Module message 

Message types for the A2A protocol.

A Message is the fundamental communication unit between a client and an agent. Each message has a MessageRole ("ROLE_USER" or "ROLE_AGENT") and carries one or more Part values.

Part structure (v1.0)

Part uses JSON member name as discriminator per v1.0 spec:

• {"text": "hello"}
• {"raw": "base64...", "filename": "f.png", "mediaType": "image/png"}
• {"url": "https://...", "filename": "f.png", "mediaType": "image/png"}
• {"data": {...}}

Structs

FileContent

Content of a file part.

Message

A message exchanged between a client and an agent.

MessageId

Opaque unique identifier for a Message.

Part

A content part within a Message or crate::artifact::Artifact.

Enums

MessageRole

The originator of a Message.

PartContent

The content of a Part, discriminated by JSON member name per v1.0 spec.