DLL Injection

OpenSteamTool supports optional DLL injection into game processes. This is configured through the [inject] section of opensteamtool.toml.

Configuration

[inject]
enabled = true
library_x64 = "OpenSteamTool.GameHook.x64.dll"
library_x86 = "OpenSteamTool.GameHook.x86.dll"

Key	Type	Default	Description
enabled	boolean	false	Enable game-process injection
library_x64	string	—	Path to the x64 library to inject
library_x86	string	—	Path to the x86 library to inject

Path Resolution

Paths can be:

• Absolute paths — e.g. C:\Tools\myhook_x64.dll
• Relative paths — resolved from the Steam root directory (where steam.exe lives)

Architecture Matching

The injection system automatically matches the target process architecture:

• x64 games get the library_x64 DLL
• x86 (32-bit) games get the library_x86 DLL

Injection Behavior

• Injection is performed once per detected game process
• The DLL is injected when the game process starts
• Only one injection per process lifetime

Use Cases

Possible uses for game-process injection include:

• Custom rendering overlays
• Input hooks
• Performance monitoring
• Game-specific patches
• Debugging tools

Security Considerations

• Only inject DLLs from sources you trust
• Verify the integrity of any DLL you plan to inject
• Some anti-cheat systems may flag injected DLLs
• Game-process injection may violate terms of service for some games

Example: Minimal Setup

[inject]
enabled = true
library_x64 = "OpenSteamTool.GameHook.x64.dll"
library_x86 = "OpenSteamTool.GameHook.x86.dll"

Place the DLL files in the Steam root directory alongside opensteamtool.toml.

Upcoming Features

A new [[inject]] array syntax is in development (PR #146 — Draft) that supports injecting arbitrary DLLs with per-rule command-line conditions. This also enables the OnlineFix companion DLL for games whose matchmaking runs outside Steam.

See the Upcoming Injection Rules page for details.