The AI agent runtime,
not another wrapper.
Plexo is the open-source platform underneath everything Joeybuilt ships. Semantic memory that persists, domain reasoning through SCL, and agents that learn from every task.
Self-hostable in minutes. No vendor lock-in.
The platform
Built for agents that ship.
Plexo isn't a chat UI with tools bolted on. It's a runtime, a memory layer, and a marketplace ? designed to let agents accumulate capability over time.
Semantic memory
Atomic facts, HNSW vector indexing, append-only history. Agents remember what you told them and what they learned ? across sessions, across products.
Domain reasoning
The Semantic Context Lattice (SCL) lets agents reason within bounded domains instead of guessing in the dark. Add a domain, watch quality jump.
Persistent agents
Durable Inngest workflows back every task. Multi-step plans survive restarts, browser refreshes, and model failures. Resume from any step.
Intelligent model routing
Route by cost, capability, or latency. Mix Anthropic, OpenAI, local models, anything reachable. Skills declare what they need; Plexo picks the right model.
MCP-native
First-class Model Context Protocol support. Connect Anthropic's official MCP servers or build your own with the Pex extension protocol.
Self-hostable
Postgres + pgvector, Inngest, Valkey. Standard tools, standard ports. Deploy on a VPS, Kubernetes, or your laptop. Anywhere docker compose runs.
Vocabulary
Six words. Whole system.
Plexo's entire API is built on these primitives. Learn them once.
- Tool
- An atomic action an agent can invoke. Read a file, call an API, run a query.
- Skill
- A reusable capability bundle. Wraps tools, prompts, and policy into something installable.
- Agent
- A configured persona with a memory, a model, and a Skill loadout.
- Connection
- A credentialed link to an external service. OAuth handled, tokens stored encrypted.
- Channel
- Where agents speak. Web, Telegram, email, Slack ? the same agent, the same memory.
- Work
- An output. Files, messages, tasks completed. Every Work is traceable to the agent and tools that produced it.
Marketplace
Install capability the way you install packages.
Browse community Skills, Agents, and Tools. Install with one click. Version, fork, contribute back. Connections live in Settings ? your credentials stay yours.
Open source
AGPL-3.0. Open forever.
Plexo is AGPL-3.0 — strong copyleft for the network era. Fork it, run it, ship modifications. If you offer it as a service, share the source. Plexo stays open, forever.