"Building voice agents and controlling SIP phones" matching MCP connectors:

Test-inbox API for email and SMS: create inboxes, long-poll messages, extract OTPs and links.

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

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.

Check AI work against requirements and return structured verdicts, findings, and repair steps.

Voice-powered bug reporting with 13 MCP tools. Record bugs by talking; let AI find and fix them.

One-cent x402 and MCP readiness checks plus fixed-price marketplace launch packs.

Generate deterministic placeholder image URLs and packs for docs, staging, testing, and AI agents.

Test the voice agents you run: scored transcripts, pass/fail verdicts, latency and WER metrics.

Machine-readable taxonomy of 100+ AI system failure modes spanning factuality, alignment, planning, code generation, and instruction following.

Scan URLs for WCAG 2.1 violations, generate AI fixes, and produce VPAT 2.5 compliance reports.

Webhook relay for AI agents: keyless quickstart, event inspection, replay, mock payloads.

MCP-native AI evaluation: rubric audits, eval suites, and proof reports for AI/LLM output.

Query Checkly synthetic monitoring — checks, statuses, results, alerts, reporting and dashboards.

Read-only verifier for 25 ProofRelay MCP tools and non-confidential evidence bundles.

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

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.

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.