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Skytale

coffeeAGNTCY on Skytale

coffeeAGNTCY is AGNTCY’s multi-agent reference application. A Coffee Exchange agent negotiates prices with a Coffee Farm agent using the SLIM transport layer. This tutorial shows two ways to add Skytale’s MLS encryption to the flow.

Prerequisites

Section titled “Prerequisites”
  • A Skytale account (skytale signup you@example.com)
  • Python 3.10+
  • pip install skytale-sdk

Part 1: Drop-in with existing coffeeAGNTCY

Section titled “Part 1: Drop-in with existing coffeeAGNTCY”

If you already have coffeeAGNTCY running, point its transport at the Skytale relay. The relay exposes a gRPC interface on port 5000 that accepts SLIM-formatted messages.

1. Clone coffeeAGNTCY

Section titled “1. Clone coffeeAGNTCY”
Terminal window
git clone https://github.com/agntcy/coffeeAGNTCY.git
cd coffeeAGNTCY

2. Set the transport endpoint

Section titled “2. Set the transport endpoint”

In your coffeeAGNTCY environment config, set the relay as the transport server:

Terminal window
export TRANSPORT_SERVER_ENDPOINT="relay.skytale.sh:5000"
export SKYTALE_API_KEY="sk_live_..."

3. Run the agents

Section titled “3. Run the agents”

Follow the standard coffeeAGNTCY instructions. Messages between the Exchange and Farm agents now route through the Skytale relay with MLS encryption.

Part 2: Native SDK approach

Section titled “Part 2: Native SDK approach”

Build the same Exchange/Farm negotiation directly with the Skytale Python SDK. This approach gives you full control over channels, invite tokens, and protocol envelopes.

Installation

Section titled “Installation”
Terminal window
pip install skytale-sdk

The example script

Section titled “The example script”

The full script is at sdk/examples/coffeeagntcy_skytale.py. Here’s a walkthrough of the key pieces.

Channel setup

Section titled “Channel setup”

The Exchange agent creates a channel and generates an invite token. The Farm agent joins with that token — no manual key package exchange needed.

from skytale_sdk import SkytaleChannelManager


# Exchange creates the channel
exchange = SkytaleChannelManager(identity="exchange", api_key="sk_live_...")
exchange.create("coffeeagntcy/trading/negotiation")
token = exchange.invite("coffeeagntcy/trading/negotiation")


# Farm joins with the invite token
farm = SkytaleChannelManager(identity="farm", api_key="sk_live_...")
farm.join_with_token("coffeeagntcy/trading/negotiation", token)

A2A protocol envelopes

Section titled “A2A protocol envelopes”

Messages use Envelope with Protocol.A2A so they’re tagged for A2A tooling while being MLS-encrypted end-to-end.

import json
from skytale_sdk import Envelope, Protocol


def make_a2a_message(sender: str, text: str) -> Envelope:
    """Wrap a text message in an A2A protocol envelope."""
    payload = json.dumps({
        "parts": [{"type": "text", "text": text}],
        "sender": sender,
    }).encode("utf-8")
    return Envelope(
        protocol=Protocol.A2A,
        content_type="application/json",
        payload=payload,
    )


# Exchange sends a quote request
exchange.send_envelope(
    "coffeeagntcy/trading/negotiation",
    make_a2a_message("exchange", "Requesting quote: 100 bags Arabica, delivery Q3 2026"),
)


# Farm receives and responds
envelopes = farm.receive_envelopes("coffeeagntcy/trading/negotiation", timeout=10.0)
for env in envelopes:
    body = json.loads(env.payload)
    print(body["parts"][0]["text"])

Local dev mode

Section titled “Local dev mode”

Use --mock to run without a relay or API key. The SDK uses in-memory transport for local testing.

Terminal window
python coffeeagntcy_skytale.py --mock
=== coffeeAGNTCY on Skytale ===
Mode: mock (local)


[Exchange] Created channel: coffeeagntcy/trading/negotiation
[Exchange] Invite token generated
[Exchange] Sent quote request
[Farm] Joined channel: coffeeagntcy/trading/negotiation
[Farm] Received: Requesting quote: 100 bags Arabica, delivery Q3 2026
[Farm] Sent quote
[Exchange] Received: Quote: $4.20/lb Arabica, 100 bags, FOB Santos. Valid 24h.
[Exchange] Deal confirmed
[Farm] Received: Accepted. Locking price at $4.20/lb for 100 bags.


=== Negotiation complete ===

Running against the hosted relay

Section titled “Running against the hosted relay”
Terminal window
skytale signup you@example.com
python coffeeagntcy_skytale.py

Or pass credentials explicitly:

Terminal window
python coffeeagntcy_skytale.py --api-key sk_live_... --endpoint https://relay.skytale.sh:5000

Environment variables

Section titled “Environment variables”
VariableDefaultDescription
SKYTALE_API_KEY~/.skytale/api-keyAPI key for authenticated access
SKYTALE_RELAYhttps://relay.skytale.sh:5000Relay server URL
SKYTALE_API_URLhttps://api.skytale.shAPI server URL
SKYTALE_MOCK—Set to 1 or true for local dev mode

Next steps

Section titled “Next steps”