Why

AI coding agents (Claude Code, Codex, etc.) typically run one command at a time. Forge gives them persistent terminals — run your React frontend, Java API, and Postgres migrations in parallel, monitor all three, and only read what changed. Full-stack work without the bottleneck.

Works with any MCP-compatible client — Claude Code, Codex, or your own agent.

Key differentiators:

• Real PTY via node-pty (same lib as VS Code terminal) — interactive programs, colors, TUI apps all work
• Incremental reads — ring buffer with per-consumer cursors means each read_terminal only returns NEW output, saving context window tokens
• Clean screen reads — @xterm/headless renders the terminal server-side, so read_screen returns exactly what a human would see (no ANSI escape codes)
• Multi-agent orchestration — spawn Claude and Codex sub-agents, session groups, output multiplexing, event subscriptions, and templates for managing multiple concurrent sessions
• Web dashboard — real-time Preact-based browser UI to watch what your agents are doing across all terminals, browse past chat sessions, and monitor activity
• Zero config — single npx command or HTTP MCP endpoint

Quick Start

1. Add to Your Agent

# Basic (stdio)
claude mcp add forge -- npx forge-terminal-mcp

# With web dashboard
claude mcp add forge -- npx forge-terminal-mcp --dashboard --port 3141

Or add to ~/.claude/settings.json:

{
  "mcpServers": {
    "forge": {
      "command": "npx",
      "args": ["forge-terminal-mcp", "--dashboard", "--port", "3141"]
    }
  }
}

# Add Forge as HTTP MCP server
codex mcp add forge --url http://127.0.0.1:3141/mcp

# Verify
codex mcp list
codex mcp get forge

Codex stores this in ~/.codex/config.toml:

[mcp_servers.forge]
url = "http://127.0.0.1:3141/mcp"

Start the daemon (choose one launch mode), then point any MCP client at the HTTP endpoint:

# If forge is on PATH (global install or npm link)
forge start -d

# From this repo (local clone)
node dist/cli.js start -d

# Without install (published package)
npx forge-terminal-mcp start -d

{
  "mcpServers": {
    "forge": {
      "type": "http",
      "url": "http://127.0.0.1:3141/mcp"
    }
  }
}

Restart your agent and Forge tools are available.

Important: Codex and Claude Code load MCP servers at process start. If you add/remove servers, restart the current agent session.

2. Smoke Test (60s)

# Codex MCP registration
codex mcp list
codex mcp get forge

# Forge daemon status
node dist/cli.js status

Expected:

• codex mcp list shows forge as enabled
• node dist/cli.js status reports running and http://127.0.0.1:3141

Troubleshooting

| Symptom | Fix | |---------|-----| | forge: command not found | Use node dist/cli.js ... from the repo root, or npx forge-terminal-mcp .... | | No MCP servers configured yet in Codex | Run codex mcp add forge --url http://127.0.0.1:3141/mcp, then restart Codex. | | listen EPERM ... 127.0.0.1:3141 | Run Forge in an environment that allows local port binding, or use a different port with --port and update the MCP URL to match. | | A message appears typed but agent does not answer | The input may be queued; press Enter (or use submit=true when writing programmatically). | | MCP server is configured but tools do not appear | Restart the current agent session so MCP servers reload. |

3. Use It

Your agent now has access to 23 tools across 7 categories:

Session Lifecycle

create_terminal      → Spawn a PTY session with optional name, tags, buffer size
create_from_template → Spawn from a built-in template (shell, next-dev, vite-dev, etc.)
spawn_claude         → Launch a Claude Code sub-agent in a dedicated session
spawn_codex          → Launch a Codex sub-agent in a dedicated session
close_terminal       → Kill a session and free resources
close_group          → Close all sessions matching a tag
list_terminals       → List sessions, optionally filtered by tag
list_templates       → Show available session templates

I/O

write_terminal       → Send input (appends newline by default)
read_terminal        → Read NEW output since last read (incremental)
read_screen          → Get rendered viewport as clean text (no ANSI)
read_multiple        → Batch read from up to 20 sessions at once
send_control         → Send Ctrl+C, arrow keys, Tab, Enter, etc.
resize_terminal      → Change terminal dimensions

Search & Wait

grep_terminal        → Regex search across a session's output buffer
wait_for             → Block until output matches a pattern or process exits

