Mo. Rev. Stat. § 67.2725
For any public meeting where a vote of the governing body is required to implement a tax increase, or with respect to a retail development project when the governing body votes to utilize the power of eminent domain, create a transportation development district or a community improvement district, or approve a redevelopment plan that pledges public funds as financing for the project or plan, the governing body of any county, city, town, or village, or any entity created by such county, city, town, or village, shall give notice conforming with all the requirements of subsection 1 of section 610.020 at least four days before such entity may vote on such issues, exclusive of weekends and holidays when the facility is closed; provided that this section shall not apply to any votes or discussion related to proposed ordinances which require a minimum of two separate readings on different days for their passage. The provisions of subsection 4 of section 610.020 shall not apply to any matters that are subject to the provisions of this section. No vote shall occur until after a public meeting on the matter at which parties in interest and citizens shall have an opportunity to be heard. If the notice required under this section is not properly given, no vote on such issues shall be held until proper notice has been provided under this section. Any legal action challenging the notice requirements provided herein shall be filed within thirty days of the subject meeting, or such meeting shall be deemed to have been properly noticed and held. For the purpose of this section, a tax increase shall not include the setting of the annual tax rates provided for under sections 67.110 and 137.055.
§ 67.2725, RSMo