Why Cinch

OSC 52 — good until it isn’t

Most modern terminals support clipboard sharing via OSC 52 escape sequences. For interactive SSH sessions in a cooperating terminal, it works well.

But the escape sequence approach breaks in a surprisingly large number of real-world situations:

Scenario	OSC 52 status
Interactive SSH in iTerm2 / Ghostty	Works
SSH inside tmux / screen	Broken — multiplexer intercepts the sequence
Nested SSH hops	Broken — escape codes rarely survive the jump
Docker exec / docker attach	Broken — no terminal escape passthrough
Vim / Neovim inside SSH	Often flaky or requires complex config
CI/CD runner (GitHub Actions, etc.)	Broken — non-interactive, no PTY
Older SSH servers (OpenSSH < 7.2)	Broken — clipboard support not enabled

Tip

If you have a single SSH session in a modern terminal and no tmux, OSC 52 is fine. Use it. Cinch is for when that’s not your world.

How Cinch is different

Cinch is a local-first remote clipboard for developer context. It keeps clipboard history on your machine, gives AI tools a read-only MCP view when you configure it, and syncs through HTTP only when you ask it to move clips across machines:

1. cinch send encrypts the clip on your device and sends it to a relay server over HTTPS.
2. The relay holds the ciphertext in Postgres until it is pulled.
3. cinch pull (or the Cinch desktop app) retrieves it over WebSocket for real-time delivery.

Because it’s HTTP, it works everywhere:

• Across tmux, screen, and any multiplexer
• From inside Vim or Neovim without special terminal config
• Through any number of SSH hops
• In Docker containers or CI runners (outbound HTTPS only)
• In non-interactive shells (no PTY required)

Bidirectional

OSC 52 is one-way (terminal → clipboard). Cinch supports both directions:

cinch send   # local → relay → fleet
cinch pull   # relay → local clipboard

Send from a script running on a remote box. Pull the result on your laptop. Or the reverse — send from your laptop, pull inside a container.

Self-hosted by default

Cinch is designed to be self-hosted. The relay is a single Go binary (or a Docker image) you run on any server. Your clips never leave infrastructure you control unless you opt into the hosted relay.

The protocol is documented in Relay Protocol. Anyone can inspect what the relay stores and for how long.

AI workflows stay explicit

cinch mcp is read-only, and local-only by default (fleet-scoped reads require CINCH_MCP_FLEET=1). cinch ai fix only sends context to an AI provider when you explicitly run it without --no-send and have configured a provider. Ordinary clipboard sync does not call AI providers.