MURPHY, Circuit Judge. Our court has long interpreted the drug-conspiracy statute, 21 U.S.C. § 846, to prohibit two individuals from knowingly reaching an agreement to distribute drugs. See, e.g., United States v. Potter, 927 F.3d 446, 453 (6th Cir. 2019). This conspiracy test could be read to cover every drug transaction between a willing seller and a willing buyer, even those for the buyer’s personal use. After all, the seller has agreed with the buyer to “distribute” drugs between them. Yet we have also long held that a buyer-seller agreement alone does not establish a “conspiracy” under § 846. See, e.g., United States v. Grunsfeld, 558 F.2d 1231, 1235 (6th Cir. 1977). This case requires us to consider the justification for and scope of this “buyer-seller” exception to our otherwise broad reading of the drug-conspiracy statute.

The government presented overwhelming evidence that Aaron Reels operated a drug-distribution scheme. The problem? Reels was not on trial. William Wheat was. And the evidence against Wheat showed essentially that he once gave Reels a .3-gram free “sample” of heroin—a sample that led to no further exchanges between them. The government alleged that Wheat agreed with Reels to distribute heroin, and a jury convicted him of a drug conspiracy. We conclude, however, that insufficient evidence supports this conviction. The logic underlying our buyer-seller exception extends to Wheat’s agreement to distribute a sample to Reels. And the government did not present enough additional evidence of a broader agreement between Wheat and Reels to distribute heroin to third parties. At the same time, Wheat used his phone to arrange the exchange of the sample. So the government more than sufficiently proved that he used a “communication facility” to facilitate a drug felony. 21 U.S.C. § 843(b). We thus reverse Wheat’s conspiracy conviction, affirm his communication-facility conviction, and remand for resentencing.