GABS - Game Agent Bridge Server

Compatible with GABP v1.1 on wire major gabp/1.

GABS lets MCP-capable AI tools start games, check status, and call tools exposed by GABP-compatible game integrations.

If you are installing GABS from a release archive, start with Quick Start below. If you want the full copy-paste setup guide, read the AI Client Setup Guide.

Why GABS?

GABS is aimed at developers who want a practical way to connect local AI tools to real games.

• Configure games once with gabs games add
• Keep everything local by default
• Work with Claude Desktop, Codex CLI, and other MCP clients
• Support direct executables, managed Steam games, Epic App IDs, and custom commands
• Mirror game-specific tools into MCP when the bridge connects

Quick Start

1. Download and verify the binary

Download the latest release bundle for your system from GitHub Releases.

Available archives are named like:

• Windows x64: gabs-<version>-windows-amd64.zip
• macOS Apple Silicon: gabs-<version>-darwin-arm64.zip
• macOS Intel: gabs-<version>-darwin-amd64.zip
• Linux x64: gabs-<version>-linux-amd64.zip
• Linux ARM64: gabs-<version>-linux-arm64.zip

Each archive contains:

• the gabs binary (gabs.exe on Windows)
• README.md
• the full docs/ folder
• example-config.json
• LICENSE

After unzipping:

Windows

.\gabs.exe version

macOS / Linux

chmod +x gabs
./gabs version

2. Add a game

# Interactive setup
gabs games add factory

# See saved game IDs
gabs games list

# Show one game's saved config
gabs games show factory

The setup is interactive. In most cases you only need to answer:

• Game name: a label you recognize
• Launch mode: direct path, managed Steam, Epic App ID, or custom command
• Target: the executable path or store App ID
• Stop process name: the real game process name used by games.stop and games.kill

For SteamManaged, GABS resolves the Steam app to the installed executable and starts Steam if needed. For launcher URL modes such as SteamAppId and EpicAppId, stopProcessName is required. Example values: GameName.exe, AdventureGame, or java.

3. Add GABS to your AI client

Paste one of these into your AI client's MCP config.

Claude Desktop:

{
  "mcpServers": {
    "gabs": {
      "command": "/path/to/gabs",
      "args": ["server"]
    }
  }
}

Codex CLI:

[mcp_servers.gabs]
command = "/absolute/path/to/gabs"
args = ["server"]

Generic MCP client:

{
  "command": "/absolute/path/to/gabs",
  "args": ["server"]
}

If your client uses strict OpenAI-style tool naming, enable toolNormalization in ~/.gabs/config.json. See OpenAI Tool Normalization. If your client disconnects after tools/list because it rejects a public tool's outputSchema fields, set stripOutputSchema to true. See the Configuration Guide. Mirrored game tools are discovered through games_tool_names and are not advertised in the public tools/list response. If a game or bridge starts slowly, tune the total background connection budget with the timeouts.startup section described in the Configuration Guide. games_start still returns after a bounded initial wait so MCP clients do not time out while the game keeps loading.

4. Try these prompts

• "List my games"
• "Start AdventureGame"
• "Show the status of all games"
• "Stop FactorySim"

If you want a download-to-working walkthrough, use the AI Client Setup Guide.

Common Setup Notes

• Steam/Epic stopping: use the real game process name, not the launcher name.
• Steam bridge games: prefer SteamManaged launch. It resolves the Steam app manifest to the installed game executable, starts Steam if needed, and launches the real game process with GABP environment variables. Use gabs games doctor <id> to inspect a config and gabs games repair <id> to convert an older SteamAppId launcher URL config.
• More than one AI session: that is fine. GABS coordinates ownership per game with a short active-owner lease. You can hop between live sessions: games_connect takes over naturally after the previous session goes idle, while active game-bound calls are still protected from competing sessions.
• Game bridge cannot find GABP configuration: the game-side bridge should read GABP_SERVER_PORT, GABP_TOKEN, and GABS_GAME_ID from its process environment. The bridge.json file is GABS' endpoint cache/debug artifact, not runtime input for game-side bridge code.
• Stopped game still has bridge.json: this is normal. Treat it as an endpoint cache/debug artifact, not a recovery target.
• Start says the endpoint cache port is already in use: use games_connect if an existing game-side bridge owns that endpoint. Use games_start with resetEndpoint: true only after confirming the cache should be rotated for a new process.
• Confusing bridge state: start with games_status. It compares the runtime state and process environment where the OS allows it. If a Steam launcher URL config reused old GABP environment, run gabs games repair <id> to switch to managed Steam launch.

