Summary of the review

Zeng et al. developed an innovative LLM model that simulates interactions between institutional agents that can mimic reasoning, planning and action. The model is novel because it addresses key challenges that learning and memory and polycentricity and because it is linked to an agent-based model that simulates changes in land use and livelihoods. The development of the LLM model described in the paper is ambitious and challenging. Certainly, it cannot be expected that all issues and challenges are yet addressed and that it completely functions as intended. The authors describe the challenges they occur and how they may solve them. It is impressive that the authors make sure that everything becomes available open access. 

I read the paper with pleasure. It is generally well-written, novel and informative. However, there are a number of things that need improving in my opinion. That is why I recommend major revisions. In the attached pdf file, the authors can find detailed comments. Below they can find a summary of the issues that are in, my opinion, important to address. 

The experimental set up:

The intention of the paper is to test the model and simulate institutional actor’s behavior in the land system. Many different types of policy goals can be tested and different types of actors with different types of profiles and ways in which they interact can be chosen. The choices made in the experimental set up affect the outcome of the experiment. At the moment, limited rationale is provided for the experimental set up by the authors. There is no rationale provided for the choice of the SSP-RCP scenario. Additionally, limited rationale is provided for the choice of starting conditions and the types of policies that are considered. Limited rationale is provided for the choice of the combination of agents in the experiment. As this all influences the outcomes of the experiment, it is important that such rationales are provided. There is limited rationale provided for focusing only on the response of institutional agents to EU land system dynamics, without considering effects other regions in the world may have had on the results. Additionally, it is important to discuss how the experimental set up could have influenced the outcomes in unintended ways and which limitations of the model could have been accidentally missed because they did not come into play because of the way the experiment was set up. It would be great if the authors could address this thoroughly in the paper, so that the value of doing this particular experiment, but also its limitations, becomes clearer. At the moment, it was difficult for me to judge if the model is sufficiently tested using through this one experiment to run other types of scenarios with other policy targets, other institutional agents etc. Or whether more tests and sensitivity analyses are necessary for the model to be used more broadly. Especially since the outcomes of budget surplus for PAs and budget deficit for agriculture are a bit counter-intuitive in my perception and seem to reveal an overreliance of agents on policy documents.

Errors and robustness:

The authors speak of error proneness, error tolerance and robustness but these terms are not defined and the process of testing for this is not explained in the methodology. Usually, these terms are used in modelling literature in the context of quantitative sensitivity analysis but here they are used to refer to some unexpected or undesirable behavior of institutional agents. I find this personally a bit confusing, as I do not see so well how the error and robustness of the model could be derived from a qualitative assessment of the agents’ behavioral patterns. Therefore, I would recommend to either use different terms, such as undesired or unexpected agent behavior or to really well define the terms around error well and thoroughly describe in the methodology how the authors assessed the errors. If the authors would really like to emphasize error proneness and robustness in the more traditional modelling sense, I would recommend the authors to do additional analyses. For example, to add a sensitivity analysis with different starting conditions, different environmental and social goals or different combinations of agents with different profiles, etc.

Information lacking to interpret results well:

As the LLM model is linked to CRAFTY, it is of course not possible to describe every dynamic of both models in detail in this paper. However, to understand the results and discussion some fundamental modelling assumptions were missing from the main paper, such as the way the budget is modelled and how the agents, for example know how much budget is needed etc. It would be great if the authors could provide more detailed descriptions of such assumptions and modelling choices, so that the results can be more easily interpreted. Or to very explicitly refer the appendices that are adjusted in such a way that the reader can understand the results and their interpretation easily after reading them.

Writing:

Although the model is intended to mimic real-life situations, the description of the model and the results, as well as the discussion of the results remains very high-level and abstract. I would highly recommend including real-life examples of agents in the context of the EU and to discuss the results in context of dynamics at play in the EU. This would all make it a bit more tangible. In particular I would recommend including a discussion of the outcome of the model in context of what happened in the EU in the past and what has been found in previous studies.

Writing style:

The paper is generally well-written. Yet, in some parts of the paper jargon is used and quite some terms that would be up for interpretation remain undefined. It would be good to more specifically define some of the terms, so that the model and results are easier to interpret by readers of different disciplines. This is important because the model can be used in interdisciplinary settings and, when linked to other models, such as CRAFTY can influence land use modelling, which is a different field again altogether. I have put comments throughout the paper that are hopefully helpful to address this. 

In the manuscript (submitted to GMD) “InsNet-CRAFTY v1.0: Integrating institutional network dynamics powered by large language models with land use change simulation”, Yongchao Zeng, together with his collaborators, has developed a very interesting and powerful technique to use multiple institutional agents each with its own large language model (LLM) prompt history, together with a land-use change model (the latter based upon the CRAFTY model). For the entire European region, they can simulate the inter-institutional dynamics, with unstructured text (i.e., bullet-point recommendations) and numerical output being passed from one institutional agent to another, driving both the changing meat production and the changing percent of land that is a protected area. The agents that are defined are as diverse as a lawyer agent that is familiar with European law, to lobbyist agents that take the side either of agriculture or of environmental advocacy, and further to a high-level institution agent that has long-range goals in mind and that integrates the advice of other agents and prompts the other agents to try to achieve its goals. I am particularly impressed with this paper, never having imagined LLM chatbots that talk to each other, and furthermore never having imagined that these LLM chatbots can be defined with the prompt engineering to groom them as specialist institutional chatbots that can drive a land-use simulator. The writing (grammar, structure, etc.) is of very high quality. I only ask for minor revisions, which I enumerate below.

Lines 65-66: Holzhauer et al. (2019): This reference is missing in the list of references.

Line 251: Why not SSP3 or SSP5 for the changing climate? SSP1 has little change climate-wise from the current time. 

Line 286: how long is an iteration in days or months or years?

Line 296: What are the differences between the definitions and between performance of Llama-3-70b-8192 and gpt-4o, listed below in Table 1?

Line 301: Table 1: Maybe “Wiring” needs to be defined?

Line 306: Is this amount of output for the whole period of 2016-2076? Or is it per iteration? I'm a bit surprised that the amount of output is so small. If you're simulating land use over all of Europe with a 5-arcminute spatial resolution, I would expect a lot more output, especially if different countries have different policies.

Line 371: What does a “link” between nodes signify in a word graph?

Line 500: If you don't discuss this elsewhere here in this paper, it might be useful to know: how much your computers or the LLM computers need to work to produce these results? And how long from start to finish does a simulation take? 

               Also, in addition to the graphs, I would be particularly interested in seeing (for example) a time-ordered list of bullet points that are output by the various institutions. (This is to get more of a flavor of what messages are being passed between agents.)