Dev Terminal Skill

Terminal automation that maintains PTY sessions across script executions. Run TUI applications, send keystrokes, capture screen output, and debug terminal apps – all with persistent state.

Setup

Start the server in a background terminal:

cd dev-terminal && npm install && ./server.sh &

Wait for the Ready message before running scripts.

Headed Mode (Optional)

For visual debugging, start with browser UI:

cd dev-terminal && ./server.sh --headed &

This opens a browser window showing all terminals in real-time. Useful for:

• Watching AI actions as they happen
• Manual intervention if needed
• Debugging TUI interactions

Writing Scripts

Run scripts inline using heredocs from the dev-terminal/ directory:

cd dev-terminal && npx tsx <<'EOF'
import { connect, sleep } from "./src/client.js";

const client = await connect();

// Create or get a named terminal
const term = await client.terminal("my-app", {
  command: "python",
  args: ["-m", "my_module"],
  cols: 120,
  rows: 40,
});

// Wait for app to start
await sleep(1000);

// Get screen snapshot
const snap = await term.snapshot();
console.log("=== SCREEN ===");
console.log(snap.text);

client.disconnect();
EOF

Shell Defaults

By default, terminals use:

• Shell: User’s default shell ($SHELL env var, e.g., zsh on macOS, bash on Linux)
• Mode: Login shell (-l flag) – loads full profile (~/.zprofile, ~/.bash_profile)

This means your shell aliases, PATH, and environment are available.

Override the shell:

// Use a specific shell
const term = await client.terminal("my-term", {
  command: "bash",
  args: ["-l"], // keep as login shell
});

// Non-login shell (only loads ~/.bashrc, not ~/.bash_profile)
const term = await client.terminal("my-term", {
  command: "bash",
  args: [], // no -l flag
});

// Run a command directly (not a shell)
const term = await client.terminal("my-term", {
  command: "python",
  args: ["-m", "my_app"],
});

SSH Remote Terminals

Connect to remote servers via SSH. The API is identical to local terminals.

import { connect } from "./src/client.js";
import * as fs from "fs";
import * as os from "os";
import * as path from "path";

const client = await connect();

// SSH with private key
const term = await client.terminal("remote-server", {
  ssh: {
    host: "192.168.1.100",
    username: "deploy",
    privateKey: fs.readFileSync(path.join(os.homedir(), ".ssh/id_rsa"), "utf8"),
  },
});

// SSH with password
const term = await client.terminal("remote-server", {
  ssh: {
    host: "example.com",
    username: "admin",
    password: "secret",
  },
});

// SSH with agent (uses SSH_AUTH_SOCK)
const term = await client.terminal("remote-server", {
  ssh: {
    host: "example.com",
    username: "admin",
    agent: process.env.SSH_AUTH_SOCK,
  },
});

// SSH with custom port and encrypted key
const term = await client.terminal("remote-server", {
  ssh: {
    host: "example.com",
    port: 2222,
    username: "admin",
    privateKey: fs.readFileSync("/path/to/key", "utf8"),
    passphrase: "key-passphrase",
  },
});

SSH Options:

Notes:

• SSH terminals don’t have a pid (it’s undefined)
• All Terminal methods work the same (write, key, snapshot, etc.)
• The remote shell is determined by the server, not local settings

Key Principles

1. Small scripts: Each script does ONE thing (start app, check screen, send key)
2. Observe output: Always check snapshot() to see current state
3. Descriptive names: Use "claude-monitor", "vim-edit", not "term1"
4. Terminals persist: disconnect() leaves terminals running for next script

Workflow Loop

1. Write a script to perform one action
2. Run it and observe the screen output
3. Evaluate – what’s displayed? Did it work?
4. Decide – send more input or task complete?
5. Repeat until done

Client API

const client = await connect();

// Get or create named terminal (uses default shell as login shell)
const term = await client.terminal("name");

// With options
const term = await client.terminal("name", {
  command: "python", // override shell/command
  args: ["-m", "my_app"], // override args (clears default -l flag)
  cols: 120,
  rows: 40,
  cwd: "/path/to/dir",
  env: { MY_VAR: "value" },
});

// List all terminal names
const names = await client.list();

// Close/kill a terminal
await client.close("name");

// Disconnect (terminals persist)
client.disconnect();

Terminal Methods

// Send raw input
await term.write("hello");

// Send special keys
await term.key("enter");
await term.key("up");
await term.key("ctrl+c");

// Send a line (adds Enter)
await term.writeLine("ls -la");

// Get screen state
const snap = await term.snapshot();
console.log(snap.text); // Plain text (no ANSI codes)
console.log(snap.lines); // Array of lines
console.log(snap.alive); // Process still running?

// Get SVG rendering (for visual analysis)
const svgSnap = await term.snapshot({ format: "svg" });
console.log(svgSnap.svg); // SVG string

// Resize
await term.resize(80, 24);

// Clear buffer
await term.clear();

// Wait for text to appear
const found = await term.waitForText("Ready", { timeout: 5000 });

// Wait for process to exit
const exitCode = await term.waitForExit({ timeout: 10000 });

Special Keys

Use term.key() with these names:

Example: Debug a TUI App

cd dev-terminal && npx tsx <<'EOF'
import { connect, sleep } from "./src/client.js";

const client = await connect();

// Start the TUI
const term = await client.terminal("claude-monitor", {
  command: "../.venv/bin/python",
  args: ["-m", "claude_monitor"],
  cols: 120,
  rows: 40,
  cwd: "..",
});

// Wait for it to render
await sleep(2000);

// Capture screen
const snap = await term.snapshot();
console.log("=== SCREEN OUTPUT ===");
console.log(snap.text);
console.log("=== ALIVE:", snap.alive, "===");

client.disconnect();
EOF

Example: Interactive Session

# Script 1: Start app
cd dev-terminal && npx tsx <<'EOF'
import { connect, sleep } from "./src/client.js";
const client = await connect();
const term = await client.terminal("my-tui", {
  command: "htop",
});
await sleep(1000);
const snap = await term.snapshot();
console.log(snap.text);
client.disconnect();
EOF

# Script 2: Send keys (terminal persists!)
cd dev-terminal && npx tsx <<'EOF'
import { connect, sleep } from "./src/client.js";
const client = await connect();
const term = await client.terminal("my-tui"); // Reconnect to existing
await term.key("down");
await term.key("down");
await sleep(500);
const snap = await term.snapshot();
console.log(snap.text);
client.disconnect();
EOF

# Script 3: Quit
cd dev-terminal && npx tsx <<'EOF'
import { connect } from "./src/client.js";
const client = await connect();
const term = await client.terminal("my-tui");
await term.write("q");
client.disconnect();
EOF

Error Recovery

If something goes wrong, check the terminal state:

cd dev-terminal && npx tsx <<'EOF'
import { connect } from "./src/client.js";

const client = await connect();

// List all terminals
const terminals = await client.list();
console.log("Active terminals:", terminals);

// Check specific terminal
if (terminals.includes("my-app")) {
  const term = await client.terminal("my-app");
  const snap = await term.snapshot();
  console.log("Alive:", snap.alive);
  console.log("Exit code:", snap.exitCode);
  console.log("Last output:", snap.lines.slice(-20).join("\n"));
}

client.disconnect();
EOF

Tips

• TUI apps need time: Use sleep() after starting to let them render
• Check alive status: TUI might crash – check snap.alive
• Clear for fresh state: Use term.clear() before important snapshots
• Large output: snap.lines gives the last ~120 lines (3x terminal height)