For research communities negotiating transformative agreements, they are not only a mechanism to understand and redirect spending on publication outputs and APCs—they are, perhaps more importantly, a way of bringing libraries directly into the mechanics of scholarly publishing. Negotiations expose the true costs of the system, revealing that the subscription fees institutions have been paying for years are often higher than the publishing costs that are now under scrutiny. This shift in visibility is transformative in itself. It enables libraries, funders, and scholars to make informed decisions, to question entrenched assumptions, and to draw on models such as SciELO’s that align investments with open access objectives. The more we understand the real economics of publishing, the more agency we gain in reshaping it.