Building a Claude Code Proxy: Don't Trust Its Success Reports

Ok_Insurance_919 · reddit · 2026-08-06

A developer shared deep engineering insights on AI coding assistants while building Lupin, a local proxy that lets Claude Code use other models:

Beware of False Success Signals: Claude Code might report a session as "success" even when every request actually died on a protocol error. You must check the iserror and terminalreason fields, otherwise you risk falsely blaming the model.
Protocol Compliance ≠ Task Viability: A model can be perfectly compliant with the API protocol and still fail real tasks like exact-match edits or closing the tool loop.
Engineering Best Practices: The author emphasizes test-fixture-driven development and centralizing model quirks into a registry to prevent the codebase from scattering with if statements, allowing the agent to work long-term without drifting.

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