Legal: California signs lawyer AI law as assistants reach small firms

California's lawyer AI law, the first US state statute on how lawyers use generative AI, was signed on 30 September 2026 and takes effect on 1 January 2027. It makes the lawyer who files a paper in a California court personally responsible for reading every citation in it, requires disclosure when AI helped write it, and keeps client information out of open-access AI tools. In the same three weeks, AI assistants reached the practice software small firms already pay for, so small offices now face the new duties and the new tools at once.

What changed since we last looked

When Era Haus last looked, in Legal: OpenAI enters legal research as the checking duty spreads, the California bill was waiting on the Governor. Gavin Newsom signed it on 30 September (Bloomberg Law, 30 September).

The law, SB 574, amends California's court-filing rule so that a paper may not contain any citation the responsible lawyer has not personally read and verified, "including any citation provided by generative artificial intelligence." The law firm King & Spalding notes in its summary that this covers every filing, AI-drafted or not, and it runs through the existing sanctions process, which gives a lawyer 21 days to withdraw or correct a paper before the court acts. Lawyers must also disclose when generative AI helped produce a document filed with a court (Holland & Knight, 1 October; Bloomberg Law), and Bloomberg Law calls that the one genuinely new duty, since the rest restates ethics guidance.

The law also bars confidential or personal client information from open-access AI tools, enforced through State Bar discipline. Tools limited to the lawyer and people bound to keep the client's confidences remain allowed, per Holland & Knight.

US courts already sanctioned invented citations case by case. The statute writes the duty down, attaches it to every filing in the state, and adds a licensing consequence for putting client data in the wrong tool. Spain had already reached a similar line by another route. In April 2026 the Consejo General de la Abogacía, the national council of Spain's bar associations, issued an interpretive circular treating unchecked AI output as a professional failing, and its ethics chair warned that a serious breach can mean suspension of between 15 days and a year (Abogacía Española, April 2026; Vozpópuli). We found no new rule or launch in Latin America dated in these three weeks.

The assistant moved into software small firms already use

On 23 September, 8am (the company behind MyCase, a practice-management system popular with small US firms) released a connector that lets Anthropic's Claude assistant read a firm's MyCase data. It covers cases, clients, documents, invoices and new-client intake, 73 actions in all. It can read records but not change them, and it follows the permissions already set in MyCase. The company says more than 60 practices used it in a quiet month before launch, most with five lawyers or fewer (Business Wire, 23 September; LawNext). The gain is practical: a partner can ask about a matter or an unpaid invoice without copying files into a chat window.

Spellbook, a contract-drafting tool that runs inside Microsoft Word, put its contract-management product on general release in early October (Artificial Lawyer, 7 October). It takes requests from email, reviews drafts against a practice's own standard positions, checks the other side's edits, and stores signed agreements in a searchable archive. No price is published. In both launches the tool works from what the office already has: its records, its standard positions.

Clients and new firms are pricing routine work

On 8 October AT&T said its in-house legal unit, LegalEdge, will work with OpenAI as a design partner to build AI workflows for legal tasks under lawyer supervision (AT&T newsroom, 8 October). LegalEdge was set up in January 2026 with about 38 legal staff to bring in-house work, such as document review and drafting, that AT&T used to send to outside firms.

Arceus, a San Francisco law firm built around AI, raised $17 million on 1 October to sell contract review at fixed, quoted prices, with no charge if a standard review takes longer than eight hours (Artificial Lawyer and SiliconANGLE, 1 October). And on 7 October Harvey, the best-funded legal AI startup, released a workflow built with LexisNexis, a large paid legal-research publisher, that drafts a motion to dismiss, the request to throw out a lawsuit early, from US case law in stages a lawyer approves along the way (Harvey, 7 October).

What it means for you

If you practice in California, from January every paper you sign carries your personal assurance that you read each case it cites, and a statement when AI helped draft it. The cost is time, and it lands on the routine filings where AI saves the most. The confidentiality duty matters more for daily work. A free or consumer AI account is the plain risk, and a connector like MyCase's is only as safe as the AI account on the other end of it. Outside California the statute has no force, but it is the first written version of a duty that courts in the US, the UK and Spain already enforce one case at a time.

On pricing, the pressure now comes from both sides. A large client is building its own AI legal team to keep work in-house, and a venture-funded firm sells fixed-price contract review. Routine contract and motion work is where an hourly bill is hardest to defend.

What to do about it

List every AI tool that touches client information in your office and, for each, whether the account is limited to your firm under a confidentiality agreement or open to the public. If you practice in California, move anything in the second group before January, and agree one standard wording for disclosing AI use on filings; everywhere else, treat both as good practice. Add one line to your filing checklist: the signing lawyer has read every cited authority. If you run MyCase, try the Claude connector on one matter before connecting the whole practice. On the new contract-management products, watch until they publish prices.