Opinion by Judge KOZINSKI; Dissent by Judge THOMAS
KOZINSKI, Circuit Judge.Federal law imposes a mandatory minimum sentence for certain crimes, but only if the defendant has a felony drug prior. In order to render defendant eligible for the mandatory minimum, the government must allege the prior conviction in an information pursuant to 21 U.S.C. § 851. We consider what the government must do to comply with this provision.
*942I
The government charged Felix Severino for his role in a conspiracy to distribute cocaine and the related charges of possession and distribution. See 21 U.S.C. §§ 846, 841(a)(1). After Severino and the United States entered into a plea agreement, the district court held a plea hearing in Anchorage, Alaska, with the Assistant United States Attorney appearing by telephone from Fairbanks.
Earlier that day, the prosecutor had filed an information in the Fairbanks federal courthouse alleging that Severino had had a prior felony drug conviction in Massachusetts, for “[possession of 1 ounce to 1 kñogram of cocaine[,] 1992-1993.” Sev-erino was, in fact, convicted in 1992 for felony possession of 1 ounce to 1 kilogram of cocaine, but in Rhode Island, not Massachusetts.
At the change-of-plea hearing, Severi-no’s counsel was the first to raise the topic of prior convictions. He mentioned that Severino had a prior felony drug conviction “back East,” and represented that he (the lawyer) had explained the sentencing consequences of that conviction to his client. Defense counsel also offered that the chances of challenging the validity of the conviction were “zero,” and “really not an issue in the case.”
The prosecutor explained that the expedited timing of the hearing — set to accommodate the vacation schedule of Severino’s attorney' — hadn’t given him a chance to get the information into the hands of the defendant or his counsel before the hearing. He did, however, represent that the information had been filed and summarized its contents. Severino’s counsel enthusiastically confirmed the existence of the prior in the prosecutor’s information (“That’s the one”), and Severino himself acknowledged the prior and the effect it would have on his sentence.
The judge accepted the guilty plea and sentenced Severino to the mandatory minimum of ten years in prison as a result of the prior. Neither at the change-of-plea hearing nor at sentencing did Severino object to the adequacy of the information filed — its substance, the timing or how it was served. Severino acknowledged, not once but three times, that he had a prior felony drug conviction. He said that he understood the sentencing effects of that conviction. And he did not then — nor does he now — suggest any way of challenging it.
Severino did not appeal but he eventually filed a petition pursuant to 28 U.S.C. § 2255.1 Represented by a new lawyer, Severino challenged a number of errors. He made one successful trip to this court, where we vacated his sentence because the district court had failed to inform Severino of his right to appeal. See United States v. Severino, No. 99-35161, 1999 U.S.App. LEXIS 34564, 1999 WL 1278048 (9th Cir. Dec. 30, 1999). On remand, the district court reinstated the original sentence, though reluctantly' — the court recognizing that Severino had made substantial progress in prison, but also noting its lack of discretion.
Severino appealed once again, and a divided panel affirmed on the ground that Severino had waived his rights under section 851(a) and that any deficiency not waived was harmless. See United States v. Severino, 268 F.3d 850 (9th Cir.2001). We subsequently took the case en banc. United States v. Severino, 284 F.3d 985 (9th Cir.2002).
*943II
Section 851 is a procedural statute; the facts and the law either exist to enhance defendant’s sentence or they don’t — section 851(a) doesn’t change that.2 The statute merely “ensures proper notice so a defendant is able to challenge the information [and] make an informed decision about whether or not to plead guilty.” United States v. Hamilton, 208 F.3d 1165, 1168 (9th Cir.), cert. denied, 531 U.S. 867, 121 S.Ct. 164, 148 L.Ed.2d 111 (2000). These procedures take form in four requirements. The information must be in writing; it must be filed with the court and served on the defendant or his counsel; it must be filed and served before trial or before a guilty plea; and the substance of the information must identify the previous conviction(s).
Severino’s principal claim is that the information did not satisfy the requirements of section 851 in two ways: the substance of the information, vague and naming the wrong state, failed to identify the prior conviction used at sentencing; and, even if the information was timely filed, it wasn’t timely served because service must be received, not just mailed, before the plea hearing.
