#respx

Invalid http_client argument: anthropic 1.x Runs on httpx2, and Two Cases the Guard Misses (2026)

TypeError: Invalid http_client argument means the anthropic Python SDK moved to httpx2 in 1.0.0. The rename is one import. The parts nobody mentions are that the guard printing that message only exists from 1.4.0, and that it cannot see your respx or OpenTelemetry layer at all (2026).