Aristotle
Mathematical superintelligence with every answer formally verified in Lean 4 — IMO gold, zero hallucinations by construction.
About
Aristotle is Harmonic's bid for what it calls mathematical superintelligence: an AI mathematician that writes its reasoning in Lean 4 and only shows you answers that pass the compiler. That design choice kills an entire class of failure — a hallucinated step simply cannot survive formal verification — which is why mathematicians use it to check proofs and hunt for errors in LLM-generated mathematics.
The headline result is gold-medal-level performance at IMO 2025, with 5 of 6 problems solved under formal verification. Backed by a $1.45B valuation after its Series C, Harmonic has put Aristotle in researchers' hands through a free web app, a CLI and an API beta. It is closed and expensive to run, and every capability claim traces back to the company itself, but nothing else on the market offers verified mathematics at this level.
Specs
Context window
Pricing
Free quota
API access
Weights
Released
Benchmarks
- Vendor-reported (Harmonic, 2025): gold-medal level at IMO 2025 — 5 of 6 problems solved with formal verification
- Third-party report: 96.8% on the VERINA code-verification benchmark (not vendor-confirmed)
Provider-reported unless a source says otherwise. Benchmarks are marketing-adjacent by nature — treat them as directional.
Use cases
Trust score — 7/10
Scored 7/10 (TIER verified, metrics-v1). Evidence: Harmonic Series C announcement (Nov 2025, $120M at $1.45B) confirming IMO gold-medal claim and public availability; founded by Robinhood CEO Vlad Tenev; API beta and free web app confirmed by third-party reporting. Strengths: unique formally-verified design, strong funding, real researcher adoption. Docked for: (1) closed system — no weights, no paper, no independent replication; (2) all capability claims are vendor-reported. License: proprietary.
How the trust score is built
Full methodology →- Adoption · stars/downloads, log-scaled vs peers
- 7.0/10
- Maintenance · recency, releases, issue load
- 8.0/10
- Openness · license + docs
- 2.0/10
- Manual review · sanity read + red-flag check
- 7.0/10
- · Harmonic; public launch 2025; Series C $120M at $1.45B (Nov 2025)
- · IMO 2025 gold-medal level (5/6), Lean-4 verified
- · All capability claims are vendor-reported