Obtain an api.data.gov API key (free, instant): GET https://api.data.gov/signup
List all scanned domains: GET https://api.gsa.gov/technology/site-scanning/v1/websites?api_key={key}&limit=100 — returns domain, agency, bureau, and latest scan summary
Filter by agency: add the agency query parameter (e.g., agency=Department+of+Education) to narrow results to a single agency's web presence
Retrieve a specific domain's full scan report: GET https://api.gsa.gov/technology/site-scanning/v1/websites/{domain}?api_key={key} — includes uswds_total_score, dap_detected, https_live, and redirects_to_https fields
Export a bulk snapshot as CSV by appending format=csv to the list endpoint URL for offline analysis or dashboard integration
Compare scans over time by checking the scan_date field and polling weekly — the program runs scans nightly and historical data is retained in the API
Known gotchas
The domain list covers only the roughly 26,000 domains in GSA's inventory of federal websites; newly launched agency sites may not appear for several weeks until they are added to the scan list
uswds_total_score is a heuristic combining multiple USWDS CSS and font detection signals — a score above 100 is considered a strong indicator of adoption, but false positives occur when agencies use USWDS-like CSS without the official package
The API is proxied through api.data.gov which enforces its own rate limits (1000 requests/hour for free keys); heavy pagination should be batched and the X-RateLimit-Remaining response header monitored
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp