Appeal letter builder

Example conversation

You: The Anthem denial for the L4-L5 fusion on case 2026-0412-88174 is normalized. Draft the appeal letter.

Agent: Reading case.json. Branch is clinical-appeal, appeal level 1st-internal, categories ["not-medically-necessary", "lack-of-prior-auth"], CPT 22633 + 22840, ICD-10 M51.16 + M48.06. LOMN is at drafts/lomn-2026-0412-88174.md. Payer policy excerpt on file names gabapentin, duloxetine, and a 12-week PT + ESI trial as the step-therapy path before surgical consideration.

Agent: Assembling the appeal record. Header addressed to Anthem Clinical Appeals (PO BOX 5063, Middletown NY); RE line populated with member ID YRK8827461, DOB 1968-05-14, claim C-9918274461, denial date 2026-04-12, payer reference CA-2026-0412-88174. Introduction names this as a Level 1 internal appeal and quotes both denial phrases.

Agent: Running denial_reason_rebuttal_checker with the verbatim denial text and categories. Result: not-medically-necessary matched via phrase “medical necessity under the plan’s definition”; lack-of-prior-auth matched via phrase “retroactive authorization is appropriate here because”. ok: true.

Agent: Running preferred_therapy_argument_generator with plan_preferred_agents: ["gabapentin", "duloxetine", "physical therapy", "epidural steroid injection"]. All four matched the prior-therapy history: gabapentin 900 mg TID x 12 weeks (no functional improvement, somnolence), duloxetine 60 mg QD x 8 weeks (discontinued for intolerable nausea), PT 2x/week x 14 weeks (no change in ODI), right L4-L5 transforaminal ESI 2026-01-18 (< 2 weeks relief). unaddressed: [].

Agent: Running contradiction_checker. One error: rule-6-drg-no-level-of-care-criteria is not tripped (level-of-care is not on this denial), but rule-3-therapy-rationale-mismatch is flagged — my current rebuttal paragraph for not-medically-necessary reads as generic medical-necessity prose and does not reference “posterior lumbar fusion” or the specific anatomy. Returning isError: true. Suggest rewriting the rebuttal to name the requested procedure and cite the conservative-care failures explicitly.

You: Right — fix that. And keep the rebuttal tight; the reviewer will see the LOMN for the full narrative.

Agent: Rewrote the not-medically-necessary block to name “posterior lumbar fusion with instrumentation at L4-L5” and to cite the four failed conservative measures by name with durations and outcomes. Re-ran denial_reason_rebuttal_checker and contradiction_checker; both clean.

Agent: Running appeal_completeness_check on the assembled record. ok: true, 0 missing, 1 warning (enclosures list did not include a copy of the denial letter — I added it). Handing the draft to clinical-claim-evidence-mapper: clinical_claim_extract_candidates returned 9 candidate claims (1 diagnosis, 4 prior therapies, 1 imaging, 1 score (ODI 56%), 1 guideline — NASS 2024 — and 1 outcome). Citing each one now.

Agent: clinical_claim_check_draft returned export_ready: true, 9/9 cited, 0 orphans. Rendering the letter to drafts/appeal-2026-0412-88174.md and appending the claim-to-source index. Audit log entry written.

Sample output excerpt

The skill produces two artifacts: the normalized appeal-letter record the validators run against, and the rendered appeal letter at ./drafts/appeal-{case_id}.md. Excerpts from the Anthem L4-L5 fusion case after the conversation above.

