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MRC System

MRC stands for Manifest Request Code - a short-lived token Steam hands out that lets you download a specific manifest file for a depotid.

BetterSteamTools keeps a shared archive of Steam depot manifests. If a game you want is already in that archive, it downloads normally. If it isn't, someone who owns that game can contribute it - automatically, in the background, without sharing anything about their library.

This page explains what that means for you, what your PC actually sends, and how to turn it off.

Why downloads need this at all​

To download a depot, Steam wants an MRC. Three things about it matter:

  • It's tied to one exact depot and one exact version
  • It expires within about 5 minutes.
  • Only an account that actually owns the game can generate one (following the exploit getting patched).

But there's a shortcut. If the manifest file is already sitting in your <Steam>/depotcache folder, Steam just reads it from disk and never asks for a code at all. That's the whole idea: put the manifest there first, and the download works like any normal game.

When you download a game​

Before Steam gets a chance to ask for a code, BetterSteamTools tries to fetch the manifest from the archive and drop it into depotcache.

"manifests not ready" is not a broken install

It means that exact version isn't in the archive yet. It's now on the list for donors to supply - try again later!

When you donate​

This is the other half, and it only involves games you already own.

Steam tells the client what depot it owns so no extra requests are needed. You also donate for free just by playing: when you download a game you own normally, Steam mints a code as part of that download, and BetterSteamTools passes it along. That costs no extra requests!

What leaves your PC — and what doesn't​

What gets sent to LuaTools servers anonymously:

  • Depot and manifest IDs that were already on the wanted list and that you own.
  • The short-lived MRC for those. This code is the same for everyone so this does not identify you. Thank you steam!

A few more things worth knowing:

  • Nothing extra is asked of Steam to work out what you own. That comes from the license list Steam already sends client PC when you sign in. It's read as it arrives.
  • Codes are never stored. They're used immediately and thrown away. They'd be worthless within minutes anyway.
  • The manifest itself isn't private. It's a file listing that Steam's own CDN hands to anyone holding a valid code. A manifest CANNOT change (for that specific manifest id anyway, depots can have new "latest" manifests.)

Turning it off​

Add this to opensteamtool.toml in your Steam folder (please consider not though, help out the community and don't be a leech!):

[donate]
enabled = false