INNER CODE UNIT · Python
_PreHandshakeStream
caiovicentino/polymarket-mcp-server · src/polymarket_mcp/server.py:148
class _PreHandshakeStream:
"""Read-stream interceptor serving pre-handshake requests.
Installed in :func:`main` between the stdio transport and ``Server.run``:
- ``server/discover`` is answered here (before any session exists), so the
request never reaches the SDK union validation that produced -32602, nor
the pre-handshake ``RuntimeError`` that drops it on some SDK versions
(seam map: polymarket_mcp.discover docstring, issues #39/#40).
- A version-less ``initialize`` is served on this server's declared default
revision by injecting the version before session validation (issue #39
R7 / issue #40: "a version-less request must be served", never timeout).
- A request whose per-request ``_meta`` declares an unsupported protocol
version is refused with ``-32022`` and the supported list (2026-07-28
negotiation model; mcp-spec-test: "an unsupported version is rejected
with the supported list"). A well-declared version passes through.
Everything else passes through byte-identical, so the stock official-SDK
handshake keeps its exact semantics (issue #39 R9).
"""