A. The Specificity Requirement
The text of section 851(a) is “silent on the specificity with which the government must identify prior convictions.” United States v. Layne, 192 F.3d 556, 576 (6th Cir.1999). Obviously, the information need not include every known fact about the prior. The government, rather, must include sufficient facts so that a rational defendant can identify the prior conviction and make an informed decision about whether to challenge the substance of the information. See, e.g., id.; Kelly v. United States, 29 F.3d 1107, 1109 (7th Cir.1994), overruled on other grounds by United States v. Ceballos, 302 F.3d 679 (7th Cir.2002). We must consider whether inclusion of some information that inaccurately describes the prior conviction defeats the statutory purpose of giving defendant notice.
We have confronted this question in the similar setting of indictments. Like informations, indictments “provide defendants with the notice necessary to allow them to challenge the contents” of the charge. United States v. Steen, 55 F.3d 1022, 1026 (5th Cir.1995). We have found indictments legally sufficient if, as a whole, they “adequately apprised the defendant of the charges against him.” United States v. James, 980 F.2d 1314, 1316 (9th Cir.1992). Because a defendant can be put on notice of a charge despite certain mistakes, “‘minor or technical defieiencpes] in the indictment’ ” will not reverse a conviction if there is no prejudice. Id. (quoting United States v. Normandeau, 800 F.2d 953, 958 (9th Cir.1986), overruled in part on other grounds by United States v. Nordby, 225 F.3d 1053 (9th Cir.2000)); see also Fed.R.Crim.P. 7(c)(3). Only where defendant is misled to his prejudice about the charges against him will we find an indictment inadequate.
We adopt the same approach in testing the sufficiency of a section 851(a) information: If the defendant, reading the information in context, will have no trouble understanding which prior conviction the *944prosecutor means to identify, the information then has “stat[ed] ... the previous convictions,” and the statutory purpose of providing defendant notice has been satisfied. Like the Fifth Circuit, we hold that errors in an information “negate[ ] the notice provided by the other listed data only if the discrepancy misled [the defendant] to his prejudice.” Steen, 55 F.3d at 1028.
Other circuits have reached the same conclusion, allowing errors if the information, despite its mistakes, still definitively identified the prior conviction. Informa-tions under section 851(a) have been deemed sufficient despite the fact that they contained the wrong date, see United States v. King, 127 F.3d 483, 489 (6th Cir.1997), the wrong offense, see Steen, 55 F.3d at 1025-28, and the wrong statutory section, see United States v. Campbell, 980 F.2d 245, 251-52 (4th Cir.1992), and even though the description of the prior was quite sketchy, see United States v. Gonzalez-Lerma, 14 F.3d 1479, 1485-86 (10th Cir.1994) (no docket number, specific location or correct date). Section 851(a) was satisfied in each of these cases because the information gave the defendant fair notice of which prior conviction the government had in mind for seeking a sentence enhancement. See, e.g., Steen, 55 F.3d at 1026-27.
This is already the law in our circuit. In Hamilton, we “addressed the substantive requirements of an information under section 851(a).” 208 F.3d at 1168. Careful not to “ ‘elevat[e] form over substance,’ ” id. (quoting King, 127 F.3d at 489), we held that “[a]s long as the information provides clear notice to a defendant of the prior convictions (and the court gives an opportunity to attack [such] convictions ...), then the statute has been satisfied.” Id. at 1169. Applying that standard, Hamilton held that an information that misstates the date of conviction by five years can nonetheless satisfy section 851: Given the context, the defendant in Hamilton “could not have been confused about the prior conviction” and therefore had “sufficient notice that the government was aware of his prior conviction and would seek to enhance his sentence.” Id. at 1168-69.
The clerical error provision,3 which allows the government to correct “clerical mistakes” in an information before sentencing, does not raise the inference that no other mistakes are permitted. The contrary view has been implicitly rejected by the circuits (including ours) that have found compliance with section 851(a) despite a number of non-clerical errors. See p. 944 supra. Nor is the clerical error provision, in fact, inconsistent with our analysis. The provision functions as a safe harbor for certain minor errors. If the error is deemed to be clerical, the government may simply correct it by filing an amended information without showing that defendant was not misled. If the error is non-clerical, however, the information is deemed defective unless the government shows that defendant could not reasonably have been misled to his prejudice as to the identity of the prior conviction.
