Email Thread Truncation

Last updated: January 17, 2026

Overview

When Pylon sends email replies that include thread history, extremely long email threads are automatically truncated to ensure reliable delivery. This prevents issues with email size limits while preserving the most relevant recent conversation context.

When Does Truncation Occur?

Email threads are truncated when the total character count of all messages in the thread exceeds 1,000,000 characters. This limit ensures compatibility with email service providers while keeping the most important parts of your conversation intact.

Note: formatting contributes to whether a message exceeds the character limit.

How It Works

Truncation Behavior

When an email thread exceeds the character limit:

  1. Messages are prioritized by recency - Newer messages are kept, older messages are removed

  2. Truncation occurs at message boundaries - Complete messages are included or excluded; messages are never partially cut off

  3. Most recent context is preserved - The latest exchanges in the conversation remain intact