AGENT.md
An AGENT.md is a companion file that defines an agent's identity and behavioral guidelines when operating in a particular part of the graph. Where SKILL.md defines capabilities, AGENT.md defines personality and constraints — how the agent should communicate, what it should avoid, and what judgment calls to make.
Starting in 0.5.0, an AGENT.md alongside a composite compiles as a kind: document, navigable: false child at <parent-path>/AGENT. The plural form AGENTS.md (a Claude Code convention) is also recognized and compiles to <parent-path>/AGENTS — both forms are first-class.