Here, the information left no doubt about which prior conviction the government had in mind as the predicate for the sentence enhancement. The defendant has a prior drug conviction — a single prior drug conviction. The information correctly identified the crime (possession), the type of drug (cocaine), the quantity (1 ounce to 1 kilogram) and the year of conviction (1992-1993). It did err as to the state, but the error was no more serious than the five-year discrepancy we allowed *945in Hamilton; it could not possibly have put Severino in doubt about which one of his prior convictions the government was referencing in the information. Indeed, Severino’s counsel agreed that the information, as stated, was correct (“That’s the one I was referring to when I said back East, Your Honor.”). Severino himself agreed that the information was correct. Severino’s counsel even volunteered that Severino’s prior would “kick up [the sentence] to that mandatory 10 years.” Sev-erino, too, acknowledged that his prior would result in a 10-year minimum. In fact, he acknowledged it more than once. And he did not, and does not, suggest that he has any way to challenge its validity.
All told, Severino cannot reasonably assert that he was blindsided by the government. Nor can Severino reasonably assert that he entered his plea expecting anything less than a 10-year mandatory minimum sentence. The information put all parties' — as clearly acknowledged during the plea hearing — on the same page. “It is inconceivable that [Severino] would have presented a different defense if the [information] had been corrected.” James, 980 F.2d at 1319. Because the information, in light of the context, adequately identified Severino’s prior conviction, it complied with the requirements of section 851(a), and with due process as well. See Gonzalez-Lerma, 14 F.3d at 1485.
B. The Service Requirement
Section 851(a) requires that the information be filed and served before trial or the plea hearing. The statute does not define service. However, Fed.R.Crim.P. 49(b) generally defines service in criminal cases. We presume that Congress is aware of this provision and means to incorporate it by reference when it provides for service but does not specify the means. See Lorillard v. Pons, 434 U.S. 575, 583, 98 S.Ct. 866, 55 L.Ed.2d 40 (1978) (“ ‘[W]here words are employed in a statute which had at the time a well-known meaning at common law or in the law of this country they are presumed to have been used in that sense unless the context compels to the contrary.’ ”) (quoting Standard Oil Co. v. United States, 221 U.S. 1, 59, 31 S.Ct. 502, 55 L.Ed. 619 (1911)); see also Neder v. United States, 527 U.S. 1, 21, 119 S.Ct. 1827, 144 L.Ed.2d 35 (1999) (noting that where Congress uses terms with settled meanings, “a court must infer, unless the statute otherwise dictates, that Congress means to incorporate the established meaning of these terms” (internal quotation marks omitted)).
Rule 49(b) provides that service “shall be made in the manner provided in civil actions,” which, in turn, declares that, “[s]ervice by mail is complete on mailing.” Fed.R.Civ.P. 5(b)(2)(B) (emphasis added). Because Congress has defined what it means by service, we have no authority to require more. In fact, to do so here would create a conflict with the two other circuits that have confronted the question and held that, to satisfy section 851(a)’s service requirement, the government need only show that it “mailed the information to [defense] counsel, and not that defense counsel actually received [it].” United States v. Kennedy, 133 F.3d 53, 59 (D.C.Cir.1998); see also United States v. White, 980 F.2d 836, 840 n. 8 (2d Cir.1992) (holding that section 851 is satisfied even where defendant received service after trial began, so long as service was mailed before trial).
Here, the government attached a certificate of service to its original information; Severino does not contest that both documents were filed before the start of the plea hearing. The person who signed the certificate of service stated under oath that he mailed a copy of the information to defense counsel prior to filing. Severino questions whether the in*946formation was in fact mailed before the hearing, but offers no evidence casting doubt on the government’s certificate. The certificate thus remains the only evidence in the record of when the served copy was mailed to the defendant. Had Severino offered evidence that contested the declaration in the certificate of service, he may have been entitled to an evidentia-ry hearing on this point, but he did not. The unchallenged certificate is therefore sufficient to establish that the information was placed in the mail prior to the hearing.
