a2a-protocol skillA
a2a-protocol is agent-read markdown (skill) from akillness/jeo-skills: Agent-to-Agent horizontal messaging — Linux Foundation AAIF 2026 standard. Use when multiple agents across systems/vendors need to exchange tasks, results, or capabilities without sharing a runtime..
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
# A2A Protocol
## Overview
MCP exposes *tools* to an agent. A2A connects *agents* to *agents*. The 2026 Linux Foundation AAIF specification standardizes capability cards, task envelopes, and the negotiation handshake — so a Claude agent can hand work to a Codex agent (or a third-party vendor agent) without bespoke glue.
## When to use
- Two agents need to collaborate across runtime/vendor boundaries
- You're tired of writing custom HTTP wrappers between agent systems
- Cross-org agent collaboration (your billing agent ↔ vendor support agent)
- Mesh / federated agent systems
## Don't use when
- Both agents share a runtime (just call a function or use orchestrator)
- One-direction tool call → use MCP (`mcp-builder`)
## Core concepts
| Concept | What |
|---------|------|
| **Agent Card** | Public manifest — capabilities, endpoint, auth, SLAs |
| **Task Envelope** | Job description + inputs + budget + deadline |
| **Artifact** | Typed output a task produces |
| **Stream** | Long-running task progress channel (SSE) |
| **Negotiation** | Optional capability/SLA agreement before send |
## Agent Card example
```json
{
"name": "acme-research-agent",
"version": "0.4.1",
…Read the whole file at its exact version.
How to install
mdr add akillness/jeo-skills/a2a-protocol@git:20260920.2a2b733mdr add akillness/jeo-skills/a2a-protocol@sha256:afc69c4bc714498fPin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_h5vkonft2muqlkl7)
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Versions
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260920.2a2b733 latest | 2026-09-20 | 2a2b733 | 3,869 B | A | view · diff |
| git:20260919.9f2a908 | 2026-09-19 | 9f2a908 | 3,875 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (3869 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
akillness/jeo-skills · 47 stars · license none · pushed 2026-09-22 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_h5vkonft2muqlkl7 GET https://markdownregistry.com/api/v1/resolve?ref=akillness/jeo-skills/a2a-protocol GET https://markdownregistry.com/api/v1/blob/afc69c4bc714498facb8fba69fdf5802869981f12f2f49438d23924f4b0b057f
Your agent does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.