MCP Shifts Session Correlation Into Model Arguments, Raising 39% Multi-Turn Reliability Concerns
Updated
Updated · InfoWorld · Aug 13
MCP Shifts Session Correlation Into Model Arguments, Raising 39% Multi-Turn Reliability Concerns
3 articles · Updated · InfoWorld · Aug 13
Summary
July 28’s MCP stateless-core release did more than remove protocol sessions: it moved request correlation into explicit handles that models must pass back as ordinary tool arguments.
That design helps scaling and survives load balancers, but it makes server correctness depend on a model reliably carrying identifiers across turns instead of a protocol-managed session.
ICLR 2026 research covering 200,000 conversations across 15 models found a 39% average multi-turn performance drop, with unreliability up 112%—the same failure pattern that handle-threading relies on.
The risk is often silent: a wrong but valid-looking handle can route actions to the wrong basket, document or tenant without triggering errors, as shown by a Red Hat-cited case where $4,000 was billed to the wrong customer.
Because clients choose the model, MCP server reliability now varies by model vendor and upgrade cycle, pushing operators toward stricter per-request authorization, short-lived high-entropy handles and deeper turn-depth testing.