In any event, Severino’s principal contention is that service isn’t complete when the document is mailed. If the purpose of the statute is to provide notice, Severino argues, then it doesn’t make much sense to have the document reach him after it’s too late to do him any good. Congress therefore must have intended that service is not complete until defendant actually receives it.
This argument proves too much. The possibility that a mailed document may not reach the intended recipient until it’s too late is not unique to our situation; it arises whenever a document is served by mail. The party being served will not benefit from the service if the document is mailed too close to the date of the hearing to which it pertains, is delayed in transit or is lost altogether. Even if the document does reach the opposing party before the hearing, it may nonetheless get there too late to give the recipient sufficient time to prepare a response. Rule 49(b) nevertheless specifies that service by mail is complete upon mailing. Obviously, the service requirement is designed to provide timely notice in ordinary circumstances, but not to guarantee adequate notice in every case.4
To be sure, when the statutory requirement of service is satisfied, this does not always mean that the independent constitutional requirement of adequate notice has been satisfied as well. In most instances the two will coincide but, where they do not, the party who was properly served yet received inadequate notice (such as where the document is lost in the mail) will be entitled to an accommodation to make up for any prejudice resulting from the failure of notice.
Here, the statutory requirement of service was satisfied when a copy of the information was placed in the mail prior to the hearing. Obviously, this was too late to give Severino advance notice of its contents, much less time for him and his lawyer to prepare a challenge to the offense changed therein. Indeed, had Severino and his counsel been unaware of the possibility that the prior conviction would be raised as an enhancement, even physical service by fax or messenger on the morning of the plea hearing may still have provided inadequate notice. But Severino and his counsel were well aware of the drug prior, and were fully expecting to have it raised at the change-of-plea hearing. They had obviously discussed the *947matter before the hearing and concluded that there was no legitimate way to challenge the conviction. Moreover, the Assistant United States Attorney recited the substance of the information over the phone at the hearing. Had Severino or his counsel then raised an objection to proceeding with the change-of-plea hearing because of inadequate notice, they would probably have been entitled to a postponement. But Severino and his lawyer did the precise opposite: They made it quite clear they were aware of the issue, they were not surprised in any way and had had adequate time to consider what to do about it. They did not ask for a continuance, or even a recess, to discuss the matter. We must therefore conclude that notice was adequate and, because service was completed before the hearing in accordance with Rule 49(b), the statutory requirement of service was satisfied as well.5
III
A. Severino correctly points out that the district court erred by failing to ask him if he affirmed or denied his previous conviction, and by failing to “inform him that any challenge to a prior conviction which is not made before sentence is imposed may not thereafter be raised to attack the sentence.” 21 U.S.C. § 851(b).6 Because Severino did not object, we consider whether the error affected his “substantial rights.” See United States v. Olano, 507 U.S. 725, 734-35, 113 S.Ct. 1770, 123 L.Ed.2d 508 (1993); see also Fed. R.Crim.P. 52(b).7
The Supreme Court has made clear that the default rule — assumed unless the statute expressly provides otherwise — is that rights can be waived, both in the affirmative sense (explicit waiver) and by , failing to object to error (default or forfeiture). As Olano held, “No procedural principle is more familiar to this Court than that a constitutional right, or a right of any sort, may be forfeited in criminal as well as civil cases ....” 507 U.S. at 731, 113 S.Ct. 1770 (quoting Yakus v. United States, 321 U.S. 414, 444, 64 S.Ct. 660, 88 L.Ed. 834 (1944) (internal quotation marks omitted)); cf. United States v. Mezzanatto, 513 U.S. 196, 201, 115 S.Ct. 797, 130 L.Ed.2d 697 (1995) (“[A]bsent some affirmative indication of Congress’ intent to preclude waiver, we have presumed that statutory provisions are subject to waiver.”). It follows that harmless error review is presumed to apply. See Jones v. United States, 527 U.S. 373, 388-89, 119 S.Ct. 2090, 144 L.Ed.2d *948370 (1999) (applying default forfeiture rules where the statute does not “explicitly announce an exception to plain-error review”); Olano, 507 U.S. at 731, 113 S.Ct. 1770. Even those courts holding that section 851(a)’s requirements are “jurisdictional” accept that harmless error doctrine applies to section 851(b). See, e.g., United States v. Gonzalez-Lerma, 71 F.3d 1537, 1540-41 & n. 4 (10th Cir.1995) (Gonzalez-Lerma II).
