Citation verification in LegalAI Space is a closed-world check. The system may only confirm an authority against a fixed allow-list of 74 approved domains: 44 UK and Irish, 18 EU and ECHR, and 12 treaty and international. They include legislation.gov.uk, BAILII, Find Case Law, EUR-Lex, HUDOC, and the FCA, ICO and SRA handbooks. Four deterministic gates run over every answer. A source outside the list cannot produce a verdict of verified, however certain the model sounds.
What 'closed world' means
The list is a set of domains held in the product's configuration, not a suggestion inside a prompt. It sits in three blocks: the UK and Ireland, the EU, and the cross-border bodies such as the UN treaty series, UNCITRAL, the Hague Conference, WIPO, the OECD, the FATF and IOSCO. The blocks are resolved per firm, so a firm working only in England and Wales does not silently inherit a wider list because someone else's firm needed one.
There is an honest edge to this. If a firm turns on a jurisdiction we hold no allow-list for, the gate stops enforcing, its summary records that the links were checked at open-web quality rather than against a closed world, and the model is told to say so. We do not cover US, Canadian or Australian law today, and an answer touching them is not a closed-world answer.
The four gates that run on every answer
A gate is code. It compares strings, ranks and URLs, and it does not ask a model whether the answer was good, because a model grading its own work is not a control. Match-set takes every authority in the deliverable and asks whether it is in the set the verification pass retrieved and confirmed; an authority in the prose but not the set is the shape a fabricated case takes.
Quote-verbatim checks that a quoted passage appears word for word in the source it fetched. Confidence-floor only ever marks work down, capping a section that cites an overruled or doubted authority. Closed-world-URL checks each host against the deny-list first and the allow-list second. All four are mandatory for LegalAI Space firms.
What a verdict actually means
Three words reach the reader. Verified means the four gates passed against a source the check retrieved from the allow-list. It is not a statement that the authority is good law, or that it supports the proposition the way the reader would like. It is a statement that the thing exists, at that address, saying those words.
Not found means the check looked and could not locate the authority on any allowed source, which is the verdict a fabricated case earns. Needs a check is where every uncertainty lands: an unavailable source, a passage that did not match, a verdict the product has not been taught yet. Nothing degrades upward. A new state costs the reader a look; it never buys a green tick.
Why we refuse paywalled sources
The deny-list holds ten paywalled domains, covering Westlaw, Practical Law, LexisNexis, Bloomberg Law, Justis and vLex. The reasons are practical, not principled. We hold no licence to those corpora. A login wall means the check cannot read the page, and something that reports a pass without having read the source is the exact failure we exist to prevent.
Every allow-listed domain is free and public, so the partner reviewing the memo can open the source. The cost, stated plainly: no headnotes, no editorial commentary, no citator signal that a case has been overruled. A firm doing serious litigation should keep its Westlaw or Lexis subscription. We are not a replacement for it.
A worked example
On our own test matters on 2 September 2026, a research question on relief from forfeiture returned an answer resting on the Law of Property Act 1925, section 146(11), the County Courts Act 1984, section 138, and the cases Billson v Residential Apartments Ltd, Shiloh Spinners Ltd v Harding and Toms v Ruberry. The searches against legislation.gov.uk and BAILII were visible while the run worked.
A second run the same day is the more useful example, because it went wrong. A Contract Agent run reported that it had checked thirty citations and verified thirty, but the match-set gate reported that none of the authorities were in the verified set, at high severity, and the Authorities table showed no verdicts. The gate was right and the sub-agent's report was worthless. We fixed the write path; we did not soften the gate.
What this does not do
The gates cannot tell you a case is bad law. There is no citator, so an overruled judgment that exists at the address given, saying those words, will come back verified. They cannot read a source behind a login, and they cannot verify an authority that is not on a free public source, so an unreported decision comes back not found even though it is real. A citation to one of the firm's own files is labelled a firm document, opens the document, and never counts as verified.
None of this is a compliance certificate and none of it is a tamper-evident chain. The inspection bundle carries a content digest, which is a smaller claim and a true one. A verified verdict is not advice. It tells you the authority is real and reachable. It tells you nothing about whether it wins your point.