Replit's Marketing Agent Is 14,230 Lines of Code Running on Haiku for $254/Month — and It Rewrites Its Own Prompts Nightly

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Replit and SaaStr detailed two production agents: 10K, an autonomous VP of Marketing at 14,230 lines of code, and QBee, an autonomous VP of Customer Success managing 100+ sponsors on a daily QBR cadence at 70% fewer human hours than a comparable B2B media operation. 10K costs ~$254/month incrementally, runs largely on Claude Haiku and Mini rather than frontier models, sent 331 investor outreach emails with zero send failures, and drove $1M+ in closed agent-sourced pipeline with 72% open rates on win-back campaigns — with three humans and 20+ agents running the operation. The architecture worth stealing: context compaction, long-term markdown memory files (replit.md), a monorepo giving agents global business context, and a self-improving loop where the agent reviews nightly traces, opens prompt-change PRs, and A/B-tests them itself.