AI SDK benchmark dashboard, built to return verdicts, receipts, usage logs, an