Core Concepts

preprocess()

Accepts a raw RFC 5322 email string and returns a structured ParsedEmail object. Handles MIME multipart messages, HTML and plain-text body variants, and normalises all character encodings including zero-width characters and HTML entities.

function preprocess(
  raw: string
): Promise<ParsedEmail>

What it does internally:

Parses the MIME structure and selects the most relevant body variant (HTML preferred over plain text)
Converts HTML to Markdown, preserving semantic structure
Detects and removes quoted reply chains across Gmail, Outlook, Apple Mail, and non-standard clients
Detects and removes email signatures
Normalises zero-width characters and HTML entities
Strips URLs while preserving anchor text

ParsedEmail type

Field	Type	Description
subject	string \| null	Decoded subject line
sender	Address	From field, parsed into name and email
recipients	Address[]	To, Cc recipients
date	string \| null	ISO 8601 date string
body	string	Cleaned Markdown body
ctas	CTA[]	Extracted calls-to-action
rfc_message_id	string \| null	RFC 5322 Message-ID header

toLLMContext()

Accepts a ParsedEmail and returns a Markdown string formatted for direct inclusion in a prompt. The output includes a structured header block followed by the cleaned body.

function toLLMContext(
  parsed: ParsedEmail,
  options?: LLMContextOptions
): string

LLMContextOptions

Option	Type	Default	Description
format	”markdown” \| “plain"	"markdown”	Output format
includeHeaders	boolean	true	Prepend From / Subject / Date header block
includeCTAs	boolean	true	Append extracted CTAs at the end