The protocol

Open protocol.
Any agent.

A thin JSON-RPC 2.0 layer on top of MCP. Thirteen methods, six concept groups. Any runtime that can spawn a subprocess and send a JSON line plugs in. Claude Code is the reference client. Python is proven. Cursor, Aider, LangChain, or your own agent loop come for free.

Read the spec →Python reference client →Cross-runtime benchmark →
Handshake

Server advertises protocol version and which optional features it supports.

list_capabilities
Records

Write typed, validated ActionRecords. Fetch any record by id — unknown ids return a structured not_found fault, never fabricated content.

record_actionfetch_action
Query

Filter by type, session, cwd, agent, parent_id, or timestamp. Cheap counts for dashboards, FTS5 full-text search across content, full ActionRecords for the agent.

query_actionscount_actionssearch_actions
Causality

Walk the DecisionGraph. Given an action id, return its chain back to the root — the why behind any edit or decision.

trace_causality
Working set

Open or hydrate a session. Atomic swap to add/remove pointers. Page-fault when a pointer isn't resident. Pre-compact keeps pinned + MRU in budget so compaction becomes a page-swap, not a summary.

open_sessionget_manifestswap_sessionfetch_pagebefore_compact
Atlas

NDJSON export/import of the substrate. Move an agent's accumulated knowledge between machines, teams, or models — topologically ordered.

export_snapshotimport_snapshot

Works with

Your stack. Any agent.
One substrate.

Two labels only. Shipped = we use it every day. Compatible = any agent speaking MCP / GMP can connect. No testimonials, no pretend logos.

Claude CodeshippedPlugin ships today
GMP protocolshippedv0.2 spec + reference server
Python agentsshippedReference client in-repo
MCP ecosystemcompatibleAny MCP client can connect
CursorcompatibleMCP-compatible agent
AidercompatibleMCP-compatible agent
LangChain / LangGraphcompatibleVia MCP integration
LlamaIndexcompatibleVia MCP integration