**Pyr Principles** By the use of pyr.ai, you agree to be bound by these Principles and by the Terms of Service. Pyr is based on electron microscopy images acquired at Princeton University from the CA3 region of a mouse hippocampus. The “resource creators” (see list below) are preparing a manuscript (“resource paper”) on the CA3 dataset. The resource creators have decided to make the dataset available to members of the Pyr community prior to publication of the resource paper. All neuroscientists are welcome to join the Pyr community. Membership requires acceptance of the following Principles. **Openness.** Members agree to share their proofreading and annotations of the CA3 dataset immediately with the entire Pyr community. This includes the identification of cell types and synapse proofreading. Members agree not to share unpublished information from the dataset with any individual who is not a Pyr member. **Embargo**. Members agree not to “report” (oral presentation, preprint, or submission of a manuscript for publication) their research based on the CA3 dataset during the embargo period, defined as lasting until either (1) November 1, 2025 or (2) release of the resource paper as a preprint or publication, whichever comes earliest. **Credit for the resource**. In return for prepublication access, members agree to offer authorship to the resource creators in their future reports of research using the CA3 dataset. This requirement will not apply to those members who join after the embargo period. **Credit for unpublished reconstructions**. Before reporting research based on unpublished neuron reconstructions, members agree to obtain permission from every lab that contributed “significantly” to proofreading or annotation of those cells. Contributors may request credit through co-authorship or acknowledgments, with the understanding that a few hours or days of work may not constitute authorship, but that many days or months of work most likely would. A “significant” contribution to a reconstructed cell is defined as (1) more than 20% of the proofreading edits logged for that cell, (2) verification that the cell is complete by the standards of the community, or (3) annotation of the cell with biologically meaningful information such as cell type. When contacting other members to seek their agreement for the use of cells in a research report, a lack of response within one month may be taken as agreement. Contributors to cells should not unreasonably delay or block publication by other members. If a block to publication is requested, an appeal can be raised with the resource creators, who will consider factors such as research interests and relative contributions of the labs involved. **Credit for published reconstructions**. Once cells are published, they are free to use by anyone with appropriate citations (CC BY-NC 4.0 license), without soliciting the agreement of members who contributed to the published versions of those neurons. (If a neuron is edited after publication, the use of its post-publication edited version is subject to the agreement of contributors as described for unpublished neurons above.) **Transparency**. Before reporting research, a member must submit a list of the neurons used in the research to pyr@princeton.edu, and then must make that list available in the paper. The list should include segment IDs plus coordinates of a point in each nucleus, or if no nucleus is present, a point in a main branch. **Early and active communication.** Labs are encouraged to communicate with each other as early as possible through chat, email, and other channels. Coordination of reconstruction and analysis activities will increase the pace of discovery, and prevent disputes from arising. All active members and heads of member labs should monitor the community Slack frequently to check for announcements and communications from other members. **Conflict resolution**. We have found that disputes can be avoided with communication and mutual respect. In the unlikely event that conflicts cannot be resolved by members, they will be adjudicated by the resource creators, or an advisory board. **Mutual respect.** We should all respect each others’ efforts to achieve the common goal of understanding the brain. Mutual respect fosters a win-win situation, and generates synergy that accelerates all members’ discoveries. ## Resource creators The resource creators include Zhihao Zheng, Ran Lu, H. Sebastian Seung, and David W. Tank. This list is subject to change as contributions evolve.