phi-agent
A Rust runtime framework for building AI agents that handles orchestration, sessions and streaming while leaving tools, prompts and domain logic to the developer, with MCP support and optional multi-agent and shell tools behind feature flags.
phi-agent is a Rust framework for building AI agent runtimes. It ships with no application tools built in - no web search, database connector or code executor - and instead provides the orchestration layer: sessions, event streaming and a builder for wiring in tools, prompts and renderers.
The project is split into layered crates: agent-base is a lightweight runtime kernel exposing an LLM client and a Tool trait; agent-works adds a toolbox for MCP, skills and focus; and phi-agent is the full framework with a CLI binary. File access and MCP support are enabled by default, while shell execution, multi-agent spawning and browser automation are opt-in feature flags.
It is aimed at Rust developers who want to assemble a custom agent runtime from small, independently versioned crates rather than adopt an all-in-one framework.