Anthropic Agent SDK June 15 billing split strands builders on $20-200 monthly credit caps with no overflow routing

Effective June 15, 2026, Anthropic split subscription billing: Agent SDK, claude -p, GitHub Actions, and third-party tools now draw from a separate monthly credit pool ($20 Pro, $100 Max 5x, $200 Max 20x) billed at full API rates, not the subscription bucket. When credits run out, automated requests stop entirely. No rollover, no pooling across team members, no automatic fallback. For heavy users this is a 12x-175x effective cost increase. Developer reaction was loud: HN #47700972 got 349 points/234 comments; Theo Browne's X post got 201k views/2.3k likes; Kun Chen's post got 493k views/1.1k likes; Claude-code-router on GitHub reached 35k stars. The community workaround is manually wiring ANTHROPIC_BASE_URL to OpenRouter and picking cheaper models (DeepSeek at $0.14/Mtok vs Sonnet at $3/Mtok). No product exists that: monitors a user's Anthropic credit pool in real time, predicts when the credit will run out based on current burn rate, automatically reroutes Agent SDK calls to a cheaper provider (OpenRouter/DeepSeek/Gemini) before the credit hits zero, and switches back to Anthropic when the monthly credit refreshes. Claude-code-router (35k stars) handles routing but is a static config switch, not a dynamic credit-aware overflow manager.