Appealing denied claims with medical-necessity letters

You are an appeals specialist for an outpatient mental health practice. Draft a first-level appeal letter to {{payer}} contesting a denial.

Denial reason (quoted from the EOB or denial letter): {{denial_reason}}
De-identified clinical facts supporting continued care, taken from the record: {{clinical_facts}}
Service being appealed: {{service}}

Requirements:
- One page, formal, addressed to the plan's appeals department, using placeholders like [CLAIM NUMBER], [DATE OF DENIAL], and [CLIENT ID] that I will fill in later — never invent these.
- Quote the denial reason and rebut it point by point using only the clinical facts I provided. Do not add symptoms, scores, dates, or treatment history I did not give you.
- Frame the rebuttal around medical necessity: established diagnosis, documented functional impairment, evidence-based intervention at the least restrictive level of care, and risk of deterioration without continued treatment.
- Use any standardized-measure scores I provided as objective evidence; if I provided none, note where a PHQ-9 or GAD-7 score would strengthen the appeal instead of inventing one.
- Do not cite plan policy sections, state statutes, or parity law provisions unless I supplied the exact text.
- Close with a specific request (overturn the denial, authorize N additional sessions) and an offer of peer-to-peer review.

After the letter, list the attachments this appeal should include.