California Code, Civil Code - CIV § 1714.10

(a) No cause of action against an attorney for a civil conspiracy with his or her client arising from any attempt to contest or compromise a claim or dispute, and which is based upon the attorney's representation of the client, shall be included in a complaint or other pleading unless the court enters an order allowing the pleading that includes the claim for civil conspiracy to be filed after the court determines that the party seeking to file the pleading has established that there is a reasonable probability that the party will prevail in the action. The court may allow the filing of a pleading claiming liability based upon such a civil conspiracy following the filing of a verified petition therefor accompanied by the proposed pleading and supporting affidavits stating the facts upon which the liability is based. The court shall order service of the petition upon the party against whom the action is proposed to be filed and permit that party to submit opposing affidavits prior to making its determination. The filing of the petition, proposed pleading, and accompanying affidavits shall toll the running of any applicable statute of limitations until the final determination of the matter, which ruling, if favorable to the petitioning party, shall permit the proposed pleading to be filed.

(b) Failure to obtain a court order where required by subdivision (a) shall be a defense to any action for civil conspiracy filed in violation thereof. The defense shall be raised by the attorney charged with civil conspiracy upon that attorney's first appearance by demurrer, motion to strike, or such other motion or application as may be appropriate. Failure to timely raise the defense shall constitute a waiver thereof.

(c) This section shall not apply to a cause of action against an attorney for a civil conspiracy with his or her client, where (1) the attorney has an independent legal duty to the plaintiff, or (2) the attorney's acts go beyond the performance of a professional duty to serve the client and involve a conspiracy to violate a legal duty in furtherance of the attorney's financial gain.

(d) This section establishes a special proceeding of a civil nature. Any order made under subdivision (a), (b), or (c) which determines the rights of a petitioner or an attorney against whom a pleading has been or is proposed to be filed, shall be appealable as a final judgment in a civil action.

(e) Subdivision (d) does not constitute a change in, but is declaratory of, the existing law.