Execution

run_command          → Run a command to completion, return output, auto-cleanup

Events

subscribe_events     → Get notified when a session exits or matches a pattern
unsubscribe_events   → Cancel an event subscription

Agent Delegation

delegate_task        → Delegate a task to another agent — oneshot or interactive multi-turn

Ops

health_check         → Server version, uptime, session count, memory usage
get_session_history  → Tool call history for agent sessions
clear_history        → Clear persisted stale session entries

Example Conversations

You: Start a Next.js dev server and run the test suite in parallel

Agent: (uses create_from_template with "next-dev", wait_for "Ready", then creates a second session for npm test, uses read_multiple to poll both)

You: Spin up 3 sub-agents to research different parts of the codebase

Agent: (uses spawn_claude three times with tag "research", monitors with list_terminals filtered by tag, cleans up with close_group)

You: Build and test, just give me the result

Agent: (uses run_command with npm run build && npm test — creates terminal, waits for exit, returns output, auto-cleans up)

Best Practices

run_command vs create_terminal

Use run_command when you want a result and don't need the session afterwards:

• Build steps (npm run build, cargo build)
• Test runs (npm test, pytest)
• Install commands (npm install, pip install)
• One-off scripts that exit cleanly

Use create_terminal when you need an ongoing session:

• Dev servers (npm run dev, vite, next dev)
• Watchers (npm run watch, tsc --watch)
• REPLs or interactive processes
• Long-running processes you'll poll with read_terminal

# Good — build is a one-shot task
run_command({ command: "npm run build && npm test" })

# Good — dev server needs to stay alive
create_terminal({ command: "npm run dev", name: "dev-server" })
wait_for({ id, pattern: "ready on" })

waitForExit vs pattern matching

Use pattern matching (default) when the process stays alive after printing the signal:

wait_for({ id, pattern: "Server running on port 3000" })
# returns as soon as the line appears — process keeps running

Use waitForExit: true when the process exits naturally and you want all output:

wait_for({ id, pattern: ".", waitForExit: true })
# waits for the process to finish, returns everything

fromSession for sub-agents

When spawning a sub-agent to work on the same project, use fromSession instead of hardcoding paths:

# Instead of this (brittle):
spawn_claude({ prompt: "...", cwd: "/Users/me/projects/my-app" })

# Do this (inherits cwd from current session):
spawn_claude({ prompt: "...", fromSession: currentSessionId })

This ensures the sub-agent works in the correct directory even when Forge is used across different machines or worktrees.

Worktrees for parallel agents

When running multiple agents on the same codebase, use worktree: true to isolate changes:

spawn_claude({ prompt: "Add auth", worktree: true, branch: "feature/auth" })
spawn_claude({ prompt: "Add payments", worktree: true, branch: "feature/payments" })
# Both agents work in parallel without stepping on each other

Tools Reference

create_terminal

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | command | string | User's $SHELL | Command to run | | args | string[] | [] | Command arguments | | cwd | string | Process cwd | Working directory | | env | object | {} | Additional env vars (merged with process env) | | cols | number | 120 | Terminal width | | rows | number | 24 | Terminal height | | name | string | — | Human-readable session name | | tags | string[] | — | Tags for filtering/grouping (max 10) | | bufferSize | number | Server default | Ring buffer size in bytes (1 KB – 10 MB) |

Returns session info including the id used by all other tools.

create_from_template

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | template | string | required | Template name (see list_templates) | | cwd | string | — | Working directory override | | env | object | — | Additional env vars | | name | string | Template name | Session name override |

Built-in templates:

| Template | Command | Tags | Wait For | |----------|---------|------|----------| | shell | $SHELL | shell | — | | next-dev | npx next dev | dev-server, next | "Ready" | | vite-dev | npx vite | dev-server, vite | "Local:" | | docker-compose | docker compose up | docker | — | | npm-test | npm test | test | — | | npm-test-watch | npm run test:watch | test, watch | — |

Templates with waitFor automatically block until the pattern appears (30s timeout).