{
  "case_id": "8f3c2a1e-4b9d-4f7c-9e1a-2b6d8c4f1a7b",
  "appeal_level": "1st-internal",
  "appeal_kind": "medical-necessity",
  "header": {
    "provider": {
      "name": "Mountain Ridge Orthopedics",
      "npi": "1659321488",
      "phone": "(208) 555-0144",
      "fax": "(208) 555-0145",
      "address": "500 Alpine Way, Boise, ID 83702"
    },
    "payer": {
      "name": "Anthem Blue Cross Blue Shield",
      "plan": "Anthem PPO",
      "appeals_address": "Anthem Clinical Appeals, PO BOX 5063, Middletown, NY 10940",
      "appeals_fax": "(877) 278-2163"
    },
    "date_of_letter": "2026-04-21"
  },
  "re_line": {
    "member_name": "Jane D.",
    "member_id": "YRK8827461",
    "dob": "1968-05-14",
    "claim_number": "C-9918274461",
    "auth_number": null,
    "dates_of_service": ["2026-03-28", "2026-03-31"],
    "denial_date": "2026-04-12",
    "payer_reference_number": "CA-2026-0412-88174"
  },
  "denial_categories": ["not-medically-necessary", "lack-of-prior-auth"],
  "denial_reason_rebuttal": [
    {
      "denial_category": "not-medically-necessary",
      "denial_phrase_quoted": "does not meet InterQual criteria for surgical intervention",
      "rebuttal_text": "Posterior lumbar fusion with instrumentation at L4-L5 is medically necessary under the plan's definition after documented failure of 12 weeks of gabapentin at 900 mg TID, 8 weeks of duloxetine at 60 mg QD (discontinued for intolerable nausea), 14 weeks of physical therapy with no change in ODI, and a right L4-L5 transforaminal epidural steroid injection on 2026-01-18 with less than two weeks of relief. NASS 2024 coverage criteria for lumbar fusion are met; full clinical reasoning is in the enclosed letter of medical necessity.",
      "supporting_references": [
        { "kind": "lomn-section", "locator": "Section 3: Conservative care trial" },
        { "kind": "guideline", "locator": "NASS 2024 — Lumbar Fusion Coverage Criteria" }
      ]
    },
    {
      "denial_category": "lack-of-prior-auth",
      "denial_phrase_quoted": "prior authorization was not obtained",
      "rebuttal_text": "Retroactive authorization is appropriate here because the service was admitted emergently on 2026-03-28 for acute radiculopathy with progressive foot drop (MRC 3/5 right EHL), and Anthem's Provider Manual §7.4.2 permits retroactive-auth requests within 72 hours for urgent admissions. Documentation of the emergent presentation is included as Enclosure C.",
      "supporting_references": [
        { "kind": "policy", "locator": "Anthem Provider Manual §7.4.2" },
        { "kind": "chart", "locator": "ED note 2026-03-28 14:11" }
      ]
    }
  ],
  "requested_resolution": "Overturn the denial and approve the inpatient admission (2026-03-28 to 2026-03-31) and CPT 22633 with 22840 for posterior lumbar fusion at L4-L5; issue retroactive authorization consistent with Anthem Provider Manual §7.4.2.",
  "enclosures": [
    { "label": "Letter of medical necessity", "doc_path": "drafts/lomn-2026-0412-88174.md" },
    { "label": "Denial letter (Anthem, 2026-04-12)", "doc_path": "denials/anthem_20260412.pdf" },
    { "label": "MRI lumbar spine 2026-02-03", "doc_path": "inputs/mri-2026-02-03.pdf" },
    { "label": "PT evaluation 2026-03-10 (ODI 56%)", "doc_path": "inputs/pt-eval-2026-03-10.pdf" },
    { "label": "ED note 2026-03-28 (emergent admission)", "doc_path": "inputs/ed-note-2026-03-28.pdf" }
  ]
}

Rendered appeal letter excerpt (drafts/appeal-2026-0412-88174.md):

Mountain Ridge Orthopedics
500 Alpine Way, Boise, ID 83702
NPI 1659321488 | Phone (208) 555-0144 | Fax (208) 555-0145

2026-04-21

Anthem Clinical Appeals
PO BOX 5063
Middletown, NY 10940
Fax: (877) 278-2163

**RE: Level 1 internal appeal — medical-necessity + retroactive-authorization**
Member: Jane D. | Member ID: YRK8827461 | DOB: 1968-05-14
Claim: C-9918274461 | Dates of service: 2026-03-28 to 2026-03-31
Denial date: 2026-04-12 | Payer reference: CA-2026-0412-88174

Dear Medical Director,

This letter is a Level 1 internal appeal of Anthem's 2026-04-12 adverse benefit
determination (reference CA-2026-0412-88174), which denied coverage for
posterior lumbar fusion at L4-L5 (CPT 22633, 22840) on the grounds that the
service "does not meet InterQual criteria for surgical intervention" and that
"prior authorization was not obtained." Both grounds are addressed below.

