13. California's 2026-03 Billing Bulletin and Colorado's Rule 1.0 AI Definition Signal Coming Disclosure Mandates
Two state developments in spring 2026 foreshadow where formal AI disclosure obligations are headed.
BY MIDSIZED DESK · JUNE 2, 2026 · 1 MIN READ
Two state developments in spring 2026 foreshadow where formal AI disclosure obligations are headed. California's Standing Committee on Professional Responsibility issued Practical Guidance Bulletin 2026-03 in March 2026, recommending (not yet requiring) that attorneys inform clients when AI tools are used in substantive legal work, and specifically flagging that billing AI-assisted research at traditional rates may raise fee reasonableness issues under Rule 1.5. Colorado became the first state to embed AI terminology directly into its Rules of Professional Conduct, amending Rule 1.0 in January 2026 to add a formal definition of "artificial intelligence tool." Washington's AI Task Force interim recommendations (April 2026) propose the most nuanced framework yet — a tiered disclosure system based on AI application risk level. As of June 2026, at least 34 state bar associations have issued some form of AI guidance. Midsized firms should review their engagement letter language and billing descriptions against the most restrictive applicable standard.