https://isogeny.co.uk/log Architecture decisions, post-mortems, and trade-offs from the work we ship. en-GB Fri, 16 Oct 2026 04:43:40 GMT https://isogeny.co.uk/log/no-social-no-leaderboards https://isogeny.co.uk/log/no-social-no-leaderboards Fri, 16 Oct 2026 04:43:40 GMT 2026-10-16T04:43:40.845Z The competitors are addictive-by-design. Celer is deliberately not. DECISION https://isogeny.co.uk/log/open-tile-system https://isogeny.co.uk/log/open-tile-system Fri, 16 Oct 2026 04:43:40 GMT 2026-10-16T04:43:40.845Z Users add their own decks to tiles, rather than consuming a curated library. DECISION https://isogeny.co.uk/log/pseudonymising-cv-before-llm https://isogeny.co.uk/log/pseudonymising-cv-before-llm Fri, 16 Oct 2026 04:43:40 GMT 2026-10-16T04:43:40.845Z A token-swap pipeline replaces PII with deterministic stand-ins before any payload leaves our trust boundary. REGULATORY https://isogeny.co.uk/log/hallucination-and-data-leakage-in-production-llm-apps https://isogeny.co.uk/log/hallucination-and-data-leakage-in-production-llm-apps Wed, 20 May 2026 00:00:00 GMT 2026-05-20T00:00:00.000Z ### Context Every conversation with a buyer who's wary of AI lands on the same two fears: *will it make things up?* and *will it leak our data?* Both fears are warranted. Both are also engineering problems with engineering answers, not philosophical ones. A study we've internalised: in unconstrain SECURITY https://isogeny.co.uk/log/pgvector-over-pinecone https://isogeny.co.uk/log/pgvector-over-pinecone Wed, 15 Apr 2026 00:00:00 GMT 2026-04-15T00:00:00.000Z ### Context Celer needs vector search — embeddings over reference material so the practice engine can retrieve context for question generation. The decision was *where the vectors live*. The fashionable answers in 2026 are still Pinecone, Weaviate, Qdrant. They're genuinely good products. The unfa INFRASTRUCTURE https://isogeny.co.uk/log/walkie-talkie-before-live-conversational https://isogeny.co.uk/log/walkie-talkie-before-live-conversational Fri, 03 Apr 2026 00:00:00 GMT 2026-04-03T00:00:00.000Z ### Context Celer has two audio-practice modes on the roadmap: - **Walkie-Talkie** — turn-based. You speak, the question stops, the model thinks, the answer plays. Like a slow phone call. - **Live Conversational** — full duplex. Streaming STT in, streaming TTS out, interruptible, with latency unde PRODUCT