PR #2743 (multi-workspace MCP PR-2) made auth_headers accept an
optional ``workspace_id`` arg and self_source_headers stayed
1-arg-required. The peer-discovery-404 harness replay stubbed both
with 0-arg lambdas, so the helper call inside the replay raised:
TypeError: <lambda>() takes 0 positional arguments but 1 was given
…and the diagnostic captured by the replay was the TypeError text,
not the platform-404 string the assertion grep'd for. Caught by
PR-2737 (auto-promote staging→main) — the replay went red right
after #2743 merged into staging.
Switching both stubs to ``*args, **kwargs`` makes them tolerant of
both the legacy 0-arg call shape AND the new 1-arg-with-workspace
call shape, so neither the harness nor the in-tree unit tests need
to know which version of the runtime helpers ran the call.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>