The text of Trump's agreement with the Taliban is at this US State Department address:
https://www.state.gov/wp-content/up...or-Bringing-Peace-to-Afghanistan-02.29.20.pdf
Although it is not clear if this is the final version. The document file name contains the word "Draft". It mentions in the pre-amble that the agreement is in four parts, it also says "[f]ollowing is the text of the agreement for the implementation of parts one and two of the above." Confusingly, the following contains headings of Parts One to Three. It is quite short at only four pages.
The summaries of parts one and two mention enforcement mechanisms, but no enforcement mechanisms are described in the body text. No penalties are mentioned if either party fails to abide by the agreement.
The agreement puts an onus on the United States to withdraw all of its forces (and to somehow bring about the withdrawal of all allied and Coalition forces as well), within fifteen months of the signing of the agreement. The agreement was signed on the 29th of February, 2020. This commits the US and allies to have completely withdrawn their forces from Afghan soil by then end of May, 2021 (nearly three months ago). Arguably the US is already in violation of its responsibilities under this agreement.
It also mentions "The ... Taliban commits that its released prisoners will be committed to the responsibilities mentioned in this agreement so that they will not pose a threat to the security of the United States and its allies." Does the Taliban's immediate pressing of released prisoners into service in its forced takeover of the country fit within the terms of the agreement? Quite possibly it is not a violation.
In summarizing part four, it says: "A permanent and comprehensive ceasefire will be an item on the agenda of the intra-Afghan dialogue and negotiations. The participants of intra-Afghan negotiations will discuss the date and modalities of a permanent and comprehensive ceasefire, including joint implementation mechanisms, which will be announced along with the completion and agreement over the future political roadmap of Afghanistan."
Further on in the text, it says "The United States and the Islamic Emirate of Afghanistan which is not recognized by the United
States as a state and is known as the Taliban seek positive relations with each other and expect that the relations between the United States and the new post-settlement Afghan Islamic government as determined by the intra-Afghan dialogue and negotiations will be positive.
"The United States will seek economic cooperation for reconstruction with the new post-settlement Afghan Islamic government as determined by the intra-Afghan dialogue and negotiations, and will not intervene in its internal affairs."
Given that no new settlement between the Taliban and the Afghan government appears to have been sought, with the agreement implying a commitment on their part to seek such a settlement, and given that the Taliban have instead taken Afghanistan by force, can it not be argued that the Taliban are in violation of the agreement? A bilateral agreement such as this puts obligations on both parties, and not just one.
Although, for a master deal maker like Trump claims he is, this is a lousy agreement that puts few explicit obligations on the Taliban, apart from not allowing foreign terrorists who would threaten the United States to operate on Afghan soil. There are no clauses forbidding explicitly the Taliban actions we have seen recently, and nothing beyond the vague commitment to negotiate a settlement with the Afghan government.
There is a contemporaneous joint declaration that the US signed with the Afghan government:
https://www.state.gov/wp-content/uploads/2020/02/02.29.20-US-Afghanistan-Joint-Declaration.pdf
The signing of these agreements was in late February of last year, when my, and much of the rest of the world's, attention was focused on other events.
Quite a few people are wise after the fact, saying that the collapse we witnessed in Afghanistan was inevitable after the signing of Trump's agreement. I don't know about it being inevitable, exactly. I do not know if any of these people were predicting the collapse of the Afghan government, the complete takeover of the country by the Taliban, and the chaotic US and allied withdrawal this summer, before these events happened, were they?