Quark is now Sael
We renamed our protocol. Same streaming-first design, same goals, a name that does not collide with a dozen other things called Quark. Here is what Sael is and why it exists.
Short version: the protocol formerly called Quark is now Sael. Same design, same repo lineage, cleaner name. Old /quark links redirect to /sael.
Why rename
"Quark" is overloaded — a physics term, a German cheese, a desktop-publishing app, several crypto coins. For something we want people to search for and cite, a distinct name matters. Sael is short, pronounceable, and ours.
What Sael actually is
Sael is a streaming-first, source-available protocol (BUSL-1.1) for connecting AI agents to tools — the production successor to MCP. MCP is fine for desktop-style request/response. Under production load it cracks: no native streaming, no composition, no subscriptions, no backpressure, no capability security, nothing for multi-agent.
Sael builds those into the protocol, not the SDK:
- Streaming-first over a live WebSocket channel.
- Server-side composition — one request describes a whole pipeline; only the result returns.
- Parallel fan-out, delta streams, subscriptions.
- Signed capability tokens, session resume, heartbeat, cost tracking, W3C tracing.
- MessagePack binary frames, opt-in.
Adoption is incremental
Any existing MCP server runs through the Sael adapter with zero code changes. You adopt streaming and composition tool by tool, when you want them — not in a big-bang migration.
Status
v1.0 stable. SDKs for TypeScript and Go, with a reference server live (it powers the demo on the site). Source-available under BUSL-1.1; the spec text is CC BY-NC-ND. Commercial license on request.
Read the spec and try the live demo at unyly.org/sael.