Assess
"One API to use any LLM with every MCP tool" — a proxy service that abstracts away MCP server management entirely.
Why It Matters
OpenTools (opentools.com) takes a radically different approach: instead of installing and running MCP servers locally, you call their OpenAI-compatible API and they handle tool execution on their infrastructure. No personal API keys needed for individual tools — unified billing, token-at-cost pricing, and backwards compatibility with traditional function calling. They maintain an MCP Server Registry at opentools.com/registry. This is MCP-as-a-service at its most extreme.
Strengths
- Zero local installation — no npm, no Docker, no config files
- OpenAI-compatible API means drop-in integration with existing code
- Unified billing simplifies cost management across many tools
- Abstracts away all MCP server lifecycle management
- Backwards compatible with traditional function calling patterns
Limitations
- Adds a proxy layer between your LLM and tools — latency and reliability dependency
- Registry size and vetting process are not transparently documented
- Relatively new platform with limited track record
- Not open-source despite the name
Risks
- Centralizing all MCP tool execution through a single third-party API creates a high-value attack target and single point of failure
- Every tool call and its data routes through OpenTools' infrastructure — the privacy implications for enterprise use are significant
- "Token-at-cost" pricing is opaque: you're trusting their cost accounting without visibility into underlying provider costs
- The proxy model means you can't inspect, audit, or customize the MCP servers running your tools
- If OpenTools goes down, changes pricing, or shuts down, every integration breaks simultaneously with no self-hosted fallback