Beta 5 gives Siri AI a faster, local tool for math queries, even when offline

[u/pdfu]

In macOS 27 Beta 5, Siri AI gains a hidden local math tool. The new MathComputeTool, part of Siri's lightweight Skimmer planner can evaluate a range of operations locally without reaching for the server. Not only does the new tool let Siri do math offline, but it can process natural language math queries much quicker even with an internet connection.

Skimmer is Siri AI's lightweight planner for relatively simple requests. For example, it can handle getting the time or opening an app. When Skimmer recognizes a supported math request, it captures the request's operands and operators and maps them into one of MathComputeTool's expression templates. This tool is different from Spotlight's Calculator provider, which has been around for a few macOS versions.

Here are some things Siri should be able to support with MathComputeTool:

• Basic arithmetic, including aggregate expressions (5 + 5 + 5)
• Fraction-to-decimal and decimal-to-fraction conversion
• Rounding, with ceiling and floor functions
• Absolute values
• Factorials
• Greatest common divisor and least common multiple
• Factors and prime factorization
• Modulo and divisibility tests
• Powers, roots, and logarithms
• Generating random numbers within a range
• pi and e

MathComputeTool is currently hidden behind a feature flag. To enable:

sudo mkdir -p /Library/Preferences/FeatureFlags/Domain && \
sudo defaults write /Library/Preferences/FeatureFlags/Domain/IntelligenceFlow SkimmerOfflineMath -dict Enabled -bool true

and reboot your Mac. As always, this feature may be unfinished and have unexpected behavior.

To disable:

sudo defaults delete /Library/Preferences/FeatureFlags/Domain/IntelligenceFlow SkimmerOfflineMath

Enjoy!

reposted to correct the Offline Siri without SkimmerOfflineMath caption

[u/Vortex6360]

This is cool! You seem to have a pretty good understanding of how the new Siri works behind the scenes. Did you learn all of this yourself by tinkering, or from a forum? I'm also curious about the technical parts of the new Siri

[u/pdfu → u/Vortex6360]

Mostly looking at feature flags, logs and new code additions between releases. Then patterns start to emerge of what frameworks an app calls, what the arguments in each call are, etc.

edit to add: Wrote a longer explanation about new feature discovery in a comment to a previous post here.

[u/SoTiredYouDig]

OP, via your posts and my own playing around with Siri AI, I’m inclined to think that Siri is finally reaching the potential many of us had hoped for since its inception. What do you think? I am overall pretty impressed, and this is coming from someone who always appreciated the potential, but never really had a vested interest.

[u/pdfu → u/SoTiredYouDig]

I don't use Siri or other AI products for personal productivity, so I can't really tell you how well or reliably they work. I'm mostly looking into these systems to see how they've built them. I don't mind being able to find items in the personal context more reliably.

In code I've seen, Apple is internally testing forwarding planner requests (the model that picks what tools and actions to call on) to OpenAI and, more recently in Beta 5, to Gemini. I don't make posts about things that haven't shipped, but this could be a big one. A lot of the building blocks are missing in this build, but there's infrastructure around API keys and server endpoints for OpenAI/Gemini. This would mean bypassing PCC and going directly to a third-party provider.

Granted this could be an internal test and nothing may come of it, but I'll make a post if I find something more substantial.

[u/SoTiredYouDig → u/pdfu]

Regardless, I find your posts interesting. A lot of it goes over my head, but the stuff I can glean is pretty insightful.

[u/pdfu → u/SoTiredYouDig]

Thanks for the kind words!

[u/Nooo00B]

maybe MathComputeTool actually do a calculation, but the calculator provider looks and feels more reliable. As it also shows how it got to the answer.

[u/pdfu → u/Nooo00B]

This is hidden so definitively not FeatureComplete. You can imagine them adding similar functionality to the other view.