Definition
Plain language
A plain-text file in a software project that explains what the project is and how to use it.
As stated in the literature
A documentation file (usually markdown) at the root of a code repository describing setup and usage; because coding agents read it at runtime, a poisoned README is a vector for indirect prompt injection and for guardrail denial-of-service attacks.
Why it matters: It is the first thing people and agents read to understand a project, but because it's trusted, a tampered README can also be used to mislead an agent.
For example, opening a project's README usually tells you in plain terms what the software does and how to install and run it.
Heard on the show
“An attacker can put “delete the database” into a README file.”Episode 250 — The Same Model Refused a Backdoor, Then Its Own Sub-Agent Ran It