feat(server): synthesize host:* siblings for bare allowed_hosts#537
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When an adopter passes ``allowed_hosts=['acme.localhost']`` to ``create_mcp_server`` / ``serve``, the ``host:*`` sibling (``acme.localhost:*``) is now auto-added so requests on either bare or port-suffixed Host headers pass FastMCP's transport-security check. Mirrors the port-stripping ``InMemorySubdomainTenantRouter`` does at lookup time — registering once now covers both surfaces. Salesagent adopter feedback flagged the asymmetry: their dev setup needed both ``acme.localhost`` (router) and ``acme.localhost:*`` (allowlist) per host, while the spec'd surface should accept a single declaration. Hosts that already include ``:`` (explicit port or wildcard) pass through unchanged — adopter signaled they're managing the form themselves. Idempotent: both forms in the input produce no duplicates. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Per review on #537 — flag that bracketed and raw IPv6 literals contain colons and pass through without synthesis (correctly), and point adopters at the explicit `[::1]:*` form for custom v6 hosts. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Closes #518.
Summary
When
allowed_hosts=['acme.localhost']is passed tocreate_mcp_server(orserve),acme.localhost:*is now automatically added as a sibling so the FastMCP transport-security check accepts requests on either bare or port-suffixedHostheaders.Why
Salesagent adopter feedback (issue #518): registering
acme.localhostonce inInMemorySubdomainTenantRoutercovers bothacme.localhostandacme.localhost:3001at lookup time (per_normalize_hostport-stripping). But the FastMCPallowed_hostsallowlist required both forms registered explicitly — asymmetric.This change makes the two surfaces symmetric. Single host registration in adopter code now covers both router lookup and transport allowlist.
Behavior
"acme.localhost") → both"acme.localhost"and"acme.localhost:*"registered."acme.localhost:*","acme.localhost:3001") → passes through unchanged. Adopter signaled they're managing the form themselves; we don't second-guess.Test plan
tests/test_serve_transport_security.py::*sibling:*form passes through (no bare-host auto-add)ruff,mypy, all pre-commit hooks pass🤖 Generated with Claude Code