MCP 2026-07-28: stateless requests + policy + registry
MCP clients
version + capabilities
on every request
Streamable HTTP
one POST per JSON-RPC message
no protocol session
OAuth 2.1 scopes
issuer + audience + expiry
scope checked per tool call
read-only MCP replicas
postgres.readonly
scope: postgres:query:readonly
s3.list
scope: s3:list
jira.search
scope: jira:read
linear / datadog / pagerduty / github / notion / slack / salesforce
10 internal tools total
OPA policy decision (per call)
Rego: allowed scopes + PII redact + payload caps
destructive MCP server
jira.create / linear.create
write scope + separate approval
postgres.write
action-bound approval required
approval record
actor + tool + args + target + expiry
registry service
publishes and indexes server.json
validates Registry schema
probes live server/discover
reports metadata/runtime drift
Registry and MCP versions are separate
audit + load
per-tenant JSONL audit log
Presidio PII redaction before write
load test: 100 concurrent clients
two replicas without affinity
receiver-side wire evidence