**1. Not medically necessary.** Posterior lumbar fusion with instrumentation at
L4-L5 is medically necessary under the plan's own definition. The patient
completed and failed, in sequence: gabapentin 900 mg TID over 12 weeks with no
reduction in VAS or ODI and persistent daytime somnolence; duloxetine 60 mg QD
over 8 weeks, discontinued for intolerable nausea; supervised physical therapy
2x/week over 14 weeks with no change in ODI (56% on 2026-03-10, severe
disability); and a right L4-L5 transforaminal epidural steroid injection on
2026-01-18 with less than two weeks of relief. MRI dated 2026-02-03 demonstrates
L4-L5 disc extrusion with right S1 nerve-root impingement. These facts satisfy
the NASS 2024 Lumbar Fusion Coverage Criteria; the enclosed letter of medical
necessity carries the full clinical reasoning.

**2. Lack of prior authorization.** Retroactive authorization is appropriate
here. The patient was admitted emergently on 2026-03-28 for acute radiculopathy
with progressive right-sided foot drop (MRC 3/5 right EHL). Anthem's Provider
Manual §7.4.2 permits retroactive-auth requests within 72 hours for urgent
admissions; the ED note from 2026-03-28 14:11 (Enclosure C) documents the
emergent presentation.

**Requested resolution.** Overturn the denial and approve the inpatient
admission (2026-03-28 to 2026-03-31) and CPT 22633 with 22840; issue a
retroactive authorization consistent with Anthem Provider Manual §7.4.2.

Sincerely,

[Signature]
Priya N. Shah, MD
NPI 1487220913 | Board-certified, Orthopedic Surgery
Phone (208) 555-0144

**Enclosures:** Letter of medical necessity; denial letter (Anthem 2026-04-12);
MRI lumbar spine 2026-02-03; PT evaluation 2026-03-10; ED note 2026-03-28;
claim-to-source index.

Extension tools and validations

The skill registers four deterministic validators. All run against the normalized appeal-letter record; none draft prose — the LLM renders sentences and the validators gate export.

denial_reason_rebuttal_checker

• Inputs: denial_reason_text (verbatim from the denial letter), denial_categories (from denial_classifier), draft_text (the rendered letter or the concatenated rebuttal sections).
• What it checks: splits the denial-reason text into phrases, drops boilerplate tokens, and for each phrase searches the draft by direct substring and by 2-of-N keyword overlap within a 200-character window. Independently, for each denial category it searches the draft for at least one category-specific anchor token (e.g., interqual, mcg, lsip, level of care for drg-level-of-care; prior authorization, retroactive authorization, pre-certification for lack-of-prior-auth; formulary exception, tried and failed for off-formulary).
• Returns: per-phrase and per-category coverage with matched excerpts, plus ok: boolean.
• isError: true: when any phrase or any category is unaddressed — the calling workflow must revise the draft before moving on.

preferred_therapy_argument_generator

• Inputs: prior_therapies[] (name, class, dose, frequency, duration, outcome, discontinuation_reason), contraindications[] (type, detail, date), plan_preferred_agents[] (agents the payer names in the step-therapy/formulary policy).
• What it produces: one structured argument block per plan-preferred agent. Matches each agent against the prior-therapy list by normalized name or class, then falls back to matching against the contraindication list. For matched-tried agents, emits the trial outcome and discontinuation reason and two suggested sentences. For matched-contraindication agents, emits the contraindication detail and two suggested sentences. For unmatched agents, emits a placeholder sentence instructing the caller to supply evidence before the block can be rendered. Also returns unaddressed[] — agents with neither a prior trial nor a documented contraindication.
• isError: the generator does not error; it surfaces gaps via unaddressed[]. The downstream appeal_completeness_check and contradiction_checker are what block export when evidence is missing.