Here, Severino admitted — more than once — that he had no way to challenge the validity of the prior conviction. He walked into the plea agreement voluntarily, aware that he was almost certainly going to be subject to a mandatory minimum on account of the prior. Severino cannot plausibly argue that he would have done anything differently, had the district court properly asked him to affirm or deny the prior conviction, or had the district court informed him that he would lose the right to challenge that conviction upon accepting the plea. The error was harmless.
B. Finally, Severino claims that he was prejudiced by his counsel’s failure to object to the adequacy of the information. Such a claim — in reality a charge that counsel was ineffective — is usually better reserved for collateral review, where the facts and record can be appropriately developed. See United States v. Karterman, 60 F.3d 576, 579 (9th Cir.1995). On these facts, however, we can at least say this: Because we hold that the information satisfied section 851(a), Severino’s ineffective assistance claim, to the extent that it relies on counsel’s failure to object to the information, necessarily fails: There can be no error in failing to object to an adequate information. Other claims of ineffective assistance we leave for possible exploration in a future petition for collateral review.8
AFFIRMED.
. By failing to appeal his sentence, Severino might have been deemed to have defaulted these claims. In an earlier appeal, however, we held that the government waived this argument by failing to raise it. See United States v. Severino, No. 99-35161, 1999 U.S.App. LEXIS 34564, at *2 n. 3, 1999 WL 1278048 (9th Cir. Dec. 30, 1999).
. Section 851(a) provides in relevant part:
No person who stands convicted of an offense under [21 U.S.C. §§ 841 et seq.] shall be sentenced to increased punishment by reason of one or more prior convictions, unless before trial, or before entry of a plea of guilty, the United States attorney files an information with the court (and serves a copy of such information on the person or counsel for the person) stating in writing the previous convictions to be relied upon.
. "Clerical mistakes in the information may be amended at any time prior to the pronouncement of sentence.” 21 U.S.C. § 851(a)(1).
. No doubt, the rule that service is complete upon mailing is based in large part on considerations of administrative convenience. A party must file a certificate of service at the time it files the served document, and it is fairly easy to certify that service has been completed by placing a copy thereof in the mail. It would be a far more difficult matter to certify service if it were complete only upon receipt. Service by mail would then become virtually impossible because the sending party would seldom be able to declare under oath that a document has been received by the opposing party. Most routine documents would have to be served by personal courier and, even then, could not be filed until and unless the process server confirms that the document had actually been received. The drafters of Rule 49(b) no doubt believed that the additional benefit from requiring actual receipt wasn't worth the additional inconvenience.
. We need not decide whether a section 851(a) error can be waived or forfeited by a defendant, so it remains an open question in our circuit. Hamilton required strict compliance to satisfy the statute, but said nothing about waiver or forfeiture, as the defendant there actually objected to the adequacy of the government’s information, and we found that the information complied with the statute. See 208 F.3d at 1167-69.
. Severino preserved this issue by raising it in his first appeal; we didn't address it at that time because we vacated his sentence on other grounds. See Severino, 1999 U.S.App. LEXIS 34564, at *3.
. It’s a bit strange to require that a defendant object to the district court’s failure to give him an admonition. After all, if the defendant knows to object, he doesn’t need the admonition in the first place; it’s the defendant who fails to object that needs the admonition most. Nevertheless, we feel bound by United States v. Vonn, 535 U.S. 55, 122 S.Ct. 1043, 152 L.Ed.2d 90 (2002), where the Supreme Court rejected the same argument in the Rule 11 context. See 122 S.Ct. at 1054 n. 10 (noting that it is, “fair to burden the defendant with his lawyer’s obligation” to understand and object to failings in the admonition, and that although "an uncounseled defendant may not, in fact, know enough to spot a Rule 11 error, ... when a defendant chooses self-representation after a warning from the court of the perils this entails, Rule 11 silence is one of the perils he assumes” (citation omitted)).
. Severino may have waived these claims by failing to raise them in his first 2255 petition, where his claim of ineffective assistance was limited to a claim that counsel had failed to advise him of his right to appeal the sentence. We leave this question for another day.