TORRUELLA, Circuit Judge.

Facing a five count indictment on narcotics and firearm charges, Jorge Rivera-López ("Rivera") entered into a plea agreement containing a waiver-of-appeal provision. Pursuant to that agreement, he was sentenced to sixty months of imprisonment and a five-year term of supervised release. For the first six months of his supervised release, Rivera's sentence also included a nighttime curfew and twenty-four-hour electronic monitoring. He now seeks to appeal these two conditions of supervised release, arguing that their imposition amounts to a miscarriage of justice. Upon review, we find that Rivera's appellate waiver extends to the contested conditions and, consequently, dismiss his appeal.

I. Background

In August 2012, Puerto Rico Police Department officers executed a search warrant of an apartment in which Rivera was sleeping. Inside, the officers found two firearms and multiple controlled substances. An indictment followed, charging Rivera and his two co-defendants each with four counts of possession with intent to distribute controlled substances, in violation of 21 U.S.C. § 841(a)(1), and one count of possession of a firearm in furtherance of a drug crime, in violation of 18 U.S.C. § 924(c)(1)(A)(i-ii).

Rivera subsequently entered into a plea agreement, admitting guilt as to the firearms charge. In exchange for this guilty plea, the government recommended that all four counts of narcotics possession be dismissed and that Rivera be sentenced to a term of sixty months of imprisonment. Under a provision titled "Maximum Penalties," the agreement made clear that Rivera faced "a minimum term of imprisonment of five [] years and a maximum term of life in prison" as well as "a supervised release term of not more than five [] years." Another provision, titled "Waiver of Appeal," stated that Rivera would not seek appellate review of any "judgment and sentence" that was in accordance with the agreement's terms and recommendations.

The district court imposed the recommended term of sixty months of imprisonment as well as a five-year term of supervised release. For the first six months of supervised release, the court further required Rivera to comply with curfew and electronic monitoring conditions:

Rivera objected at sentencing, arguing that the conditions were insufficiently related to the crime charged and inconsistent with the sentences of his co-defendants, which did not include curfew or electronic monitoring conditions. The district court judge responded that "[i]n my courtroom, all gun cases receive [these] condition[s]."

Rivera now seeks to appeal these same conditions, reasserting his objections below. Acknowledging that his waiver-of-appeal was knowing and voluntary, he nonetheless asks this court to vacate the conditions so as to avoid a miscarriage of justice.

II. Discussion

Where knowing and voluntary, an appellate waiver is generally enforceable, absent indications that such a waiver would work a "miscarriage of justice." United States v. Teeter, 257 F.3d 14, 25 (1st Cir.2001). We have declined to strictly delineate the boundaries of this miscarriage-of-justice exception, choosing instead to review claims wholesale, with an eye to the "character, clarity, and gravity of the claim of error." United States v. Nguyen, 618 F.3d 72, 75 (1st Cir.2010) (recognizing that "[t]he circumstances potentially justifying a refusal to enforce a waiver on this ground are `infinitely variable'" (quoting Teeter, 257 F.3d at 25 n. 9)). What is clear, however, is that the exception is to "be applied sparingly and without undue generosity"; mere "garden-variety" claims of error are insufficient to sustain an appeal in the face of waiver. Teeter, 257 F.3d at 26; see also United States v. Miliano, 480 F.3d 605, 608 (1st Cir.2007) (requiring, to overcome an appellate waiver, "an increment of error more glaring than routine reversible error").

Rivera readily concedes that his decision to enter into the plea agreement, including the waiver of appeal, was both knowing and voluntary. He also admits that the district court made sure he understood the nature of this waiver. Therefore, we take up only the limited question of whether the contested conditions amount to a miscarriage of justice. See Nguyen, 618 F.3d at 75.

Sentencing judges have broad discretion to impose conditions of release so long as they are "reasonably related" to (1) the underlying offense or character and criminal history of the defendant; (2) the need to deter criminal conduct; (3) the goal of protecting the public; or (4) the provision of rehabilitative educational, health, or other treatment for the defendant. U.S.S.G. § 5D1.3(b); see also 18 U.S.C. § 3583(d); United States v. Brown, 235 F.3d 2, 6 (1st Cir.2000) ("[T]he critical test is whether the challenged condition is sufficiently related to one or more of the permissible goals of supervised release."). Such conditions must also "involve no greater deprivation of liberty than is reasonably necessary." U.S.S.G. § 5D1.3(b); see also 18 U.S.C. § 3583(d)(2).

