> Documentation index: https://rift.sh/llms.txt

# Rift vs A2A

A2A is how agents from different vendors hand each other tasks. Rift is how they share files.

### What A2A is

Agent2Agent is an open protocol for agents built by different vendors. An agent publishes a card that describes it, and other agents send it tasks, follow their progress and receive the results. It runs over ordinary HTTPS, so it fits behind an existing API gateway. Version 1.0 was released in March 2026.

### How they differ

A2A defines the conversation between two agents and leaves authorization to each side. A file travels as a copy inside a message, or as a link to someone's storage. Rift keeps one set of files in sync and defines who can read them.

- Identity
  - A2A: A credential for whatever scheme the other agent's card declares.
  - Rift: A key that each machine and agent makes for itself. No account.

- Smallest share
  - A2A: Not defined. The specification leaves authorization to each implementation.
  - Rift: A folder, a subfolder or one file, as read or write.

- Who checks access
  - A2A: Each receiving server, by its own policy.
  - Rift: Each machine that receives a file checks the grant itself.

- Who can read your files
  - A2A: Both ends, and anything between them that terminates TLS. We found no end-to-end encryption in the specification.
  - Rift: Only the machines you shared with. Rift Cloud holds ciphertext.

- When your machines are off
  - A2A: Nothing moves unless the other agent's server is up.
  - Rift: Files stored in Rift Cloud stay available.

### Which to choose

Choose A2A when

- Agents from different vendors need to delegate tasks to each other.
- You want a standard task model over HTTPS.
- Results are small enough to send in a message.

Choose Rift when

- Two agents need to keep working on the same files.
- The files are large or change often.
- No gateway or proxy between the two agents should be able to read the files.

### Using them together

One agent can hand another a task over A2A while both keep their files in Rift.

[Use Rift with A2A](https://rift.sh/docs/use-with/a2a.md)

Based on the A2A specification, version 1.0.1, read in October 2026. Sources: [specification](https://github.com/a2aproject/A2A/blob/v1.0.1/docs/specification.md) , [releases](https://github.com/a2aproject/A2A/releases).