A2A Releases Official CLI Tool

The A2A project has released an official command-line interface (CLI) tool for the A2A protocol. This tool was developed to address inconsistencies in existing language-specific SDKs and community CLIs, and is currently at the v0.2.0 release stage.

Key Features and Usage

• Agent Invocation: Use the send command to transmit messages either synchronously or in real-time streaming via the --stream option. Using --async allows for asynchronous execution, with status tracking available via task get --wait.
• Server Mode: The server command allows running A2A servers in three modes: Echo (message reflection), Proxy (request forwarding and logging), and Exec (standard I/O-based agentization).
• Output and Authentication: Supports output in text, JSON, and JSONL formats, with credentials managed via .env files or environment variables.

Caveats and Limitations

• Exit Codes: The CLI's exit codes indicate only the technical success of the operation. Business logic failures in tasks (such as FAILED, REJECTED, etc.) may return exit code 0, so you must check the output status directly.
• Not Suitable for Production: The project is currently in the alpha stage and the specification is not yet ratified. It is recommended for development, debugging, and automated testing rather than production environments.
• License: Licensed under Apache License 2.0, allowing for both personal and commercial use.