Rivera's argument is twofold. First, that the imposition of the curfew and electronic monitoring conditions circumscribes his liberty to a greater extent than necessary or appropriate. Second, that the district court lacked any reasoned basis for these conditions, as illustrated by the inconsistent sentences of Rivera's co-defendants and the overly broad statement that "all gun cases" are subject to the same. In combination, he asserts that these errors are of such significance that allowing his appellate waiver to stand would shield from our review a miscarriage of justice.

As an initial matter, the co-defendants' sentences are not before us on this appeal, and therefore we decline to speculate as to why the same conditions were not imposed on those individuals. When "identically situated defendants" receive significantly disparate sentences, red flags may indeed be raised. United States v. Mueffelman, 470 F.3d 33, 41 (1st Cir.2006). Where supported by reason, however, the mere existence of a disparity in sentencing between co-defendants in no way necessitates a finding of error. See, e.g., United States v. Marceau, 554 F.3d 24, 33-34 (1st Cir.2009). Certainly, no such finding is required here, as Rivera did not even attempt to substantiate his miscarriage-of-justice claim with proof that he and his co-defendants were, in fact, identically situated. Therefore, we focus our review only on whether the conditions of Rivera's supervised release were so lacking in rationality or so wholly unrelated to legitimate sentencing purposes as to necessitate invalidating his waiver of appeal.

Even setting aside the district court's proffered explanation that "all gun cases" receive the special conditions in question,2 the record suggests an alternative basis for their imposition in Rivera's case. See United States v. Garrasteguy, 559 F.3d 34, 42 (1st Cir.2009) ("[The] requirement [that conditions be supported] can be satisfied without a written or oral explanation . . . if we can infer the court's reasoning by comparing what was argued by the parties or contained in the pre-sentence report with what the court did.") (citing United States v. Jiménez-Beltre, 440 F.3d 514, 519 (1st Cir.2006) (en banc)). At sentencing, Rivera presented his long history of significant substance abuse, failed treatment attempts, and suicidality as factors in support of mitigation. He also requested that the district court recommend him for participation in an appropriate drug treatment program and receipt of mental health care while incarcerated. In light of Rivera's choice to draw the court's attention to his history of drug abuse and failed treatment attempts, the curfew and electronic monitoring conditions can be understood as efforts to assist in his rehabilitation.

Because of the waiver of appeal at play in this case, see Miliano, 480 F.3d at 608 (requiring more than reversible error to sustain a finding of a miscarriage of justice), we need not plumb the exact contours of a court's ability to impose such special conditions. In fact, we explicitly decline to suggest that such conditions, if squarely before us on appeal, would necessarily be found appropriate, as we can easily conceive of instances where past substance abuse is so unrelated to the crime charged or separated by a sufficient passage of time as to make these conditions unwarranted. See Brown, 235 F.3d at 7 ("The hallmark that separates impermissible conditions from permissible ones is whether, on a given set of facts, a particular restriction is clearly unnecessary.").

As to the much simpler question of whether the conditions are so clearly erroneous and unsubstantiated as to work a miscarriage of justice, however, the answer is clear. They are not. The miscarriage-of-justice standard is a steep obstacle for potential appellants to overcome, see Teeter, 257 F.3d at 26, and Rivera's history of drug abuse, charged conduct, and request for treatment makes clear that the contested conditions are sufficiently related to legitimate goals of sentencing as to fall within the auspices of his waiver of appeal. Cf. Nguyen, 618 F.3d at 76 (finding a condition of supervised release warranted, and thus necessarily insufficient to overcome a waiver of appeal). Thus, we hold that Rivera's knowing and voluntary waiver of appeal bars his instant challenge.

III. Conclusion

For the reasons stated herein, Rivera's appeal is dismissed.

Dismissed.