The validateAgentURL function was missing several ranges from the always-
blocked list. In SaaS mode only link-local, loopback, and IPv6 metadata
were blocked — TEST-NET (192.0.2/24, 198.51.100/24, 203.0.113/24),
CGNAT (100.64.0.0/10), IPv4 multicast (224.0.0.0/4), and fc00::/8 (IPv6
ULA non-routable prefix) were allowed through.
These ranges are never valid agent URLs in any deployment:
- TEST-NET (RFC-5737): documentation-only, no real hosts
- CGNAT (RFC-6598): never used as VPC subnets on AWS/GCP/Azure
- IPv4 multicast: never a unicast agent endpoint
- fc00::/8: non-routable prefix (fd00::/8 stays allowed in SaaS mode)
Also tighten the non-SaaS ULA block: instead of blocking fc00::/7 (the
supernet covering both fc00 and fd00), split it into always-blocked
fc00::/8 (above) + non-SaaS-only fd00::/8. This makes the SaaS relaxation
explicit and auditable.
Fixes TestValidateAgentURL_SaaSMode_StillBlocksMetadataEtAl failure.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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