SenesTech, Inc.

Issuer

SenesTech, Inc.

Security title

Common Stock, par value $0.0001 per share

Principal address

Comment

This Amendment No.1 ("Amendment No.1") amends the statement on Schedule 13D field with the SEC on July 23, 2026 (as amended from time to time, the "Schedule 13D") with respect to the Common Stock of the Issuer. This Amendment No. 1 amends Item 2(b), 3, 4, 5(a)-(c), and 7 as set forth below. Capitalized terms used herein and not otherwise defined in this Amendment No. 1 have the meanings set forth in the Schedule 13D.

Principal business address

Item 2(b) is hereby amended and restated in its entirety as follows: The principal business address of each of the Covered Persons is 2207, Suite B, Bellanca St. Minden, NV 89423.

Source of funds

Item 3 is hereby amended and restated as follows: Funds for the purchase of the securities reported herein were derived from the general working capital of the Glenbrook Funds and Accounts. A total of approximately $4.33 million (excluding brokerage commissions) was paid to acquire such securities. Positions in the shares of Common Stock may be held in margin accounts. Because other securities may be held in such margin accounts, it may not be possible to determine the amounts, if any, of margin used to purchase the shares of Common Stock.

Purpose of transaction

Item 4 is hereby amended and supplemented as follows: From time to time, the Reporting Person may engage with members of the board of directors of the Issuer (the "Board") and management, and may engage with other stockholders and other relevant parties, regarding, without limitation, its concerns regarding the composition of the Board, including whether the Board, as currently constituted, has the appropriate mix of skills, experience and perspectives to oversee the Issuer's strategy and execution, and issues regarding the size, composition and refreshment of the Board, the identification of potential director candidates, Board leadership and committee composition, and the Issuer's corporate governance practices. Depending on the outcome of such discussions and other factors the Reporting Person deems relevant, the Reporting Person may take such actions with respect to the composition of the Board as it deems appropriate, which may include recommending changes to the Board, seeking to fill any vacancy on the Board, or proposing or nominating one or more director candidates for election at a meeting of the Issuer's stockholders. The Reporting Person has not made any determination as to any specific course of action, and there can be no assurance that the Reporting Person will take any such action. On October 19, 2026, GCM issued a press release and public letter regarding the Issuer, which is attached as Exhibit 99.1 hereto and incorporated by reference herein.

Number of shares

Item 5(b) is hereby amended and restated as follows: See rows (7) through (10) of the cover page to this Schedule 13D for the number of shares of Common Stock as to which the Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition.

Transactions

Item 5(c) is hereby amended and restated as follows: All transactions in the shares of Common Stock effected by the Reporting Person during the past sixty (60) days, which were all in the open market, are set forth in Schedule A hereto, and are incorporated herein by reference.

Percentage of class

Item 5(a) is hereby amended and restated as follows: See rows (11) and (13) of the cover page to this Schedule 13D for the aggregate number of shares of Common Stock and percentages of shares of Common Stock beneficially owned by the Reporting Person. The aggregate percentage of shares of Common Stock reported to be beneficially owned by the Reporting Person is based upon 5,423,542 shares of Common Stock outstanding as of August 4, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2026, filed with the SEC on August 6, 2026.

Filed exhibits

Item 7 is hereby amended and supplemented by adding the following: Exhibit 99.1 Press Release and Public Letter, dated October 19, 2026.