Satchel Hamilton
Case studies

Work

Deep dives on the builds I'm proudest of. Each one foregrounds why the design is trustworthy — not just what it does — and ladders to the same claim: correctness under complexity, and the discipline to prove it.

  • Solo design & buildFeatured · 2026

    Congruent — proving AI-rewritten code equivalent (or finding the input that breaks it)

    Given an original function and an AI-rewritten one, Congruent returns a real answer — proven equivalent within bounds, or the concrete input where they disagree — never "passed the tests, probably fine."

    • difftest → symbolic exec → Z3 SMT
    • 10/10 fixtures decided, 0 unsound
    • Every verdict carries its bound
    • pip install congruent-eq
  • Solo design & build2026

    Toroid — an agent that writes and proves correctness properties for chips

    Point Toroid at a Verilog module and its spec: every property comes back PROVEN, BOUNDED-PASS to a stated depth, or FALSIFIED with a concrete counterexample trace — and it catches an injected FIFO bug end-to-end.

    • LLM proposes → Yosys/SymbiYosys disposes
    • 9 props synthesized live, 5/5 asserts proven
    • PROVEN only from an unbounded engine
    • pip install toroid
  • Solo design & build2026

    Kinescope — a flight recorder for AI agents (deterministic replay, counterfactual forks)

    An agent failure that was unreproducible replays bit-for-bit from a local trace — scrub to the step that went wrong, override that one decision, and watch the branched run complete live.

    • 62 offline tests, zero network
    • Anthropic / OpenAI / Gemini
    • Real run replays bit-for-bit in CI
    • pip install kinescope
  • Solo design & build2026

    Crucible — turning test-time compute into measured accuracy (or an honest negative)

    On real MATH-500 (3 seeds), search lifts a frozen 1.5B model from 38% pass@1 to 70% with an oracle verifier at N=8 — and every headline number, positive or negative, regenerates offline from committed cassettes.

    • best-of-N → beam → MCTS, one interface
    • MATH-500: pass@1 38% → oracle 70% @ N=8
    • Headline numbers replay offline in CI
    • pip install crucible-ttc
  • Solo design & build2026

    Verderer — a provable record of how public data changes

    It stands watch unattended, every six hours, against real federal data — and it has already attested its first change in the wild (a content edit to the FEMA National Risk Index) into an append-only log a stranger can verify offline, trusting neither the government nor me.

    • Live & unattended — every 6 hours
    • C2SP Merkle log · offline WASM verify
    • Bitcoin + RFC 3161 time anchors
    • First real change attested · FEMA NRI
  • Solo design & build2026

    Gatecheck — a testing layer for LLM systems

    Turns "does the new prompt/model feel better?" into a number you can diff, gate a pull request on, and watch over time — wired into CI, priced per run.

    • Deterministic graders gate CI
    • Ollama / OpenAI / Anthropic / Bedrock
    • 3 runtime deps, no SaaS, no Node
    • pip install gatecheck
  • Solo design & build2026

    Manifold — constrained-random coverage testing for AI agents

    Point Manifold at an agent and it generates seeded, fault-injected scenarios, measures functional coverage of a behavior space you declare, and biases new runs toward the gaps — reaching full coverage in roughly 20× fewer scenarios than uniform random, every failure replayable from its exact seed.

    • Coverage-directed: ~4× fewer runs to 90%
    • pass^k flakiness · seeded repro · shrinker
    • 7 invariants · live-verified on real agents
    • pip install manifold-cov