Key Takeaways

An AI agent SaaS stack is a normal SaaS shell plus an agent layer: LLM access, orchestration, tool calling, memory, instructions, and evals.

Default to a thin orchestration layer (Vercel AI SDK) and a model gateway (the OpenRouter pattern); reach for LangGraph or CrewAI only when you need durable multi-agent graphs.

MCP is now a vendor-neutral standard under the Linux Foundation, and Forrester expects 30% of enterprise app vendors to ship their own MCP servers by the end of 2026.

Most SaaS agents don't need a vector database on day one; a peer-reviewed benchmark found neither RAG nor long context wins universally.