Is a defense counsel's opinion relevant in determining whether there is substantial evidence of incompetency?

Because a court must "consider all of the relevant circumstances" in determining whether there is substantial evidence of incompetency, defense "counsel's opinion is undoubtedly relevant." (People v. Howard (1992) 1 Cal.4th 1132, 1164; Drope, supra, 420 U.S. at p. 177, fn. 13 [defense counsel is person with " 'closest contact with the defendant[;]' " thus, her opinion "is unquestionably a factor which should be considered"].) However, "[t]he opinion of counsel, without a statement of specific reasons supporting that opinion, does not constitute substantial evidence." (Cal. Rules of Court, rule 4.130(b)(2).)