Is there somewhere that
officially tells them not to? No, not that I have ever seen. It's just a really bad plan. Most of the time, when the physician documents codes in the op note, they are incorrect or missing things. Especially if they also try to add modifiers and dx codes. When it is reviewed and billed by a coder and when records are requested, there is a discrepancy. Providers are at risk of issues, audits, denials, & take backs when the codes in the op note/report don't match what was billed. Further, do they only list a bunch of codes on the report and not actual words for the procedure and the diagnosis? This is also a bad plan. They must use words, not codes to describe what was done. My opinion and suggestion to providers has always been PLEASE
do NOT do this. If they wanted to communicate what they want billed or thought was correct, I had them communicate in a different format with me or their coder/team outside of putting it in the op note. It depends on how your practice is set up whether this would work or not. In my scenario, we had assigned providers and they communicated with their team directly. I cannot tell you how many big cases with multiple procedures had a huge CPT list the provider thought was correct yet the coding was totally different. They mean well, but there are a lot of nuances and bundling, NCCI, etc. that they could not keep up with. They would search for a procedure, a code would pop up, and they would add all of them. When a coder coded it, it might be 2 codes vs. the 7 they put on there.

They also didn't always know what health plan was being billed and the specific rules for some of those.
I know a lot of EMR/EHR have superbill sections or lists embedded into the patient's record/file/account, that's not what I mean. I am talking about when a stand alone note has the codes listed because the provider dictated them or added them to it.
I am not saying providers should not code, they certainly should, I am saying they shouldn't put a list of codes into the legal medical record note like an op note. Your practice or hospital may have written P&P on it, you would want to check that too. You would also want to talk with the compliance and risk department depending on your facility or practice.
Not official but a trusted source:
https://www.kzanow.com/articles/op-note-documentation-tips-every-surgeon-can-use
"The procedures performed are listed in this area of the operative note, which is typically on the top half of the first page. We recommend using CPT terminology as much as possible, but
not including codes in the operative note. Why? Oftentimes, the codes documented in the operative note are not accurate.
It becomes a compliance issue when the codes in the operative report do not match the codes billed on the CMS 1500 claim form. Medicare’s General Principles of Medical Record Documentation state the CPT and ICD-10-CM codes reported on the health insurance claim form or billing statement should be supported by the documentation in the medical record. When a CPT code is documented in the operative report but not billed the CPT code billed is not “supported by the documentation in the medical record” as Medicare requires."
You can infer from this for example if what was listed doesn't match what was billed on the claim:
"Documentation supporting the
diagnosis code(s) required for the item(s) billed
Documentation to support the code(s) and modifier(s) billed"
Old and has old 95/97 E/M info but good concepts:
https://www.facs.org/media/2bajckkl/acs_surgical_note_templates.pdf
Recent with generally good info:
https://libmaneducation.com/operative-documentation/