Formal Methods × Generative AI

From AI you hope is right
to AI you can prove is right

A plug-and-play layer that verifies every reasoning step of your LLM against your rules, in real time. Any model, no retraining.

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What you get

Every step verified against your rules

Example: an AI assistant helping engineers choose materials for an aircraft part, verified against the company’s engineering rules

Without Formel AI

Engineer asks“Can we replace the titanium (Ti-6Al-4V) in this support part with something lighter? It carries 12 kN.”
↓
Agent drafts“Use 7075-T6 aluminium”
↓
No verificationFatigue limit exceeded: the part would crack after repeated loads
↓
OutputA part that would crack in service enters the design
↓
Human checkCaught in design review, if at all

With Formel AI

Engineer asks“Can we replace the titanium (Ti-6Al-4V) in this support part with something lighter? It carries 12 kN.”
↓
Agent drafts“Use 7075-T6 aluminium”
↓
Formal verification · blockedViolates the fatigue-limit rule: aluminium would crack under repeated loads
↓
CorrectionCompliant material proposed
↓
OutputSafe material + reasoning certificate for certification

How it works

A formal layer around your LLM

1 · Plug in

Any LLM, your infrastructure

Works with any open or closed-source LLM, no retraining. Our layer itself is CPU-only: one container, deployable in any cloud (AWS, GCP, Azure…), on-premise or air-gapped.

2 · Verify

Logic rules + your rules

Logic rules catch contradictions from day one. Your rules (regulation, internal policy, engineering constraints) are written in plain language and set up in days.

3 · Prove

An answer you can audit

Every answer comes with a reasoning certificate: a graph of each assumption and deduction. A step that can’t be verified is flagged, never silently passed.

Business impact

From “we can’t put AI in production”
to “we can prove it”

5x
cheaper AI deployment

Fewer tokens and fewer people: smaller models, no judges, no human review

Use cases that were too expensive become profitable

0
silent reasoning errors

Every step is verified or flagged, never passed unchecked

Incidents, rework and escalations avoided

100%
auditable

Every answer ships with the proof of its reasoning

Unlocks defense, critical infrastructure and regulated sectors

In practice

Without Formel AI With Formel AI
Model size LargeModels are over-sized to compensate for unreliability SmallerReliability comes from the formal layer
LLM-as-a-judge 10+One judge is needed per business rule 0Rules are verified formally instead
Manual review 10+ peopleThey review 10,000+ answers/month NoneFormel AI flags the wrong ones

Who benefits

Built for every stakeholder

Tech Lead / Product Manager

Engineering & Product

  • Domain experts write each rule once, in plain language
  • Rules are easy to update if requirements change
  • No retraining, no change to your existing agents

CISO / Compliance Officer

Security & Compliance

  • Runs in your cloud or on-premise, even air-gapped
  • A reasoning certificate for every answer, ready for auditors

End user

Trust & Adoption

  • Trust the answer without re-checking it
  • See why the AI reached its answer

Who we are

Meet the team

Co-founders

Sylvain Combettes, PhD
CEO

Prev. Senior ML Product Engineer at Probabl, the Inria spin-off and official operator of scikit-learn. Former data science lecturer at Ecole polytechnique (EXED and X-HEC Data Science for Business MScT) and CentraleSupélec EXED. PhD from ENS Paris-Saclay.

Antoine Mazarguil, PhD
CTO

Prev. ML Engineer at Qubit Pharmaceuticals, after working on the company’s HPC calculation management as a Software Engineer. PhD from ENS Paris-Saclay, MSc from Ecole polytechnique and MVA (Mathématiques, Vision, Apprentissage).

Founding team

Aliénor Chateau
Strategy and Operations Associate

Prev. Social Commerce Lead at Primelis, VC Analyst at Eurazeo and Plug & Play. MiM from ESCP.

Antoine Gagelin, PhD
Research Engineer

Prev. Data Science Lead at Qubit Pharmaceuticals. PhD from Université Paris Cité, MSc from ESPCI and Sorbonne Université.

Carlos Pinzón, PhD
Research Engineer

Prev. postdoc at Inria. PhD from Ecole polytechnique.

Ciarán Dunne, PhD
Research Engineer

Prev. postdoc at Inria and ENS Paris-Saclay (Deducteam). PhD and MSc from Heriot-Watt University.

Firas Jarboui, PhD
Senior Member of the Technical Staff

Prev. Head of ML at Gorgias, Lead ML Engineer at Agicap. PhD from ENS Paris-Saclay, MSc from Ecole polytechnique and ENSTA.

Guillaume Genestier, PhD
Research Engineer

Prev. Senior Software Engineer at Nomadic Labs, Alstom, and Tweag. PhD from ENS Paris-Saclay (Deducteam) and Mines Paris, MSc from Ecole polytechnique.

Nathan Vaneberg
AI Engineer

Prev. AI Engineer at BNP Paribas and Full-Stack Engineer at Qubit Pharmaceuticals. MSc from Ecole polytechnique and ULB.

Raphaël Selz
AI Engineer

Prev. ML Engineer at Gorgias. MSc from Oxford, BSc from EPFL.

Business angels

Emmanuel Blanchet
Co-founder of Deepki and CheckDPE
Florian Douetteau
Co-founding CEO of Dataiku
Karl Tuyls, PhD
CTO AI at Imec, ex-Director at DeepMind and Meta
Martin Raison
Co-founding CTO of Nabla
Olivier Pomel
Co-founding CEO of Datadog
Vincent Luciani
Co-founding Executive Chairman of Artefact

and many more…

Start with one use case

A pilot on your own LLM and rules, live in about three weeks

Get in touch