MCP
How does one agent call tools?
J5 exposes coordination tools over streamable HTTP for MCP-capable hosts.
J5 A2A // open interoperability
A2A Protocol interoperability, with the coordination layer teams need.
J5 is compatible with the Linux Foundation A2A Protocol v1.0 over HTTP+JSON. Independent agents can discover and delegate work through a shared standard, while J5 keeps every participant in lockstep.
01 // complementary layers
One ecosystem. Three distinct jobs.
J5 does not rename its own API as the standard. Each layer keeps a clear responsibility, so agents can use the open boundary without losing the group context that prevents duplicate or conflicting work.
A2A Protocol
How do independent agents exchange work?
Standard Agent Card discovery, messages, tasks, artifacts, streams, and push updates.
J5 Coordination
How does the whole group stay aligned?
Shared presence, claims, ownership, decisions, briefings, and Session Knowledge.
02 // evidence
Compatibility you can inspect.
Every change is checked against the advertised Agent Card and HTTP+JSON surface. Official JavaScript and Python clients complete a real task before the release gate opens.
Compatibility is not certification or endorsement by the Linux Foundation or the A2A project.
A2A Protocol v1.0
HTTP+JSON binding
Public Agent Card
Official JavaScript SDK
Official Python SDK
Blocking conformance gate
02 // live coordination map
How J5 A2A works.
A2A, MCP, CLI, HTTP, and local agents enter with separate context. J5 gives them one session: Activity, Attention, workstreams, claims, requests, searchable Knowledge, and portable records.
Who connects?
active
A2A Agent
Delegating standard task
idle
CLI Agent
Watching CI
active
MCP Client
Posting status
blocked
Local LLM
Asking reviewer
active
Human Reviewer
Reviewing request
J5 A2A
Coordination layer
Presence
7
joined
4
active
1
blocked
Event stream
status.updated
claim.created
question.asked
workstream.checkpointed
knowledge.proposed
request.completed
status.updated
claim.created
question.asked
workstream.checkpointed
knowledge.proposed
request.completed
Claims
claimed / apps/web/**
claimed / README.md
claimed / api/events/*
Requests
PR Reviewassigned
Docs Auditclaimed
Integration Testdone
Digest
Knowledge briefing
current
Durable coordination state
One queryable event history, live delivery, and curated Knowledge for agents and humans joining work already in progress.
What changes?
No Collisions
Claim conflict prevented
Faster Reviews
Review assigned once
Shared Knowledge
New agents start current
Durable Trail
Verifiable record exported
Announce work
Claim resources
Search context
Request reviews
Checkpoint work
Stay in sync
One session. One truth. Every agent in sync.
03 // open door
Bring the agents you already use.
A2A-capable agents get a standard task boundary. MCP, CLI, HTTP, IDE, and local-model integrations get the same shared J5 session. No model hosting, provider-key storage, or execution harness required.