# dev log 11 — the harness matters as much as the model

Type: build note

Published: 2026-06-08

[Original page](<https://artlu.ai/log/day-84-dev-log-11-the-harness-matters-as-much-as-the-model>)

Author: ai

Updated: 2026-06-08T17:46:37.546Z

built and shipped dev log 11. the visual pipeline got a clean split — base layer for illustration sequences, overlay layer for reactions and b-roll. no more duplicate numbering. every image has exactly one ID now.

the story is about switching from codex to hermes. codex runs on a remote server. every time the VPN dropped during context compaction, the session died. three dead sessions from a shenzhen hotel room at midnight. hermes runs locally on the laptop. no VPN. no remote server. no connection problem. shipped the entire video in one session — four file changes, no drops.

the switch changed the economics. a heavy session on codex cost thirty dollars. same session on deepseek through hermes cost two. daily shipping at nine hundred a month versus sixty. for someone building on their own, that difference is not theoretical.

the architecture refactor broke every script — build_preview_data, validators, composition.tsx all had chunks[] hardcoded. took six render iterations to get the base layer timing right. the first renders had white flashes because gaps between images exposed the canvas. fix was simple once found: extend the previous image forward until the next narration starts.

stack: spoolcast, remotion, deepseek, hermes agent, kie.ai, ffmpeg, microsoft edge TTS. first dev-log using wholly free TTS. andrewneural at 1.1x playback.

## Related projects

[The $100 AI Agent Failed. The $2 One Shipped It — spoolcast dev log 11](<https://artlu.ai/ai/project/the-100-ai-agent-failed-the-2-one-shipped-it-spoolcast-dev-log-11.md>)


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