Overview

OpenCheckpoint is a document format. It defines no transport, RPC, or storage, so it can travel inside whatever channel already connects the systems involved, and it points back into the session records those systems keep.

Two mechanisms connect it to other standards:

• Carrying a checkpoint. A protocol transports the document, using the proposed media type application/vnd.opencheckpoint+json.
• Referencing history. source.session_refs points to sessions, tasks, or events in another protocol’s records. A consumer that can read those records may use them; one that cannot still understands the checkpoint.

The guides below are informative and describe patterns for each. A normative binding, such as an extension identifier in another protocol, belongs to that protocol’s own process.

Guide	Covers
MCP	Exposing checkpoints as resources; referencing MCP resources.
A2A	Returning checkpoints as artifacts; referencing contexts and tasks.
ACP	Passing checkpoints to coding agents; mapping plans and tool calls.
Session logs and runtimes	Agent Session Protocol, pi, LangGraph, OpenAI Agents SDK, Open Responses.