span 01 · writing · 3 notesspan 01 · writing · 3 notes

Notes on tokenstokens, queues and tradeoffs.

1. 2026-10-04 · 9 minAgent reliability is a queueing problemA tool-using agent is a distributed system with an expensive, non-deterministic node in the middle. Retries with jitter, idempotency keys, deadlines, backpressure, checkpoints and dead letters — the backend patterns that keep agents alive in production.
2. 2026-10-04 · 8 minTenant isolation for RAG: the right answer about the wrong customerIn multi-tenant RAG the failure that matters is a correct answer about someone else's data. Session-bound tenancy, filtering before ranking, pgvector's post-filter trap, Postgres row-level security and a canary red-team suite.
3. 2026-10-04 · 6 minWhat broke while shipping the agent on this siteA closed tab that cost money, an endpoint any website could spend, an answer stuck on “thinking…”, a focus trap broken by the Enter key and a WebGL hero that scored 50 on Lighthouse — and the tests that now pin each fix.