The phrase "agreement as proof" is correct and usable in written English.
It can be used in contexts where a formal agreement is being referenced as evidence or validation of a claim or situation.
Example: "The signed contract serves as an agreement as proof of the terms we discussed."
Alternatives: "contract as evidence" or "agreement as evidence".
Barack Obama hailed completion of the nuclear agreement as proof of what "smart, patient and disciplined" diplomacy can achieve.
The rest of the world hailed the Oslo agreement as proof that the Israeli-Palestinian conflict could be resolved.
If your Gas and/or Electric services are off, or if you are moving or transferring services from one address to another, you must provide a current lease agreement as proof that you reside at the address.
This is difficult for people living in informal housing or rural areas, who rarely have utility bills or lease agreements as proof.
Indeed, foreign human-rights monitoring groups give warning that China's government often points to the existence of such paper agreements as proof of progress, even as it brazenly flouts their terms.
Republican leaders hailed the agreements as proof that they were finally getting a handle on the federal budget after a five-year binge of new spending and tax cuts that turned record budget surpluses into a stream of massive deficits.
Government strategy appears to be to collect irrelevant aboriginal names on pipeline agreements as proof that communities "consent" to pipeline construction.
The government's strategy appears to be to collect irrelevant aboriginal names on pipeline agreements as proof that communities "consent" to construction projects.
In this courtroom, sometime ago, a film was shown in which a speech I made for the newsreels of that time, at the conclusion of this naval agreement, was presented as proof of the duplicity of German diplomacy.
A commentary in China's state-run Xinhua news service shrugged off Western concerns and cast the new agreement with Italy as proof of the BRI's ability to benefit local populations and serve as a "win-win" for all parties.
Think abstractly about a social/economic/international policy approach that is unaccountable to data, one that sees doubt as weakness, agreement among insiders as proof, and change as bad.
