Outcome. You can explain MCP host/client/server responsibilities, distinguish tool interoperability from agent delegation, and decide when one agent is better than several.
The Model Context Protocol (MCP) standardizes how a host application discovers and exchanges information with servers that expose tools, resources, and prompts. A host creates clients that connect to servers, negotiates capabilities, and decides what becomes available to the model. MCP can reduce one-off integration work; it does not decide whether a tool is trustworthy, grant authorization, sandbox code, or guarantee that the model will call tools correctly.
A multi-agent system delegates work among multiple model-driven workers or roles. That is a separate architecture choice. One coordinator might assign research, coding, and review tasks, but the system must move context, resolve conflicts, aggregate results, control shared tools, and stop. More agents can parallelize independent work or add specialized checks; they also add cost, latency, context loss, correlated mistakes, and coordination failure.
Start with one agent or a fixed workflow. Add another worker only when a measured bottleneck—parallel work, isolated permissions, distinct context, or independent review—justifies the coordination overhead. Do not use “multi-agent” as a synonym for “advanced.”
Mental model. MCP standardizes connections; delegation divides work. Neither substitutes for permissions, evaluation, or orchestration.
Evidence trail — reviewed 23 July 2026. Latest MCP specification: https://modelcontextprotocol.io/specification/latest and architecture: https://modelcontextprotocol.io/docs/learn/architecture. ReAct provides one-agent action loops: https://arxiv.org/abs/2210.03629.
Baseline one agent with retrieval and a rubric. Add a separate researcher only if source gathering is the bottleneck; add an independent reviewer only if it catches measured errors. Give workers scoped tools, pass structured handoffs, cap rounds, and compare quality, latency, and cost with the baseline.