- Segment: reject NaN thresholds (NaN fails every comparison, so it passed the [0,1] range check and reached the shim as the literal string "NaN"); ±Inf were already caught by the range comparisons, now covered by tests too. - upstreamPath: reject '%' in model ids — %2F/%2E%2E percent-escapes decode back into path structure server-side, bypassing the literal /?#/.. rejection. Ids never legitimately contain '%'. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01WWCQcYStWXBYUy5sZWnbLT