runtime: pi one-shot (-p) dies with 'Uncaught (in promise) undefined' before first output; node completes full API 401 round-trip — pi wall #8 #6660

Wall #8 of the pi bring-up (tracker #6564). GATE 1 passed (#6659: --help/--version byte-identical to node). Gate 2a differential (one-shot prompt with a deliberately bogus API key, isolated HOME):

node (bundle + assets): prints model-not-in-catalog warning + deprecation notice to stdout, then the real API round-trip result:

401 {"type":"error","error":{"type":"authentication_error","message":"invalid x-api-key","request_id":"req_011Cd..."}}

rc=1. Full fetch/TLS path to api.anthropic.com works under node with the undici-shim bundle.

perry (pi-native, same args): stdout EMPTY, rc=1, stderr:

Uncaught (in promise) undefined

Dies before the first stdout write of the -p flow (before the model warning), with the rejection REASON lost (undefined).

Repro:

cd secret-tests/pi-target/dist
HOME=$(mktemp -d) ./pi-native -p --provider anthropic --model claude-3-5-haiku-latest \
  --api-key sk-ant-bogus-differential "say exactly: hi"

(node baseline: same args with node pi-bundle.mjs; bundle assets now live at dist/dist/... next to the bundle.)

Notes for diagnosis:

• Init is proven fine (gate 1 byte-identical), so the divergence is inside the -p flow between arg parse and the first model-warning print: settings load, model catalog resolution, session setup, agent init, or the provider client construction.
• "reason=undefined" means either perry's unhandledRejection reporting loses the real Error, or something genuinely throws/rejects literal undefined under perry (e.g. an error-classification path reading a property off a value that's undefined only under perry).
• History rhymes: claude-code's fix(transform): try/catch inside an async generator never caught anything #6331 (async-generator try/catch never caught → killed API-error classification) produced adjacent symptoms. That fix is on main — but pi's code shape may hit a sibling gap.
• pi-target/dist/pi-native-dbg is a debug-symbols build; pi-native.preNNNN ladder exists for contrast.
• The projected runtime: new Blob(x) where x is an Array subclass stringifies the constructor instead of iterating elements #6232 dynamic-new-builtin-subclass wall (gaxios) did NOT fire here — anthropic provider path. It presumably still awaits on the google-provider path (pi's default provider is google, so it WILL matter for gate parity later).