spawn_claude

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | prompt | string | required | Prompt to send to Claude | | cwd | string | — | Working directory (explicit path) | | fromSession | string | — | Copy cwd from an existing session ID (alternative to setting cwd manually) | | model | string | — | Model (e.g., "sonnet", "opus") | | name | string | Auto from prompt | Session name | | tags | string[] | ["claude-agent"] | Tags (claude-agent always included) | | maxBudget | number | — | Max budget in USD | | bufferSize | number | Server default | Ring buffer size | | worktree | boolean | false | Create a git worktree (isolates file changes) | | branch | string | — | Branch name for worktree (required when worktree: true) | | oneShot | boolean | false | Run in --print mode (process prompt and exit) |

run_command

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | command | string | required | Command to run (supports && chaining) | | cwd | string | — | Working directory | | timeout | number | 300000 | Timeout in ms (max 5 minutes) |

Creates a terminal, waits for the process to exit, returns all output, and auto-cleans up the session. Ideal for build/test/install commands.

write_terminal

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID | | input | string | required | Text to send | | newline | boolean | true | Append \n after input |

read_terminal

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID |

Returns { status, data, bytes, droppedBytes? }. Only returns output produced since the last read. If droppedBytes > 0, some output was lost because the ring buffer wrapped.

read_screen

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID |

Returns the current terminal viewport as plain text — rendered through a headless xterm instance. No ANSI codes. Useful for TUI apps like htop, vim, or interactive prompts.

read_multiple

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | ids | string[] | required | Session IDs (1–20) | | mode | string | "incremental" | "incremental" or "screen" |

Returns a JSON array with per-session results. Sessions that error (e.g., not found) include an inline error field — the tool never fails as a whole, so partial results are always returned.

grep_terminal

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID | | pattern | string | required | Regex pattern | | context | number | 0 | Lines of context around each match (0–10) |

Returns { matches: [{ lineNumber, text, context? }], totalMatches }.

wait_for

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID | | pattern | string | — | Regex pattern to wait for | | timeout | number | 30000 | Timeout in ms (100–300000) | | waitForExit | boolean | false | Wait for process to exit instead of pattern match |

Checks the existing buffer first (instant match if pattern already appeared), then watches new output. Returns { matched, data?, reason?, elapsed }.

subscribe_events

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID | | events | string[] | required | ["exit"] and/or ["pattern_match"] | | pattern | string | — | Regex (required if pattern_match in events) |

Notifications are delivered as MCP logging messages with JSON payloads. Pattern match subscriptions auto-unsubscribe after the first match.

unsubscribe_events

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | subscriptionId | string | required | Subscription ID from subscribe_events |

list_terminals

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | tag | string | — | Filter sessions by tag |

Returns all sessions with id, pid, command, cwd, status, cols, rows, createdAt, lastActivityAt, name, tags.

close_terminal

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID |

close_group

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | tag | string | required | Tag to match |

Closes all active sessions with the matching tag. Returns the count closed.

send_control

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID | | key | string | required | Control key name |

Available keys: ctrl+c, ctrl+d, ctrl+z, ctrl+\, ctrl+l, ctrl+a, ctrl+e, ctrl+k, ctrl+u, ctrl+w, ctrl+r, ctrl+p, ctrl+n, up, down, right, left, home, end, tab, enter, escape, backspace, delete, pageup, pagedown

resize_terminal

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID | | cols | number | required | New width (1–500) | | rows | number | required | New height (1–200) |

health_check

No parameters. Returns { version, uptime, sessions: { active, max }, memory: { rss, heapUsed, heapTotal } }.

get_session_history

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | id | string | required | Session ID |

Returns timestamped tool call history for agent sessions (Claude, Codex).

clear_history

No parameters. Clears persisted stale session entries from previous server runs.

MCP Resources

Sessions are also exposed as MCP resources at terminal://sessions/{sessionId}, returning session metadata and rendered screen content. The resource list updates automatically when sessions are created or closed.

Web Dashboard

Enable the real-time web dashboard to monitor all terminals from your browser:

{
  "mcpServers": {
    "forge": {
      "command": "npx",
      "args": ["forge-terminal-mcp", "--dashboard", "--port", "3141"]
    }
  }
}

Open http://localhost:3141 to see:

• Live terminal sessions with real-time output via WebSocket
• Session grouping — terminals organized by working directory
• Activity log — tool calls and events for agent sessions
• Status bar — working directory, session ID, running/exited status
• Chat history browser — search, browse, and continue past Claude Code and Codex conversations grouped by project
• Session management — create, close, and switch between terminals
• Auto-follow mode — automatically switch to newly created sessions
• Memory monitoring — per-session and total RAM usage

If --auth-token is enabled, open the dashboard with ?token=YOUR_TOKEN so browser API/WebSocket calls are authorized.

