https://www.courts.ca.gov/cms/rules/index.cfm?title=three

California Rules of Court Rules 3.890-3.898 implement the Civil Action Mediation Act, which applies in the Superior Court of California, Los Angeles County, and other courts that choose to follow the Act. Cases are submitted to mediation if the court so orders when each plaintiff has more than $50,000 in controversy or the parties stipulate to mediation at least 90 days before the trial is set to begin. The parties can stipulate to any mediator or the court will assign a mediator to the case from the court-approved list of mediators. The rules require parties to attend each mediation session unless the mediator excuses or permits them to participate by telephone, and each party is allowed to have counsel present at every mediation session. At the end of the mediation, the mediator must complete and file with the court a Statement of Agreement or Non-agreement. The parties must exercise restraint on discovery during mediation or the court can issue a protective order. Each court must provide information on available ADR processes to parties who request it.