StartupSan Francisco, CA · Est. 2024 · Y Combinator (Summer 2024)
cmux
Open-source Ghostty-based macOS terminal for running many AI coding agents at once, by Manaflow.
cmux is a native macOS terminal, built in Swift and AppKit on libghostty, for multitasking across AI coding agents. It is made by Manaflow (YC Summer 2024), which its YC profile calls an open-source applied AI lab building next-gen devtools. Features include notification rings and a panel that flag panes needing agent attention, and vertical tabs showing git branch, PR status, ports and the latest notification. It also has a scriptable in-app browser, SSH workspaces, a one-command Claude Code teammate mode, and a CLI and socket API for automation. The terminal is GPL-3.0-or-later, and parts of the server code are BUSL-1.1.
People
Founder & CEO, cmux / Manaflow
Harness engineering
Engineer, Manaflow
Harness engineering
Neighbours in the directory
San Francisco, CA · Est. 2023
Devin, the AI software engineer, and the Windsurf IDE.
Cognition builds Devin, an autonomous AI software engineer that plans and executes engineering tasks end-to-end, and acquired the Windsurf agentic IDE in 2025. One of the defining startups of the coding-agent wave.
~$10.2B valuation (Sep 2025)
San Francisco, CA · Est. 2023
The integration layer: hundreds of managed tools your agents can call.
Composio handles auth, schemas, observability and reliability for the external SaaS tools an agent uses — 'plumbing for agentic actions' across Slack, GitHub, Salesforce and 250+ other surfaces.
Est. 2024
A registry and toolchain for MCP servers.
Smithery indexes and helps deploy MCP (Model Context Protocol) servers — a distribution layer for the tool ecosystem agents connect to.
Connections
Relations from the Harness Hub knowledge graph, as charted in the State of Harness reports.
Built on · 1
- Claude CodeProject
Sources
- GitHub repo and README
- Y Combinator profile: Manaflow
- LICENSE (GPL-3.0-or-later; BUSL-1.1 server dirs)
Verified Oct 29, 2026