The dashboard is built with Preact + htm + Preact Signals, loaded from CDN with zero build step. All UI code is bundled as string constants inside the server binary.

Desktop App (macOS)

Note: The pre-built macOS app is currently unavailable for general download. macOS requires apps to be code-signed with an Apple Developer certificate ($99/year) before they can be opened without security warnings. We're working on getting this set up — in the meantime, you can run the desktop app from source (see below) or use the CLI via npx forge-terminal-mcp.

Forge includes an Electron-based desktop app for macOS with native window management, system tray, and notifications.

Running in Development

npm run build                    # Build forge core
cd desktop && npm install        # Install Electron deps
npx @electron/rebuild            # Rebuild node-pty for Electron
npm run dev                      # Launch the desktop app

Or from the repo root: npm run desktop:dev

Features

• Native macOS title bar with traffic light integration
• System tray with session count, new terminal, start-at-login toggle
• Close-to-tray (app keeps running when window closed)
• Native notifications on session created/exited
• Window state persistence across restarts
• Auto-detects existing CLI daemon — connects to it or starts in-process
• Automatic updates via GitHub Releases (downloads silently, installs on restart)
• Security hardened: sandboxed renderer, navigation lock, CSP, permission deny-all

Packaging

cd desktop
npm run package          # Build DMG + ZIP

Produces a signed Forge.app in desktop/release/. Requires Apple Developer certificate for notarization (see desktop/forge.entitlements.plist).

Configuration

All settings follow the precedence: CLI flag > environment variable > default.

| Flag | Env Var | Default | Description | |------|---------|---------|-------------| | --max-sessions | FORGE_MAX_SESSIONS | 10 | Max concurrent PTY sessions | | --idle-timeout | FORGE_IDLE_TIMEOUT | 1800000 | Session idle timeout in ms (30 min) | | --buffer-size | FORGE_BUFFER_SIZE | 1048576 | Ring buffer size per session (1 MB) | | --shell | SHELL | /bin/bash | Default shell for create_terminal | | --claude-path | FORGE_CLAUDE_PATH | claude | Path to Claude CLI binary | | --auth-token | FORGE_AUTH_TOKEN | unset | Require Bearer token for /mcp, /api, and /ws | | --dashboard | FORGE_DASHBOARD | off | Enable web dashboard | | --port | FORGE_DASHBOARD_PORT | 3141 | Dashboard port | | --verbose | — | off | Enable debug logging to stderr |

Example with custom config:

{
  "mcpServers": {
    "forge": {
      "command": "npx",
      "args": ["forge-terminal-mcp", "--max-sessions", "20", "--idle-timeout", "3600000", "--dashboard"]
    }
  }
}

Architecture

MCP Client   <--stdio-->  MCP Server (23 tools + 1 resource)
(Claude Code,    or
 Codex, etc) <--HTTP--->
                              |
                         SessionManager
                         (lifecycle, groups, persistence)
                              |
                    +---------+---------+
                    v         v         v
               TerminalSession    TerminalSession    ...
               +---------------+
               |   node-pty     |  <-- real PTY (colors, signals, TUI)
               |  RingBuffer    |  <-- 1 MB circular, per-consumer cursors
               | @xterm/headless|  <-- server-side rendering
               +---------------+
                              |
              +---------------+---------------+
              v               v               v
         MCP Client      Dashboard WS    Event Subs
         (incremental)   (live stream)   (notifications)

• Single Node.js process — MCP server communicates over stdio (JSON-RPC) or HTTP (streamable)
• All logging to stderr — stdout is reserved for the MCP protocol
• Ring buffer per session — 1 MB circular buffer with cursor-based reads. When the buffer fills, old data is overwritten and droppedBytes tells the consumer how much was lost
• Headless xterm per session — full terminal emulation server-side. read_screen returns the rendered viewport, correctly handling cursor positioning, alternate screen, line wrapping
• Idle timeout — sessions auto-close after 30 minutes of inactivity (configurable)
• Session persistence — session metadata saved to ~/.forge/sessions.json, reloaded as stale entries on restart
• Event system — subscribe to session exit or pattern match events, delivered as MCP logging messages
• Agent env stripping — spawned terminals have agent-specific env vars (e.g., CLAUDECODE) removed to prevent nesting errors

