[jkbennitt]

Summary

urllib.request keeps Authorization on cross-host redirects, and --base-url / TYPESAFE_BASE_URL could aim the TypeSafe API key at any host. The key is now pinned to api.typesafe.ai: other base URLs are rejected before a request, and redirects whose host is off that allowlist are refused before a second request is opened.

This is not a major production PR. It changes the tools/typesafe-pareto script and its unit tests only. No PackageId, version, CHANGELOG, or NuGet release.

What broke in live use

_http_system_one sent Authorization: Bearer <TYPESAFE_API_KEY> through urllib.request.urlopen. On Python 3.12, HTTPRedirectHandler.redirect_request copies those request headers onto the redirected request, including when Location points at another host. resolve_base_url also returned --base-url (and run_pass(base_url=...)) or TYPESAFE_BASE_URL with no host check, so the same key could be pointed at an arbitrary origin. The default remains https://api.typesafe.ai.

How you checked

• New unit tests in tools/typesafe-pareto/test_score_pareto.py (no sockets): the allowlisted default https://api.typesafe.ai is accepted and a scripted 200 receives Authorization only there; disallowed --base-url / TYPESAFE_BASE_URL values raise TypeSafeConfigError before Request, build_opener, or an injected post; a scripted cross-host 302 raises and the bearer token is recorded only for api.typesafe.ai.
• Existing suite: python3 -m unittest tools/typesafe-pareto/test_score_pareto.py -v (22 tests) and python3 tools/typesafe-pareto/score_pareto.py --smoke --force-mock --no-metrics.

What stayed unchanged

• Mock scoring, question shapes, metrics JSONL, and --force-mock when the base URL is allowlisted.
• SDK calls still go through TypeSafeClient with the same arguments when typesafe-sdk is installed. A base URL whose host is off the allowlist is rejected before that client is constructed. SDK-internal redirect behavior is unchanged.
• No NuGet package, public API, version, or CHANGELOG edits.

Checklist

• dotnet test Unsga3.slnx -c Release — not run; library code is unchanged
• CHANGELOG.md — intentionally unchanged (tools script only, not a package release)
• Public API docs — no NuGet / XML doc change
• Survival / normalization / metrics — unchanged; no oracle re-run

Test plan

• python3 -m unittest tools/typesafe-pareto/test_score_pareto.py -v
• python3 tools/typesafe-pareto/score_pareto.py --smoke --force-mock --no-metrics
• python3 tools/typesafe-pareto/score_pareto.py --smoke --force-mock --no-metrics --base-url https://evil.example exits 2 and does not write metrics