Factorio Forums

Productivity modules claim to only work when producing intermediates, but this recipe seems to be the one exception in the game (excluding science packs and fluoroketone cooling for reasons.)

Thanks for the report however this is working correctly.

I think stone bricks in electric furnaces also allow productivity modules, don't they?

For the public record, this triggered discussions in the Factorio discord to which I will link instead of summarize: https://discord.com/channels/1396775903 ... 4754672830

The "can only be used on intermediate products" message is simply a helpful hint to the player. There's no hard rule that's enforcing that. In fact, the actual rule is:

1. The recipe must have productivity in its allowed-effects
2. The recipe must have the modules module category in its allowed-module-categories
3. The crafting machine must have productivity in its allowed-effects

If any of those are not true, then the module can't be used on the recipe and you get either the recipe defined error for why it's not allowed, or if the recipe has not defined any specific errors you get the generic fallback error of "item-limitation.productivity-effect" which for English is defined as: "productivity-effect=Productivity module can only be used on intermediate products."

If you try to use a quality module and it fails, the generic message for that is "item-limitation.quality-effect" which is defined as "quality-effect=Quality modules cannot be used on this recipe."

We could always make the productivity one say something similar like:

"Productivity modules cannot be used on this recipe" - but the hint at intermediate products has been deemed more useful.

My interest was in the design of Factorio rather than how the engine implements that design. However thanks for confirming OP is not a bug (by which I mean a mistake in the implementation of the design).

It is interesting that it is a single exception among all (non-furnace, non-recycling) recipes. We gave some conjectures in Discord about why this would be.

thesixthroc wrote: Fri May 09, 2025 1:30 pmIt is interesting that it is a single exception among all (non-furnace, non-recycling) recipes. We gave some conjectures in Discord about why this would be.

Is it interesting or a mystery, or even a Unique recipe? I think that Concrete is an Intermediate product that happens to be able to be placed as a Tile, so it makes perfect sense that Productivity modules work.

• The primary ingredients for Concrete are Iron - an Intermediate Product itself
• and Bricks which are definitely an "Intermediate Product", since Productivity Modules work in Furnaces for Stone
• The Wiki plainly shows the "Consumed By" for Concrete has multiple End uses which do not support Productivity Modules: high-end Buildings, and purely-Decorative Items Hazard/Refined Concrete

If anything, I would say that the issue is that Concrete (and Bricks) are listed in the Logistics Tab rather than the Intermediates tab. This is presumably because of the internal usage of the "Tile" prototype and inheritance-based categorization of Recipes; whereas the Crafting Chain system's "Intermediate" classification is a side-effect of the Recipes' Productivity-eligibility flags. Also that's where everybody looks for it.