ENGINEERING NOTES / ARCHITECTURAL RFCs
Implementation records, failure boundaries, and the reasoning behind decisions that are hard to reverse. Written after the fact, from the code that shipped.
NOTE 0018 / SYSTEMS · 16 SEP 2026
Not for speed. Determinism you can replay, resource bounds you can state in advance, and one compiled engine behind a CLI, a Python package and a browser tab — plus the hundred-fold constant error the type system was perfectly happy with. Türkçe.
DESIGN NOTE 0017 / AERA · 16 SEP 2026
Four decisions about the critic stage of an agent pipeline, and what each one costs. Three are the same rule in three places — when the reviewer's output is malformed, fail loudly. The fourth is a heuristic with a guessed threshold, written down as a guess. Türkçe.
DESIGN NOTE 0016 / AEGIS · 16 SEP 2026
The bundled churn dataset records no treatment assignment, so uplift computed on it describes the generator rather than the customer. Aegis draws the chart, labels it simulation, and excludes it from the decision path — which costs the demo its best feature. Türkçe.
NOTE 0015 / RESEARCH · 16 SEP 2026
7,358,400 archived forecasts scored against a guess that needs no model, across thirty Turkish cities and two years. In eight of them the hourly rain forecast never beats “it will not rain”, at any lead from one to seven days — and the reason is not model quality. It is how good the free guess already is where you live.
NOTE 0014 / RESEARCH · 16 SEP 2026
A long search for an edge in FX bar data, and the eight measurements that closed it. A thousand strategies that read no prices produced a best of 2,862; the best rule found by reading everything made 944, which puts it at the 90th percentile of noise. Includes the three times a measurement caught me believing something that was not there.
NOTE 0013 / PROOFFRAME · 16 SEP 2026
A released page reported the previous version. The served bytes were correct, the page was correct, and the cache-busting stamp was doing exactly what it had been written to do — which covered one of the three files that have to move together. A relative import drops the query, and the failure it produces is quiet enough to read past.
RFC 0001 / CALYBRIS CORE
A budget check and a debit cannot be separate observations. Calybris models the transition as a single state-machine step, then uses Loom to enumerate scheduler interleavings around the shared ledger. The property is not “the lock looks correct”; it is that no explored execution can authorize more fixed-point budget than exists.
NOTE 0007 / PROOFFRAME
The boundary stays columnar. Python supplies Arrow buffers; Rust validates the same memory model without turning every cell into a Python object. That removes a serialization layer, keeps nullability and physical types explicit, and gives the engine a stable unit for bounded scans, spill, fingerprinting, and evidence generation.
RFC 0012 / CALYBRIS CORE
Every record commits to the previous digest. Replay verifies framing, sequence, and the hash chain before a record can influence reconstructed state. A partial tail is an error boundary rather than an invitation to guess; recovery either proves the prefix or refuses it.
PUBLISHED ELSEWHERE
Written before these notes existed. Newer work is published here first.