[Bug] Anthropic API Error: False positive security flag on custom baseURL endpoints
Open 💬 0 comments Opened Jun 11, 2026 by KCW89
Bug Description
Running the official @anthropic-ai/sdk with a custom baseURL pointed at DeepSeek's Anthropic-compatible endpoint (new Anthropic({ baseURL: 'https://api.deepseek.com/anthropic' })) triggered a cybersecurity measure under Claude Fable 5. This is a documented, legitimate integration — DeepSeek publishes that compat endpoint specifically for Anthropic-SDK reuse, and Claude Code itself supports ANTHROPIC_BASE_URL overrides for the same purpose. Flagging it as a security event is a false positive that blocks legitimate multi-provider / BYO-endpoint development. Please scope the measure so Anthropic-SDK + custom baseURL (a non-Anthropic compatible endpoint) doesn't trip it.
Environment Info
- Platform: darwin
- Terminal: Apple_Terminal
- Version: 2.1.172
- Feedback ID: bece3709-3c60-459a-9722-a0cbb94fe93d
Errors
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