A2CN v0.2.0 — Session Invitation, Platform Adapters, Impasse Detection

A2CN v0.2.0 Release Notes

Released: April 2026
Spec: v0.2.0 (3,300+ lines)
Tests: 202 passing
License: Apache 2.0

What's new in v0.2.0

Session Invitation (Component 8)

Solves the cold-start problem. A buyer agent can now invite a supplier who has no A2CN endpoint yet via a signed SessionInvitation delivered through existing webhook infrastructure (Fairmarkit BID_CREATED, email, or Meeting Place). The invitation is ES256-signed using the inviter's DID key. The supplier verifies authenticity before activating any endpoint.

Platform adapters

• Fairmarkit — FairmakitEventParser translates BID_CREATED webhook payloads into A2CN goods_procurement terms and translates agreed terms back into Fairmarkit's response API format. Path B integration — zero Fairmarkit platform changes required.
• Salesforce Revenue Cloud — RevenueCloudAdapter translates Revenue Cloud Pricing API responses into A2CN offer terms and translates agreed terms into Revenue Cloud order payloads.
• Keelvar — SOURCING_EVENTS_FEED_UPDATED webhook → A2CN session translation.

Deal-type-specific terms schemas

• goods_procurement — delivery_days, unit_of_measure, manufacturer and internal part numbers
• saas_renewal — seat_count, subscription_tier, support_tier, auto_renew_terms, uptime_sla_percent

Impasse detection

Configurable impasse_threshold in session_params. When N consecutive rounds show less than 0.5% movement in total_value, session transitions to IMPASSE. Default N=3, configurable 1-10.

LLM negotiation skills file

Reference skills file for LLM agents participating in A2CN sessions. Covers warmth-dominance calibration, chain-of-thought reasoning patterns, and Inject+Voss prompt injection defense. Based on Vaccaro et al. (2026) arXiv:2503.06416v3 — 182,812 AI-to-AI negotiations.

Webhooks at Level 2

Terminal state webhooks (COMPLETED, REJECTED_FINAL, WITHDRAWN, IMPASSE, TIMED_OUT) promoted from RECOMMENDED to REQUIRED for Level 2 conformance. Async delivery with exponential backoff retry.

Installation

git clone https://github.com/A2CN-protocol/A2CN.git
cd A2CN/reference-implementation/python
pip install -e .

Run the demos

# SaaS renewal bilateral negotiation
python examples/saas_renewal.py

# Session Invitation / Fairmarkit integration pattern
uvicorn server:app --port 8002  # Terminal 1
python examples/invitation_flow.py  # Terminal 2

# Keelvar sourcing event end-to-end
python examples/keelvar_demo.py

Run the tests

pip install -r requirements.txt
pytest tests/ -v
# 202 passed

What's next (v0.3)

• Meeting Place — neutral transaction hosting, mandate management, EU AI Act compliance export
• Ed25519 as alternate signing suite (coordinated with Concordia Protocol)
• Delegation chain support in mandate verification
• Joint A2A extension proposal with Concordia Protocol
• TypeScript reference implementation
• pip install packaging