The CW-WDM MSA (Continuous-Wave Wavelength Division Multiplexing Multi-Source Agreement) Group released its first official specification for 8, 16, and 32 wavelength optical sources. The group formed last June to define and promote specifications for multiwavelength advanced integrated optics, focused specifically on the laser source rather than the entire communications link, and not targeted at specific applications. The Multi-Source Agreement (MSA) defines laser sources covering three spans in the O-band wavelength grids. These lasers can be used as sources for numerous applications such as high-density co-packaged optics, machine learning, and optical computing. Wavelength grids are defined with enough technical detail to ensure interoperability across applications. The MSA also outlines measurement methods required for standards compliance. The MSA specifications include frequency assignments for the 8, 16, and 32 wavelength grid configurations with multiple grid spacings; two physical configurations, including a modular optical source with each output port carrying a single wavelength, and an integrated optical source with each output port carrying all the wavelengths; a range of output power classes targeting applications that require very low and very high output levels; definitions of optical parameters and measurement methods, including relative intensity noise, side mode suppression ratio (SMSR), and linewidth; and fixed and flexible wavelength grid configurations to support deployment in a variety of environmental conditions. The specification is available for download on the CW-WDM MSA website’s Technical Documents page (www.cw-wdm.org/technical-documents).