Can you get the benefits from tool proficiency to make ability checks, even if you don't have/own the tool?

Question

I'm sorry if this has been covered elsewhere, but all the related questions I found asked the opposite scenario (using the tool you own without having proficiency), and the PHB is pretty poor in explaining how these tools work.

I'm gonna use as an example the Cartographer's tool:

Using cartographer's tools, you can create accurate maps to make travel easier for yourself and those who come after you. These maps can range from large-scale depictions of mountain ranges to diagrams that show the layout of a dungeon level.

Components. Cartographer's tools consist of a quill, ink, parchment, a pair of compasses, calipers, and a ruler.

The way some of the skills benefits are described seems to imply that you would get the bonus from the proficiency to your ability checks, even if you don't have the tools in your equipment, because it would be granted by the experience/knowledge you acquired from using them, and not by something the components themselves allow you to do, for instance:

Survival. Your understanding of geography makes it easier to find paths to civilization, to predict areas where villages or towns might be found, and to avoid becoming lost. You have studied so many maps that common patterns, such as how trade routes evolve and where settlements arise in relation to geographic locations, are familiar to you.

I don't see why someone would suddenly not be able to recognize "common patterns" that they are familiar with, only because they don't have the tools at hand. A similar logic would apply to this one:

Arcana, History, Religion. You can use your knowledge of maps and locations to unearth more detailed information when you use these skills. For instance, you might spot hidden messages in a map, identify when the map was made to determine if geographical features have changed since then, and so forth.

Actually, it seems that owning the tools is only necessary for actions outside of ability checks, proper/unique to their components, for instance:

Craft a Map. While traveling, you can draw a map as you go in addition to engaging in other activity.

Because you can't possibily craft a map without the tool's components, the same logic could be applied to the other activites, suggested at the tool's table:

Activity	DC
Determine a map's age and origin	10
Estimate direction and distance to a landmark	15
Discern that a map is fake	15
Fill in a missing part of a map	20

So, is there any RAW/RAI answer to this? And how would you as a DM personally rule it?

Thanks in advance!

Answer 1

The core rules presented in the Player's Handbook require you to use your tools in order to gain the proficiency bonus. However, you are citing optional rules from Xanathar's Guide to Everything. Not all of the options in that book do require tools.

Core Rules: You must have tools to benefit from the proficiency.

The Player's Handbook explicitly says you must have the tools to benefit from your proficiency:

Proficiency with a tool allows you to add your proficiency bonus to any ability check you make using that tool. (pg.154)

Xanathar's Guide: Tables require tool use.

You cited some optional rules from Xanathar's Guide to Everything. The table of skill DCs found at the end of each entry also explicitly require the usage of tools.

You should review the "Tool Descriptions" heading on page 78. This explains how to read the entries.

In the case of the table, the Sample DCs entry says:

A table at the end of each section lists activities that a tool can be used to perform, and suggested DC's for the necessary ability checks.

If you want to employ your proficiency bonus to discern that a map is fake, then you need to use cartography tools.

Xanathar's Guide: Specific skill entries might not require tool use.

The tool entries also include a list of skills and recommended uses. These may not require actually using the tool, but the DM should adjudicate this based on the context.

The Skills entry on pg. 78 explains:

As DM, you can allow a character to make a check using the indicated skill with advantage. ... In each of these paragraphs, the benefits apply only to someone who has proficiency with the tool, not someone who simply owns it.

It goes on to explain that tool proficiency is considered abstractly here. It assumes that in learning to use cartography tools you also learned something about maps or other professional topics.

For example, the cartographer's tools have an entry for Nature:

Your familiarity with physical geography makes it easier for you to answer questions or solve issues relating to the terrain around you.

There is no obvious or rules-based reason that this requires having or using cartographer's tools (or even a map). It's a representation of the other knowledges and experiences your character gained by virtue of learning cartography.

Answer 2

Tool proficiency only helps when actually using tools

The rules on Tools state:

[...] Proficiency with a tool allows you to add your proficiency bonus to any ability check you make using that tool. [...]

From this we conclude athat proficiency with a tool does nothing other than make you better at actually using that tool. Similarly, proficiency in armor or weapons only helps you while using that armor of weapon.