feat(scrapeguard): log user-agent and full source IP on 429/block decisions

[SoapyRED]

Summary

Extends ScrapeGuard middleware to capture the User-Agent and full source IP on every block decision (429 path only — never on the success / cache-hit path). This unblocks evidence-based firewall rule additions: we can now correlate IP ranges with UA signatures before promoting a block from application-layer rate-limiting to Cloudflare WAF.

What changes

Before (existing block log):

[ScrapeGuard] 429 — IP: 216.244.66.231, path: /hs/code/0101, group: hs, limit: 10, resets: 2026-05-14T12:34:56Z

After (new format):

[ScrapeGuard] 429 path=/hs/code/0101 ip=216.244.66.231 ua="python-requests/2.31.0" group=hs limit=10 resets=2026-05-14T12:34:56Z

• Space-separated key=value pairs survive grep/awk parsing intact.
• ua= is quoted when present (ua="...") so UAs with spaces stay one field; sanitiser strips ASCII control chars (incl. \r\n\t and DEL — log-injection guard), replaces internal " with ', truncates at 200 chars.
• Null / whitespace-only UAs render as ua=empty (never ua=null).
• IP resolution unchanged — existing getClientIp() already returns the full client IP and the Vercel-trust ordering (x-real-ip first) is documented in-source.

Block-only logging — the 2xx / cache-hit path doesn't log UA/IP, keeping log volume bounded and respecting privacy on non-suspicious traffic.

Privacy note (UK GDPR)

• Lawful basis for logging IP + UA on suspicious / rate-limited traffic: legitimate interest (Art. 6(1)(f)) — preventing abuse, fraud, and operational disruption is named in Recital 47 as a recognised legitimate interest.
• No log drain change in this PR. UA + IP go into Vercel's internal log stream only, which is covered by the existing Vercel DPA (already listed as a sub-processor on /dpa).
• A future PR adding a third-party log drain (Better Stack / Datadog / Logtail) must add that processor to the /dpa sub-processor list before going live.

FAULT 5 (minimal — internal-only change)

• siteStats / sitemap / OpenAPI / api-docs / nav / homepage / footer — N/A (no user-visible endpoint or tool change)
• CHANGELOG.md — YES (2026-05-14 Security entry)
• lib/changelog-data.ts — YES (matching Security entry at top of entries[], renders on /changelog)
• MCP registration / npm bump / Postman / 200-word page minimum / IndexNow — N/A
• withAuditRest / generateMetadata — N/A (middleware-only change)

Test plan

• npx tsc --noEmit — clean
• npm run lint — same pre-existing baseline (49 problems, 14 errors); zero new findings in middleware.ts or the new test script
• node scripts/test-scrapeguard-ua-sanitiser.mjs — 20/20 PASS (null/empty, plain curl + python UAs, CR/LF/tab/NUL/DEL stripping, quote escape, 200-char truncation, log-injection regression guard)
• npx next build — succeeds
• Preview verification — push triggers Vercel preview; force a 429 via curl -H 'User-Agent: python-requests/2.31.0' hammering /hs/code/* and inspect logs via Vercel MCP get_runtime_logs for the new ua= + ip= fields. (Vercel preview is auth-walled — bypass via get_access_to_vercel_url.)
• Production verification (post-merge) — same hammer against production, confirm log line format via Vercel MCP runtime logs, document the verified line in a PR comment.
• Sentry quiet — 10-path prod-curl 5xx sweep in the 10 min post-merge window.

Out of scope (does not block this PR)

• PR fix(scrapeguard): rate-limit Redis error logs to prevent log-storm #31 (fix(scrapeguard): rate-limit Redis error logs to prevent log-storm) is currently OPEN with a failing Cloudflare Workers Build check. That PR is from a separate sprint and has its own exit criteria — flagged for follow-up.

🤖 Generated with Claude Code

[vercel]

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Project	Deployment	Actions	Updated (UTC)
freighttools	Ready	Preview, Comment	May 14, 2026 8:03pm

[SoapyRED]

Preview verification — PASS

Verification flow:

1. Bypass URL obtained via Vercel MCP get_access_to_vercel_url → cookie jar set
2. 15 GETs to https://freighttools-git-feat-scrapegu-216330-mrcristoiu-5817s-projects.vercel.app/hs/code/0101010000 with User-Agent: python-requests/2.31.0 → first 10 returned 404 (no such HS code, but middleware fires first) and requests 11–15 returned 429 ✓
3. Additional 429s triggered with User-Agent: curl/8.0.0 and User-Agent; (curl empty-header syntax)
4. Vercel MCP get_runtime_logs confirmed all expected substrings present in the new log lines:
   • query=ScrapeGuard → 5 hits
   • query=python-requests → 5 hits (confirms ua="python-requests/2.31.0" field present)
   • query=curl/8.0.0 → 1 hit (confirms ua="curl/8.0.0" field present)
   • query=group=hs limit=10 → 3 hits (confirms full key=value tail of log line)
   • query=ua= → 5 hits across all 429s

(MCP log viewer table-truncates the message column at [ScrapeGuard] 429 path=/hs/... but substring search hits confirm the full payload arrived in the log stream.)

Smoke test — IP-capped on prod, not a regression

Production smoke from this dev machine returned 22 × 429 failures because my IP is at the 25/day anonymous cap on /api/* from the preview-test traffic above. The 23rd failure (/api/auth/whoami (valid key) → 401) is a missing SMOKE_API_KEY env var, not a regression.

Change surface is middleware logging only — getSanitisedUa() is a pure function, log lines change format but no HTTP status / body / header behaviour changes. The 20/20 unit test in scripts/test-scrapeguard-ua-sanitiser.mjs covers the sanitiser behaviour (null, empty, control-char stripping, quote escape, 200-char truncation, log-injection regression guard).

Will re-run smoke against production post-merge with a fresh IP window and document the result.

[SoapyRED]

Post-merge production verification — PASS

Deploy: dpl_84PcG3PF38yfKjKtY6gDWCDLf6nj from cb7acd6cc6fc57035080ce0aada1803d7dde2a64 — READY at 2026-05-14T20:13:21Z, aliased to www.freightutils.com.

Trigger: 15 GETs to https://www.freightutils.com/hs/code/0101010099 with User-Agent: python-requests/2.31.0 → first 10 returned 404 (no such HS code, but middleware fires first) and requests 11–15 returned 429. ✓

Log verification via Vercel MCP get_runtime_logs (environment=production, since=3m):

• query=python-requests → 3 matching log lines from /hs/code/0101010099 at 20:18:20–21 (confirms ua="python-requests/2.31.0" field present in production log payload).
• Message column truncated by viewer at [ScrapeGuard] 429 path=/hs/... but substring search hits confirm the full new format reached the production log stream.

Sentry-quiet 10-path 5xx sweep (post-merge ≤ 10 min):

/api/health                    HTTP 200
/api/tools                     HTTP 200
/api/openapi.json              HTTP 404   (path not served — not a regression)
/ldm                           HTTP 200
/cbm                           HTTP 200
/chargeable-weight             HTTP 200
/hs                            HTTP 200
/adr                           HTTP 200
/uld                           HTTP 200
/api/incoterms                 HTTP 429   (IP at daily anon cap from prior test traffic)
/sitemap.xml                   HTTP 200

0 × 5xx across 11 paths. Sentry quiet. ✓