Jeffrey Hein@jphein
4
Events attended
2
Submissions made
United States
20+ years of experience
About me
I build AI systems that run in production rather than in notebooks: on-device neural inference on constrained hardware, agent orchestration with real memory, and retrieval over Postgres with pgvector and graph extensions. Most of my work is public. Candela is a 267,000-line Kotlin Android app I wrote almost entirely myself: four in-process neural text-to-speech engines, thirty-four content sources behind a plugin seam, on-device OCR and speech transcription, and per-document LLM chat with function calling. mempalace is a verbatim-first AI memory system on Postgres, pgvector and Apache AGE holding 335,000+ records, with 773 of my commits. dreamteam is a Claude Code plugin for memory-gated parallel agent orchestration. I work asynchronously and in writing, and I am unusually good at the parts of engineering that reward sustained precision: correctness under real data, systems that degrade honestly, and documentation an outside engineer can act on without asking me questions.
🤓 Latest Submissions
Ledger Line - a dark factory that proves its work
Ledger Line is a four-seat software factory built in BAND Desktop for the pocketful track: a wallet and payments app where money must never be created, destroyed or spent twice. Its unit of truth is a requirements ledger. For each stage, before any code exists, the lead seat turns every testable sentence of the spec into a numbered line, plus the invariants that must survive concurrency and retries and the requirements no sample check exercises. The auditor challenges the ledger first: 12 points in stage 1, 13 in stage 2. The builder hands off one work item at a time with a commit hash and an evidence block. The prover never reads product code to decide what to test: it builds a clean image with no network, runs black-box and browser tests for every ledger line, and fires concurrency storms five times each. The auditor reviews the same commit. An item ships only when both name the same hash. It caught real bad work. Stage 1: a crash on huge numbers and replays compared at 28 digits. Stage 2: a feed that silently showed only 50 payments, and a hold expiry clamped with floating-point seconds. A reset too slow on a laptop was measured in the container and fixed. It also failed honestly, and FACTORY.md documents both failures from the room log. Stage 1 deadlocked on a reply that was staged but never posted, so the stage-2 dispatch added a liveness rule. Stage 2 was cut short when an operator's helper agent stopped the seats, so neither stage has a final report. Result, in isolated mode: stage 2 claimed with 147/147 and 35/35, and stage-1 still claims stage 1. Acceptance took 18 and 28 minutes after each dispatch. The mandates are generic and never name the track.
6 Oct 2026
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Deadline Line - hear your real deadline
The people most likely to miss a benefits or eviction deadline are the least likely to have a smartphone, a data plan, or the energy to read one more letter. But everyone can make a phone call. And a missed deadline is usually permanent: Social Security's "60 days" to appeal start five days after the date on the letter; a California eviction summons gives ten court days, skipping weekends and court holidays. What it does Call the Deadline Line, or open it in a browser, say what letter you got and the date on it, and hear your real deadline: the date, how many days are left, what to do first, and a free legal-aid contact. Ask "how did you count?" and it walks through every mailing rule, weekend and court holiday. If it can't tell what kind of letter you have, it asks instead of guessing. How it's built - Speech-to-text: AssemblyAI Universal-Streaming (v3 WebSocket). Phone audio arrives at 8 kHz from Asterisk's AudioSocket; the browser streams 16 kHz audio straight to AssemblyAI with a short-lived token minted server-side, so the API key never leaves the server. Key-term prompting covers the words callers actually use. - Rules: every date comes from the Deadline Decoder MCP server, deadline rules written as tested code citing 20 CFR 404.901 and 404.933, CCP §§ 1161 and 1167, and W&I Code § 10951. No language model ever computes a date. - Voice: Piper on the phone line; the browser's voice on the web. Transcripts live in memory for the call and nothing is written to disk. - The public demo caps sessions at three minutes with per-visitor and daily budgets, since every call runs on a paid key. 55 automated tests, including a full simulated phone call, plus real SIP calls through a local Asterisk PBX transcribed live by AssemblyAI. What's next Barge-in, Spanish, a texted reminder, and a phone number TechEMPOWER, a California nonprofit, can print on flyers at libraries and food banks. Sample letters only. General information, not legal advice. MIT licensed.
30 Sep 2026
