Methods
_modernFetch()?
createMcpHandler (e.g. FastMCP’s own _modernFetch).
InMemoryTransport — used by connect() above — is 2025-era only (the
legacy Server/session model); there is no in-process equivalent of a
real HTTP round trip for the modern era’s stateless-per-request dispatch.
When present, and the caller pins modern era via
versionNegotiation: { mode: { pin: '2026-07-28' } }, the client builds a
StreamableHTTPClientTransport whose fetch calls this function directly
— no sockets, but otherwise the same code path a real HTTP connection
takes. Not used for 'auto' or 'legacy' modes: this server-side hook is
modern-only (mirrors createMcpHandler(..., { legacy: 'reject' })), so
auto-negotiation (which must be able to fall back to legacy) still goes
through connect() + InMemoryTransport, and stays legacy-only for
in-process servers until a dual-era in-process bridge exists.
Parameters
request
Request
options?
unknown
Returns
Promise<Response>
connect()
Parameters
transport
Transport
Returns
Promise<void>