field notes

notes from building

Problems I ran into while building, how I investigated them, and what I changed.

2026-07-09debugging · prod · war-story1 min

the cache that never hit

cached downloads were taking up 26GB while every request rebuilt the file. the freshness check depended on a timestamp that downloading itself changed.

2026-07-09ai-agents · content · evals1 min

the reviewer that approved every draft

the marketing platform’s first model-based review missed writing problems we could already name. i split the review into explicit checks and a more focused model assessment.

2026-07-09ai-agents · knowledge-graph · legacy-code1 min

an empty result is not permission to delete

a code-graph query found no callers for a function. an agent proposed removing it, but the call happened at runtime. i changed what the tools say about missing results.

written with help from my build notes and AI drafts, then reviewed before publishing.