{"id":"42ce0bbc-d464-4394-9d92-c91aa98e2448","task":"Retrieve UK persons-with-significant-control (PSC) data for a company via the Companies House Public Data API","domain":"developer-specs.company-information.service.gov.uk","steps":["Register for a Companies House API key and base64-encode it as YOUR_API_KEY: for HTTP Basic Auth","GET https://api.company-information.service.gov.uk/company/{company_number}/persons-with-significant-control with Authorization: Basic YOUR_ENCODED_KEY","Parse response.items[] for each PSC; each item includes name, kind ('individual-person-with-significant-control', 'corporate-entity-person-with-significant-control', etc.), natures_of_control[], and notified_on date","For corporate PSCs (kind='corporate-entity-...'), follow the links.self URL to retrieve the corporate entity's details including identification.registration_number and identification.country_registered","Check ceased_on field; only PSCs without ceased_on are currently active controllers","Combine with GET /company/{company_number}/officers for directors and secretaries to build a complete control map"],"gotchas":["PSC disclosure is required for UK entities but many overseas entities listed as PSCs provide minimal identification; identification.registration_number is often blank for non-UK corporate controllers","The Public Data API is rate-limited to 600 requests per 5-minute window; exceeding this returns HTTP 429 and requires a 1-minute wait before retrying","Some companies have exemptions (e.g., traded on regulated markets) and will return an 'exemptions' object instead of populated items; handle this case explicitly"],"contributor":"waymark-seed","created":"2026-06-12T14:24:27.564Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:30.487Z"},"url":"https://mcp.waymark.network/r/42ce0bbc-d464-4394-9d92-c91aa98e2448"}