Concordia Protocol

Open negotiation standard for AI agents — structured proposals, binding commitments, and verifiable session receipts

When your agent needs to negotiate or make a deal, Concordia gives it a structured way to propose, counter, commit, and build a track record.

python3 -m venv /tmp/concordia-verify-py /tmp/concordia-verify-py/bin/pip install rfc8785 pynacl jsonschema /tmp/concordia-verify-py/bin/python conformance/reference-runner/runner.py conformance/vectors | tail -1

(cd conformance/reference-runner-js && npm ci) node conformance/reference-runner-js/runner.mjs conformance/vectors | tail -1

Expected summary for both:[SUMMARY] positive=48 mutation=1484 canary=5 ok=1537 fail=0

Contract:conformance/RUNNER_CONTRACT.md. Profiles:conformance/PROFILES.md. Registry:conformance/IMPLEMENTATIONS.md.

Agent A: I want to buy a camera Agent B: I have one, $2000 Agent A: Too expensive, $1800? Agent B: $1950 final Agent A: ...ok? Agent B: ...ok? → No signed agreement. No clear terms. No reputation signal.

Agent A proposes: Camera, $2000 Agent B counters: $1900, shipping Agent A counters: $2000 for pickup, $2050 shipped Agent B accepts: $2050 shipped → Signed agreement. Clear terms. Reputation attestation issued.

{ "concordia": "0.1.0", "type": "negotiate.open", "body": { "terms": { "item": { "value": "Canon EOS R5, 15K shutter count" }, "price": { "value": 2200, "currency": "USD" }, "condition": { "value": "like_new" }, "delivery": { "value": "local_pickup" } } }, "reasoning": "Listing based on recent eBay sold comps." }

{ "type": "negotiate.counter", "body": { "terms": { "price": { "value": 1900, "currency": "USD" }, "delivery": { "value": "shipping" } } }, "reasoning": "I prefer shipping and want a better price." }

{ "type": "negotiate.counter", "body": { "conditions": [ { "if": { "delivery": "local_pickup" }, "then": { "price": { "value": 2000 } } }, { "if": { "delivery": "shipping" }, "then": { "price": { "value": 2050 } } } ] }, "reasoning": "Pickup is cheaper for me, shipping costs extra." }

{ "type": "negotiate.accept", "body": { "accepted_terms": { "item": "Canon EOS R5", "price": { "value": 2050, "currency": "USD" }, "delivery": "shipping" } } }

Both agents sign. The agreement passes to a payment protocol (ACP, Stripe, etc.) for settlement. A reputation attestation is automatically issued.

pipx install "concordia-protocol[server]"

python3 -m venv .venv .venv/bin/pip install "concordia-protocol[server]"

Note:Concordia requires Python 3.10+. macOS ships Python 3.9 with Xcode, so install a newer version first:

Library-only consumers can installconcordia-protocolwithout the MCP server dependencies. Theconcordia-mcp-servercommand requires theserverextra and prints an install hint when that extra is missing.

git clone https://github.com/eriknewton/concordia-protocol.git cd concordia-protocol pip install -e ".[dev]"

claude mcp add concordia -- concordia-mcp-server

openclaw mcp set concordia '{"command":"concordia-mcp-server"}'

openclaw mcp set concordia '{"command":"/path/to/.venv/bin/python3","args":["-m","concordia"]}'

from concordia import Agent, BasicOffer, generate_attestation # Create two agents (Ed25519 keys auto-generated) seller = Agent("seller") buyer = Agent("buyer") # Seller opens a negotiation session = seller.open_session( counterparty=buyer.identity, terms={"price": {"value": 100.00, "currency": "USD"}}, ) buyer.join_session(session) buyer.accept_session() # Buyer accepts the session (PROPOSED -> ACTIVE) # Buyer counters at $80 buyer.send_counter(BasicOffer(terms={"price": {"value": 80.00, "currency": "USD"}})) # Seller accepts seller.accept_offer() print(session.state.value) # "agreed" # Generate a signed reputation attestation att = generate_attestation(session, {"seller": seller.key_pair, "buyer": buyer.key_pair}) print(att["outcome"]["status"]) # "agreed"

When you share a signed object, include verification material with it:

from concordia import KeyPair, public_key_from_b64url, sign_message, verify_signature producer = KeyPair.generate() record = {"type": "example.receipt", "body": {"status": "agreed"}} signature = sign_message(record, producer) material = producer.verification_material() verifier_key = public_key_from_b64url(material["public_key_b64url"]) assert verify_signature(record, signature, verifier_key) tampered = {record, "body": {"status": "rejected"}} assert not verify_signature(tampered, signature, verifier_key)

Settlement ACP · AP2 · x402 · Stripe · Lightning ──────────────────────────────────────────────────────── Agreement ★ CONCORDIA PROTOCOL ★ ──────────────────────────────────────────────────────── Trust Reputation Attestations ──────────────────────────────────────────────────────── Communication A2A · HTTPS · JSON-RPC ──────────────────────────────────────────────────────── Discovery Agent Cards · Well-Known URIs ──────────────────────────────────────────────────────── Tools MCP · Function Calling · APIs ──────────────────────────────────────────────────────── Identity DIDs · KERI · OAuth 2.0

When your agent needs security, privacy, and control,Sanctuary Frameworkadds encrypted state, approval gates, and automatic sensitive-data filtering.

- Sanctuaryhandles security, privacy, and control
- Concordia**handles structured deals and reputation

npx @sanctuary-framework/mcp-server pip install concordia-protocol

They work independently, but together they're more powerful.

…