The original smoke step had `assert a2a_client._A2A_QUEUED_PREFIX`
which is a feature-flag-style check — it fires false-positive every time
staging is mid-release of that specific feature. Caught when the dry-run
publish (run 24965411618) failed because _A2A_QUEUED_PREFIX hadn't
landed on staging yet (it lives in PR #2061's series, separate from the
PR #2103 chain that shipped this workflow).
Replaced with checks for stable invariants of the package contract:
- a2a_client._A2A_ERROR_PREFIX exists (always has, since the
[A2A_ERROR] sentinel is the foundational error-tagging primitive)
- adapters.get_adapter is callable
- BaseAdapter has the .name() static method (interface anchor)
- AdapterConfig has __init__ (dataclass present)
These four cover the cases the smoke test actually needs to catch:
import-path rewrites broken by build_runtime_package.py, missing
modules, dataclass shape regressions. They don't fire when a specific
feature is mid-merge.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: Hongming Wang <hongmingwangalt@gmail.com>
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