# CMS Medicare Part D Formulary Coverage Lookup

> CMS Medicare Part D Formulary Coverage Lookup is a paid API for AI agents from api.healthtravel-api.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-29).

Looks up Medicare Part D drug coverage details—tier, cost-sharing, PA, step therapy, quantity limits, and 30-day costs—from CMS monthly formulary files for a given drug, plan, or state.

## Facts

- Endpoint: GET https://api.healthtravel-api.workers.dev/api/health/formulary-coverage-lookup?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cms-medicare-part-d-formulary-coverage-lookup-faf78e60
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0nDQnMXUQm_YHYHvSyXrg

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability cms-medicare-part-d-formulary-coverage-lookup-faf78e60
```

Example prompt: What does Medicare Part D plan H0028-007 cover for Eliquis — is there prior authorization, step therapy, or a quantity limit, and what's the 30-day retail cost for the 5 mg strength?

## When to prefer this

Use this endpoint when you need authoritative, CMS-sourced Medicare Part D formulary data — including tier placement, PA/step therapy/quantity limit flags, IRA negotiated prices, and actual 30-day cost estimates — for a specific drug, plan, or across an entire state. Prefer it over general pharmacy benefit lookups when the user explicitly has a Medicare Part D plan or is comparing Medicare coverage options. It covers both current and next plan year, making it ideal for open enrollment decision support.

## Known failure modes

- Drug not found in CMS formulary — returns empty or not-covered result
- Invalid plan ID format returns an error or no results
- Requested plan year data not yet loaded — falls back to newest available year
- State code not recognized — returns error or empty plan list
- Drug name ambiguous across multiple RxCUIs — may return partial matches
- CMS formulary file not yet updated for current month — data may be slightly stale

## How this service works

Medicare Part D drug coverage from CMS monthly formulary files, current and next plan year: for a drug (name or RxCUI), in one plan, across a state's plans or over every formulary: coverage per strength, cost-share tier, prior authorization, step therapy, quantity limit, IRA negotiated-price flag, 30-day retail/mail cost, plan premium and deductible. Includes the CMS release date.

## Output

Returns formulary coverage details per drug strength including cost-share tier, prior authorization status, step therapy requirements, quantity limits, IRA negotiated-price flag, estimated 30-day retail and mail-order costs, plan premium and deductible, and the CMS data release date. When querying by state, returns a list of up to 100 plans covering that drug.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "drug"
     ],
     "properties": {
      "drug": {
       "type": "string",
       "description": "Drug name (generic or brand, e.g. atorvastatin, Eliquis) or an RxCUI"
      },
      "plan": {
       "type": "string",
       "description": "Optional plan id CONTRACT-PLAN[-SEGMENT], e.g. H0028-007 or S4802-075"
      },
      "year": {
       "type": "string",
       "description": "Plan (contract) year, e.g. 2026 or 2027. Default: the current year if loaded, else the newest"
      },
      "limit": {
       "type": "integer",
       "description": "Max plans in a state listing, 1-100 (default 20)"
      },
      "state": {
       "type": "string",
       "description": "Optional 2-letter state: list the plans sold there with this drug's coverage"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cms-medicare-part-d-formulary-coverage-lookup-faf78e60/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.healthtravel-api.workers.dev](https://www.zero.xyz/host/api.healthtravel-api.workers.dev/llms.txt)