SourceShift
Engineering notes from the SourceShift team. Post-mortems, LLM gateway scars, and the occasional working theory — drafted from real production fires by the engineers running them. No newsletter, no popups, no tracking.
- 2026may 2Probe before dispatch: the routing pattern we built without knowing it had a name
Five months of manual probing turned into seven shipped features. The literature had a name for what we were doing. We missed it for half a year.
- 2026apr 24Our prompt canary was lying to us
A 5% A/B that hid a 1.8× cost regression, and the two 2026 papers that named the fix: multi-objective Thompson sampling with a calibration gate.
- 2026apr 22The paper that proved our 5 lines of code were optimal
A 2025 paper formalized our 8-tier style profile chain as a laminar matroid. The greedy resolver we already had was the right answer.
- 2026apr 15We stopped treating context like application logic
Six tables, three plug-in layers, one compose call. The substrate every block-shaped feature on LibWit now plugs into — and the reversibility lens that decided what to lock on day one.
- 2026jan 5Our prompts stopped being code
How we built a prompt harness — registration, version control, four-tier resolution, execution ledger, feedback loop — and what the 2026 literature has been calling the same shape.
- 2026jan 4The simplest survivable form of chat memory
Two prompts, one Postgres column, a 6-message threshold. How our chat sessions keep coherence past the context window without hierarchical buffers or vector search.
