xAI partner integration requires Hermes to thread `encrypted_content`
reasoning items back to the Responses API on every turn so Grok can
maintain cross-turn reasoning coherence. PR #26644 (May 15) gated this
off for `is_xai_responses` on the theory that the OAuth/SuperGrok
surface rejected replayed encrypted blobs and produced the multi-turn
"Expected to have received \`response.created\` before \`error\`"
failure. That diagnosis was wrong — the prelude-SSE fallback added in
the same PR is what actually fixed that failure mode. Suppressing the
replay was an unnecessary side-effect that broke the whole point of
xAI's partnership integration.
Changes:
- agent/codex_responses_adapter.py — drop the `is_xai_responses` gate
in `_chat_messages_to_responses_input`. Keep the kwarg in the
signature for transport compatibility; update the docstring to
document the May 2026 reversal.
- agent/transports/codex.py — restore
`kwargs["include"] = ["reasoning.encrypted_content"]` on the xAI
Responses path so xAI echoes encrypted reasoning back to us.
- tests/run_agent/test_codex_xai_oauth_recovery.py — flip the three
xAI assertions (now: xAI MUST receive replayed reasoning AND we MUST
include encrypted_content in the request).
- tests/agent/transports/test_codex_transport.py — flip the
`include` assertions on `test_xai_reasoning_effort_passed` and
`test_xai_grok_4_omits_reasoning_effort`; update the allowlist
block comment.
The prelude-SSE fallback and the entitlement-403 surfacing fixes from
#26644 are untouched — they were independent fixes that happened to
ride along with the reasoning-replay gate.
Validation:
- Targeted: tests/run_agent/test_codex_xai_oauth_recovery.py +
tests/agent/transports/test_codex_transport.py → 65/65 pass
- Broader: tests/agent/transports/ + tests/run_agent/ →
1674 passed, 3 skipped, 0 failures
- E2E (real imports, isolated HERMES_HOME, ResponsesApiTransport
build_kwargs): turn-1 request carries
`include: ["reasoning.encrypted_content"]`; turn-2 input replays
the encrypted_content blob from turn-1's
`codex_reasoning_items`; native Codex unchanged.