The authors present an interesting new hydrologic modelling toolbox in Python. The toolbox itself is very interesting and the publication is appropriate for GMD. I have a few points that the authors might want to address to improve their manuscript.

(1) The toolbox itself is interesting and is mostly well described. What took me a while to understands though, is whether the toolbox models only described 1-D soil processes or whether they can present a grid with spatial variability. As well as how this raster would be connected. My suggestion is that the authors expand Figure 1 to also include spatial and temporal discretization, as well the inputs to the model. I think it would help the reader to have such a conceptual figure regarding the possible model architectures.

(2) A related aspect is the very specific input requirements for the model discussed in lines 112ff. I am a bit confused why this is so specific when the model architecture is meant to be modular. Should the model not be adjustable to the data available? Precipitation of 10 minute time steps or less will limit available datasets very much. Why can the model not be run with hourly time steps? Especially given that other inputs are daily. I think the authors should provide some justification here, rather than just stating this as a fact.

(3) Another part where I would expect a bit more discussion is section 2.2. Much has been published on the issue of modular hydrologic models over the last 20 years, but hardly anything from this discussion is mentioned here (e.g. https://gmd.copernicus.org/articles/12/2463/2019/gmd-12-2463-2019.pdf). This discussion should also include how a certain process module (e.g. transpiration or surface runoff) could be represented using different process complexities. I assume this is included here.

(4) Could the authors expand a bit on the numerical implementation of the models and how this links to previous discussions on the topic (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2009WR008894)?

(5) In line 248, the authors mention that parameters are randomly generated, but do not explain more. I assume the authors sampled from independent uniform distributions. Are there other options than this approach? Here the link to other toolboxes might be particularly useful to further explore the model outputs given that more and more analysis algorithms can be run with generic input samples (e.g. https://www.sciencedirect.com/science/article/abs/pii/S1364815218303220).

(6) If the model is represented as a grid, is there a possibility for river flow actually occurring? Or is the domain limited to plot scales where channelized flow might not occur?

(7) A hydrologic modelling toolbox like the one presented here can (and probably should) link to a wider range of Python toolboxes that assess and attribute uncertainties (e.g. https://safetoolbox.github.io/) or estimate parameters (e.g. https://pymoo.org/). Discussing how one might use existing toolboxes with RoGeR would be interesting for users I believe.

(8) There are a few issues with the writing. E.g. "measurements for their states" should be measurements of, the last sentence in the abstracts includes and twice and is too long, ... So please have another read through just for grammar.

This paper presents a python library to implement RoGer hydrological model. The main reason behind developing this library was to provide an-easy-to-use, reproducible and modular code. The library itself can be quite useful given that it also tries to simulate water isotope data.

A major limitation of the paper is that it does not represent a real-world application of the code; we do not learn much by the synthetic example shown. The real challenge in implementing a distributed hydrological model is estimating the parameters that should be used for simulations, especially given the uncertainties in already limited hydrological data. Therefore, I suggest that the authors present a real-world case study in the paper. Also, a brief discussion of the calibration problem might benefit the paper; is there any plan to include calibration modules in the package?

My specific comments are in the attached PDF.