Agent protocols · MCP · A2A · the diagrams

Section 01 · Agentic AI Foundation - one foundation, many specs

All the protocols under one roof.

Agentic AI Foundation (Linux Foundation) · ~170 members

The 2025-26 protocol wars ended in consolidation. Pick MCP + A2A. Compose, don't choose.

Section 02 · MCP · the tool/context protocol

MCP - agents discover tools.

Model Context Protocol · stateless HTTP core (RC 2026-07-28)

#88241's agent reaches for a tool - request out, context back. ~14,000 servers tracked; the Oct 2026 RC drops session state, so you load-balance anywhere.

Section 03 · MCP 2026 · the production roadmap

Tasks + Server Cards.

David Soria Parra · MCP lead maintainer · 2026 roadmap

Two new primitives. Tasks turn MCP into submit-now-fetch-later. Server Cards make discovery sessionless.

Section 04 · the production seam

Gateway + sheath.

Bloomberg · Kong · Arcade · vollko / shack-gateway · enterprise wraps around vanilla MCP

Gateway: the seam. Sheath: the wrap. Every call #88241 makes passes five rings before it touches data.

PROGRESSIVE DISCOVERY · 4 meta-tools

shack-gateway (vollko OSS)

instead of dumping every downstream tool schema into the client (~5 k tok each), the gateway exposes four meta-tools:

· shack_list_tools - compact {name, server, summary}
· shack_describe_tool - full schema on demand
· shack_call_tool - routed via security pipeline
· shack_list_servers - tool counts per server

scales past 50 servers without busting the context budget

SECURITY PIPELINE · per call

declarative · auditable

every call passes through the same four gates before it leaves the gateway:

· workspace sandbox - path containment
· allow / deny rules - bash(rm -rf:*)
· pre / post hooks - modify or reject
· log redaction - tokens / keys / secrets

JSON-RPC 2.0 over stdio · rs / ts / py · Apache-2.0

Section 05 · MCP-UI · UI as tool output

Three render modes.

Ido Salomon + Liad Yosef · MCP-UI · ui:// scheme · intent postMessage loop

MODE 1

Inline HTML

lightweight widget · same trust domain as host

MODE 2

External URL

full web app · sandboxed iframe · vendor app

MODE 3

Remote DOM

host renders native components · brand-consistent

Agent emits UI · host sandboxes it · user clicks fire typed intents back. Tool output becomes interactive.

Section 05b · MCP provenance

Trust the tools your agent reaches for.

vollko / mcp-provenance · May 2026: OX Security disclosed tool poisoning across 150M+ MCP downloads

npm provenance attests the build. Sigstore attests the artifact. Nobody attested the capability - until this.

Section 06 · A2A · agent-to-agent task delegation

A2A - agents hire agents.

v1.0 · Linux Foundation · 150+ orgs (Mar 2026)

#88241 needs finance data - the coordinator delegates to an agent in another org. Each agent publishes a card; the spec is the contract, no SDK lock-in.

Section 07 · the envelope on the wire

CloudEvents wraps everything.

every event answers five questions · that's it

However it travels, #88241 rides inside the same envelope - sealed, then on the wire. Fields stay constant; the payload carries the protocol-specific message.

Section 08 · discovery