Quick Start

1. POST a clinical letter

Send a Markdown letter to /api/v1/agent/query. The body is the entire request — no headers required beyond Content-Type.

curl -X POST https://api.appendix.com/api/v1/agent/query \
  -H "Content-Type: application/json" \
  -d '{
    "query": "# Chief Complaint\nCough x 2 weeks\n\n# Age and Sex\n35-year-old male\n\n# History of Present Illness\nProductive cough with yellow-green sputum for 2 weeks. Worse in the morning.\n\n# Review of Systems\nNo fever, no weight loss, no night sweats.\n\n# Past Medical History\nNo chronic conditions.\n\n# Allergies\nNKDA\n\n# Family History\nFather with asthma.\n\n# Social History\nNon-smoker, office worker.\n\n# Diagnosis\nAcute bronchitis.\n\n# Treatment Plan\nBenzonatate for cough suppression."
  }'

2. Read the response

The API evaluates the letter against 11 required criteria. final_decision_ready is true when the letter is complete:

{
  "session_token": "abc123-def456",
  "encounter_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "encounter_token": "7f3e...<64-char hex>",
  "encounter_expires_at": "2026-02-29T12:00:00Z",
  "evaluation": { /* 11 booleans */ },
  "final_decision_ready": true,
  "missing_items": [],
  "completed_items": [ /* 11 labels */ ],
  "checkout_url": "https://appendix.com/checkout/a1b2c3d4-...?token=xyz",
  "next_steps": "Medical information is complete. Please direct the user to the checkout URL to provide demographics, ID verification, and payment."
}

If the letter is missing required fields, final_decision_ready is false and missing_items tells you what to ask the user about. Add the missing info and POST again with the same session_token.

3. Hand the user the checkout URL

Show the user the checkout_url. They sign in, verify identity, pay, and submit. A board-certified physician personally reviews the submission and writes back with an assessment, guidance, and a prescription if appropriate.

4. Poll for the physician’s reply

Save the encounter_id and encounter_token from step 2. Use them on the agent chat endpoints to read the physician’s message and reply on the user’s behalf. The token is valid for 7 days.

Going further

• For paying subscribers, authenticate with an API key and bind the encounter to a specific person on the account; the API can then advance straight to submitted without a checkout round-trip.
• See Letter Format for the 11 sections the evaluator checks.
• See the Conditions List for what we treat.