The problem

You keep four windows open to do one job. A terminal for the shell. A second terminal for docker logs -f. A third for htop. A browser tab for whatever dashboard someone installed on the box. Each of them logs in separately, each one asks for the key passphrase again, and none of them knows what the others are looking at.

Phosphor opens one SSH connection per host and multiplexes everything through it — the interactive shell, container logs, docker commands, /proc snapshots, SFTP transfers, port forwards. One login. One tunnel through your proxy. One place where the state lives.

And because that state is already in the app, it also exposes an MCP server: Claude Code and Claude Desktop can use your servers through your connections, your keys and your access policy — with every call written to an audit log.

What it does

Docker, without leaving the terminal

The container list is a sidebar, not a separate app. Inspect, stats, mounts, environment and live logs with --tail and a filter, streamed over the SSH connection you already have. Environment values whose name looks like a secret (PASS, KEY, TOKEN, SECRET) are masked in the UI and never copied into the audit log.

No Docker Engine API to expose, no socket to tunnel: it shells out to docker with JSON output, which works on every box where Docker already runs.

Metrics that cost one channel

Per-core load, memory with the cache broken out, disks, network, and per container CPU and memory — from /proc snapshots taken over a single long-lived channel. No agent to install on the server, no swarm of exec channels. Polling stops when the window is hidden, and every buffer has a ceiling.

Hosts, groups and tags

One group per host, as many tags as you like. The group carries the settings — how to reach it, which key, which theme, what MCP is allowed to do — and tags are just for finding things. Import ~/.ssh/config and keep going.

Unlock with a fingerprint

Phosphor has no account and no password of its own. There is a profile on this Mac, and your fingerprint opens it. Passwords, passphrases and TOTP seeds live in the Keychain behind biometrics; keys can live in the Secure Enclave, where they cannot be copied off the machine at all. Risky actions ask again.

A new server, set up by a recipe

Connect to a fresh box and Phosphor probes it: what is installed, what is listening, whether anyone has been here before. If it is empty, it offers a recipe — packages and unattended upgrades, Docker with log size caps, nginx, certbot, a firewall that only opens 22/80/443, and finally disabling password login. Every step is idempotent, every step shows the exact commands, and the lockout guard means password login is closed only after a second key-based connection has proved it works.

Keys you can actually see

authorized_keys as a table instead of a text file: fingerprints computed locally, weak RSA flagged, options shown, disabled entries kept as comments. The key you are currently connected with cannot be removed without an explicit confirmation, writes are atomic, and a backup stays on the server.

Files on both sides

Two panes, drag between them or in from Finder. Same SSH connection, same proxy. A dropped transfer resumes where it stopped.

Make it yours

Themes are plain JSON in themes/ — keep them in git, trade them with people, import .itermcolors, alacritty and base16. Palette, font, ligatures, line height, background image, scanlines, glow, vignette, window opacity. Bind a theme to a group so production is unmistakably red.

And there is a cat in the corner. Or a sugar glider. It sleeps while the app is locked, it never covers your output, and one switch turns it off forever.

Give an agent your servers without giving it your keys

Phosphor is also a Model Context Protocol server. Register one command and Claude Code, Claude Desktop, Cursor or any other MCP client can list your hosts, read metrics, inspect containers, follow logs and — when you allow it — run commands, restart containers, manage authorized_keys, and add, change or remove hosts in your own list. Anything that edits the list asks you first, in every mode.

The difference from handing a model a shell: the app holds the connection, the agent holds nothing.

claude mcp add phosphor /Applications/Phosphor.app/Contents/MacOS/phosphor-mcp

In the MCP registry it is io.github.Kirusshenkin/phosphor; every release also ships a .mcpb bundle with a published SHA-256 for clients that install that way.

Thirteen tools, seven of them read-only. Every host starts disabled — nothing is reachable until you choose read-only, confirm or full for it, and production servers are meant to stay read-only. A compromised server can put anything it likes into a log line the model reads; it still cannot grant itself a mode, get past the deny-list, or erase the record of trying.

Full details: docs/MCP.md — tool catalogue, policy, audit, and the exact error the agent gets when the app is closed, locked or refusing.

Principles

No integrations. The only network traffic the app makes is SSH to your own servers and the update feed. No telemetry, no accounts, no third-party services, nothing phoning home.

Secrets stay secret. Never in a log line, a crash report, an MCP audit entry or an error message. Terminal scrollback is not written to disk by default.

Errors tell you what to do. "Could not connect" is a bug. "The proxy at 127.0.0.1:10808 is not answering — is V2Box running?" is an error message. The app distinguishes a dead proxy from an unreachable server from a refused credential, because otherwise diagnosis is guesswork.

It stays fast because it is open all day. Bytes from the network are batched into ~16 ms windows before they reach the emulator, the draw path allocates nothing, every buffer is bounded, polling stops when the window is not visible, and animations only ever touch transform and opacity.

Strict Swift 6 concurrency, in every target, with no escape hatches. Network, parsing and disk work live in actors; only view models are on the main actor.

Two languages. English and Russian, both through a String Catalog. Not one hardcoded interface string — a linter checks.

Status

Builds, runs, 179 tests green. Eleven screens: lock, hosts, terminal with persistent sessions, files, Docker, monitor, keys, provisioning, AI activity and settings. Interface in Russian and English.

What works against a real server: SSH over one multiplexed connection per host, container listing with actions and streaming logs, /proc metrics, reading and editing authorized_keys, provisioning recipes, both file panes, and an interactive shell that rides the same socket.

MCP works end to end: an phosphor-mcp shim ships inside the bundle, speaks JSON-RPC over stdio and proxies to a local socket the app owns. Every host starts disabled, writes need a decision from a person, a deny-list overrides every mode, and the audit log has no writing tool — the model can act but cannot erase its trail.

Hosts import from ~/.ssh/config, from known_hosts and from a Termius vault, whose plaintext dump is deleted once the hosts are inside the encrypted profile.

What is not built yet: the native Citadel transport (the process-based one is tested and works), the pet in the corner, and in-app updates through Sparkle.

Idle CPU is zero — no timers, polling pauses when the window is in the background.

Install

curl -fsSL https://github.com/Kirusshenkin/terminalOs/releases/latest/download/Phosphor.zip -o Phosphor.zip
unzip -q Phosphor.zip -d /Applications
xattr -dr com.apple.quarantine /Applications/Phosphor.app

Or download Phosphor.zip from the release page and drag the app into Applications.

macOS will warn you the first time. The app is ad-hoc signed — there is no Apple Developer certificate behind it — so everything downloaded from the internet lands in quarantine. This is not damage:

1. Double-click the app, dismiss the warning.
2. System Settings → Privacy & Security → scroll down → Open Anyway.
3. Confirm. It never asks again.

The xattr command above does the same thing in one step.

Every release ships SHA256SUMS.txt; verify with shasum -a 256 -c SHA256SUMS.txt.