appeal_completeness_check

• Inputs: the normalized appeal record (see references/appeal-letter-structure.md).
• What it checks: header fields (provider name + NPI, provider phone or fax, payer name, appeals address or appeals fax, date of letter, appeal level); RE-line identifiers (member name + ID, denial date, payer reference number, claim-or-auth number); introduction phrasing (must mention both “appeal/reconsider/overturn” and “denial/adverse determination”); at least one rebuttal block per declared denial category; clinical summary; prior-therapy or contraindication data whenever the denial includes step-therapy, off-formulary, or not-medically-necessary; plan-preferred-therapy rebuttal with per-agent evidence for step-therapy and off-formulary; requested resolution; signature block with physician name + NPI; enclosure manifest including the LOMN for medical-necessity appeals (with a warning when the denial letter itself is not listed).
• Returns: { ok, missing[], warnings[] }.
• isError: true: when missing[] is non-empty.

contradiction_checker

• Inputs: the case_record from denial-intake-normalizer and the normalized appeal_record.
• What it checks: 10 rules across four dimensions. Branch mismatches (coding-edit or COB routed to clinical-appeal; NOMNC not routed to BFCC-QIO; timely-filing dressed up as clinical). CPT/ICD-10 anchor pairs (spine 22xxx CPTs against M43/M48/M50-54/M96/G54/G55.1 spine ICDs; joint injections 20610/20611 against M25.5/M17/M16/M19/M65/M67/M70/M75/M77; cardiac 33xxx/92xxx against I-family; oncology J9xxx against C-family + D37-48 + Z51.1/Z85). Therapy/rationale mismatch — the requested therapy name must appear in the rebuttal, clinical summary, or preferred-therapy rebuttal. Evidence gaps — step-therapy with no prior therapies and no contraindications; off-formulary without formulary-exception grounds; DRG/level-of-care without InterQual/MCG/Milliman/LSIP tokens; experimental/investigational without FDA label, compendia, or specialty-society tokens; out-of-network without in-network-search or No-Surprises-Act framing. RE-line hygiene — missing denial date or payer reference number.
• Returns: { contradictions[], ok } with severity: "error" | "warning" per entry.
• isError: true: when any error-severity contradiction is present.

Validation invariants

• Every denial category must have its own rebuttal block. Collapsing multi-category denials into a single generic medical-necessity argument is rejected by appeal_completeness_check.
• Step-therapy denials require prior-preferred-agent evidence OR contraindications. An empty step-therapy rebuttal is an automatic affirmation for the payer; contradiction_checker rule 4 blocks it.
• Medical-necessity appeals must enclose the LOMN. The enclosure manifest is checked for “letter of medical necessity” or “lomn”; missing LOMN blocks export.
• DRG / level-of-care denials must reference InterQual LSIP, MCG, or Milliman criteria. Generic medical-necessity language on a level-of-care denial trips contradiction_checker rule 6.
• RE line must carry the denial date and payer reference number. Appeal windows run from the denial date; the payer uses its own reference number to locate the case file. Rules 10a and 10b block export when either is missing.
• Contradictions block export. Any error-severity contradiction returns isError: true and the drafting workflow must resolve it before handing the draft to clinical-claim-evidence-mapper.

Getting started

1. Run denial-intake-normalizer first. The appeal letter builder reads case.json at the project root and refuses to draft when the case record is missing, when the branch is grievance-not-appeal, or when the branch is nomnc-expedited-determination (NOMNC cases follow the BFCC-QIO expedited pathway, not a full appeal letter).
2. Upload the chart excerpts that ground the clinical claims (chart notes, imaging, PT evaluations, medication lists) and the payer policy excerpt that names the plan-preferred agents or the coverage criteria cited in the denial.
3. Tell the skill to draft the appeal — “draft the appeal letter for the denial I just normalized” or “build the step-therapy rebuttal for this denial.”
4. Confirm denial_reason_rebuttal_checker matched every denial phrase and every denial category before the draft proceeds. Rewrite any unaddressed block.
5. Resolve every contradiction flagged by contradiction_checker. Errors block export; warnings do not, but should be reviewed.
6. Hand the draft to clinical-claim-evidence-mapper: run clinical_claim_extract_candidates, cite every real claim, and require clinical_claim_check_draft to return export_ready: true before rendering.
7. On success the skill writes the rendered letter to ./drafts/appeal-{case_id}.md, appends the claim-to-source index, and writes an audit-log entry. The letter is unsigned — the physician signs outside this workflow.