SOUL.md

SOUL.md is a new convention for defining AI agent personality in a single markdown file. It solves the problem of inconsistent, scattered agent behavior by providing a structured, human-readable format that encapsulates identity, tone, rules, and constraints. The concept is rapidly gaining adoption in the AI agent community as a lightweight alternative to complex configuration systems. By placing a SOUL.md file at the root of an agent project, developers can specify how the agent should think, respond, and interact, making agent behavior predictable and portable. This approach draws inspiration from README.md conventions and applies them to agent design. Early adopters report that SOUL.md simplifies collaboration and version control for agent personalities. While the format is still emerging, it has already sparked discussions about standardization and best practices. The term reflects a shift toward treating agent personality as a first-class artifact in development workflows.

Explosive adoption on X (Twitter) as developers share their SOUL.md files and discuss best practices for agent personality design.