Development

git clone https://github.com/ferodrigop/forge-terminal-mcp.git
cd forge-terminal-mcp
npm install
npm run build       # Compile with tsup
npm test            # 161 tests (unit + integration)
npm run typecheck   # TypeScript strict mode
npm run lint        # ESLint
npm run dev         # Watch mode

Project Structure

src/
  cli.ts                        # Entry point, arg parsing, stdio transport
  server.ts                     # McpServer + 22 tool registrations + resources
  core/
    types.ts                    # ForgeConfig, SessionInfo, defaults
    ring-buffer.ts              # Circular buffer with multi-consumer cursors
    terminal-session.ts         # PTY + headless xterm + ring buffer
    session-manager.ts          # CRUD, max sessions, groups, persistence
    state-store.ts              # ~/.forge/sessions.json persistence
    templates.ts                # Built-in session templates
    claude-chats.ts             # Claude Code chat session discovery
    command-history.ts          # Tool call history tracking
  dashboard/
    dashboard-server.ts         # HTTP + WebSocket + MCP transport server
    dashboard-html.ts           # HTML assembler (imports frontend parts)
    ws-handler.ts               # WebSocket message handling
    frontend/
      styles.ts                 # CSS styles (Tokyo Night theme)
      state.ts                  # Preact Signals + WebSocket + chat API
      utils.ts                  # timeAgo, formatSize, formatToolBlock
      app.ts                    # Root App component + JS concatenation
      assets.ts                 # Base64-embedded favicon + logo
      components/
        sidebar.ts              # Session list, chat browser, connection status
        terminal-view.ts        # XTerm container, activity log, status bar
        chat-view.ts            # Chat message viewer with bubbles
        modals.ts               # New terminal + delete chat modals
  utils/
    logger.ts                   # stderr-only JSON logger
    config.ts                   # CLI flags > env vars > defaults
    control-chars.ts            # Named key -> escape sequence map
    daemon.ts                   # Daemon lifecycle (PID, port, lock files)
desktop/
  main/
    index.ts                    # Electron main process entry
    daemon.ts                   # Forge server lifecycle (start/detect existing)
    window.ts                   # BrowserWindow + state persistence
    preload.ts                  # Context bridge (forgeDesktop API)
    tray.ts                     # System tray + context menu
    menu.ts                     # macOS application menu
    notifications.ts            # Native notification bridge
    auto-launch.ts              # Login item registration
    html-server.ts              # Lightweight HTTP server for desktop HTML
    daemon-bridge.ts            # WebSocket relay to existing daemon
    updater.ts                  # Auto-update via GitHub Releases
  electron-builder.yml          # Build config (DMG, universal binary)
  forge.entitlements.plist      # macOS entitlements
test/
  unit/                         # ring-buffer, config, control-chars, state-store, templates
  integration/                  # terminal-session, session-manager, mcp-tools E2E

Test Coverage

| Suite | Tests | Covers | |-------|-------|--------| | Ring Buffer | 13 | Circular writes, multi-consumer, wrap-around, dropped bytes | | Config | 10 | CLI parsing, env vars, defaults, precedence, codex path | | Control Chars | 6 | Key resolution, case insensitivity, unknown keys | | State Store | 4 | Load/save round-trip, corruption handling | | Templates | 3 | Lookup, unknown template, list all | | Stream JSON Parser | 11 | Claude event parsing, tool use extraction | | Terminal Session | 8 | PTY spawn, read/write, screen render, resize, exit | | Session Manager | 7 | CRUD, max limit, close all, stale entries | | MCP Tools E2E | 51 | All 23 tools end-to-end via MCP client | | Forge 0.7 Features | 28 | Codex spawn, worktree, dashboard API, chat history | | Command History | 6 | Event tracking, retrieval, cleanup | | Claude Chats | 14 | Session discovery, message parsing, search | | Total | 161 | |

Requirements

• Node.js >= 18
• macOS, Linux, or Windows (anywhere node-pty builds)

License

MIT