Fable 5 Mode 4: Test-First Prompting
thisguyknowsai · x · 2026-07-03
While Fable 5 can write tests before implementation, it defaults to writing them after the code is done, much like most engineers. The author suggests reversing this: write the test suite based on specs first, then let Fable 5 run the tests and iterate until they pass, all without human intervention. This self-checking loop reportedly enabled an early user to compress a 50-million-line Ruby migration into a single day.
More from coding & agent
- Dev builds talk on guardrails workflow for shipping AI-written code without reading it — TejasKumar_ · 2026-09-11
- banteg: Codex auto-review has regressed, blocking steps needed to complete authorized tasks — banteg · 2026-09-11
- A doc-anchored agent workflow: you write, the agent only critiques and finds disagreements — lucasmeijer · 2026-09-11
- SymKit MCP: 44 tools for AI agents to verify symbolic derivations — Foreign-Specific-604 · 2026-09-11
- GitHub Copilot team routes user bug reports to an AI agent via Slack — marlene_zw · 2026-09-11
- Scanning 23 agent sessions, a dev found 3 silent failure modes in memory systems — No_Advertising2536 · 2026-09-11