v0.4.5

Fixed

• MCP transport security 421 against testserver (regression
  introduced by FastMCP ≥ 1.27 auto-enabling DNS rebinding protection
  when host is localhost). The OAuth integration test
  test_post_mcp_with_valid_token_passes_auth_layer failed in CI on
  Python 3.11/3.12/3.13 with 421 Misdirected Request — Invalid Host header: testserver because the new default allowed-hosts list
  [127.0.0.1:*, localhost:*, [::1]:*] rejects FastAPI TestClient's
  synthetic Host. Local runs missed it because the project's pinned
  mcp was still 1.13.x (no auto-protection).
• The mismatch was masked because the CI was successfully running
  pip install -e . against the unpinned mcp>=1.13.0, which now
  resolves to 1.27.0 on a clean runner — every fresh CI run picked up
  the breaking change while local devs stayed on stale wheels.

Changed

• app.stdio_server.build_server now constructs an explicit
  TransportSecuritySettings for FastMCP, controlled by three new
  env vars in app.config.Settings:
  • MCP_AEMPS_DNS_REBINDING_PROTECTION — bool, default off
    (matches mcp 1.13.x prior behaviour; CIMA data is public so the
    attack vector is low-impact, and the OAuth audience binding
    handles credential-replay risk independently). Set to true in
    production deployments behind a reverse proxy.
  • MCP_AEMPS_ALLOWED_HOSTS — comma-separated CSV of allowed Host
    header values. Defaults to a localhost-friendly set
    (127.0.0.1:*, localhost:*, [::1]:*, the same without ports,
    plus the FastAPI TestClient testserver synthetic host —
    testserver resolves to nothing in the wild so it doesn't expand
    real attack surface).
  • MCP_AEMPS_ALLOWED_ORIGINS — same, for Origin header.
• split_csv_lists validator unified across allowed_origins,
  mcp_aemps_allowed_hosts, mcp_aemps_allowed_origins.