How It Works

Most users only need this mental model:

• Your AI client starts gabs server
• GABS starts or attaches to your game
• If the game-side bridge speaks GABP, GABS mirrors that bridge's tools into MCP

Architecture details matter mainly if you are writing a game-side bridge or debugging a bridge issue.

AI Agent ← MCP → GABS ← GABP Client → GABP Server (Game Bridge) ← Game API → Game

In the GABP layer, your game-side bridge is the server and GABS is the client.

Common MCP Tools

Most users only need a few tools at first. Release builds expose strict-safe MCP tool names by default because some clients reject dots in tool names:

• games_list - List configured game IDs
• games_show - Show one saved game config
• games_start - Start a game
• games_stop - Stop a game gracefully
• games_kill - Force stop a game
• games_status - Check if a game is running
• games_connect - Reconnect to a running game's game-side bridge
• games_tool_names - List mirrored game-specific tools after a bridge connects
• games_tool_detail - Show the schema for one mirrored tool
• games_call_tool - Call a connected game tool through the stable core surface

The older dotted names such as games.list and games.call_tool remain accepted as call aliases, but tools/list advertises strict-safe names unless you explicitly disable normalization in config.

For the full MCP surface and advanced behavior, see the AI Integration Guide.

Game-Specific Tools from Bridges

When a GABP-compatible bridge connects, GABS mirrors the bridge's canonical slash-delimited GABP tool names into strict-safe names such as factory_inventory_get or adventure_crafting_build. The public tools/list response stays core-only so clients do not churn on large game-specific tool sets. Use games_tool_names for discovery, games_tool_detail for one schema, and games_call_tool for the actual call. Direct mirrored MCP tools may still be callable when you already know the name, but agents should not depend on dynamic tools/list refreshes.

The usual discovery flow is:

AI: "Reconnect to AdventureGame and show me its game-specific tools"
GABS: games_connect {"gameId": "adventure"}
GABS: games_tool_names {"gameId": "adventure", "brief": true}
GABS: games_tool_detail {"tool": "adventure_crafting_build"}

Most users can ignore attention gating, resource mirroring, and protocol details until they need them. Those topics are covered in the dedicated docs.

Documentation

• AI Client Setup Guide - Install a release bundle and connect Claude Desktop, Codex CLI, or generic MCP clients
• Configuration Guide - Detailed setup for different game types and tool normalization
• AI Integration Guide - Connect GABS to different AI tools and deployment scenarios
• GABP Bridge Development Guide - Add GABP support to your game integrations
• Advanced Usage Guide - Multiple instances, HTTP mode, scripting, and more
• Deployment Guide - Production deployments and cloud setups
• OpenAI Tool Normalization - Configure tool name compatibility for OpenAI API
• Dynamic Tools Guide - How AI agents handle expanding tool sets
• AI Dynamic Tools FAQ - Common questions about dynamic tool discovery

For Bridge Developers

Want your game to work with GABS? Add GABP support to your game-side bridge:

1. Read GABP configuration from environment variables when your game starts:
   • GABS_GAME_ID - Your game's identifier
   • GABP_SERVER_PORT - Port your game-side bridge should listen on
   • GABP_TOKEN - Authentication token for GABS connections The bridge.json file is GABS' endpoint cache/debug artifact. Do not read it as game-side runtime configuration.
2. Start a local GABP server to listen for GABS connections (your game-side bridge = server, GABS = client)
3. Implement the current GABP runtime methods (session/hello, tools/list, tools/call) or use the official gabp-runtime library so your schemas match what GABS expects
   • For GABP v1.1 bridges, advertise optional attention support through capabilities before exposing attention/current, attention/ack, and the attention lifecycle channels
4. Expose game features as tools, resources, and events using canonical GABP tool names such as inventory/get or core/ping

See the GABP Bridge Development Guide for complete examples in C#, Java, and Python.

Build from Source

Requirements: Go 1.22+

# Simple build
go build ./cmd/gabs

# Build with version information (recommended)
make build

# Build with custom version
go build -ldflags "-X github.com/pardeike/gabs/internal/version.Version=vX.Y.Z" ./cmd/gabs

Contributing & Support

• Issues & Ideas: GitHub Issues
• GABP Protocol: GABP Repository
• Example Configuration: See example-config.json for sample configurations

License

MIT License - see LICENSE for details.

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GABS makes AI-game interaction simple. Configure once, control naturally.