Service Interaction Explorer

Follow every message that moves between the agent, gateways, wallets, and external services. Pick a scenario, step through the sequence, and correlate the run with metrics, traces, and logs.

Human actorUI surfaceService / APIIssuer / trustObservabilityInfrastructure

Agent executes a high-value MCP purchase that requires presence. The flow covers discovery, gateway policy enforcement, wallet approval, and the TAP-signed handoff to the merchant.

The agent first behaves like a customer concierge: it queries the MCP tool catalog, verifies pricing, and determines whether the cart pushes the policy past its purchase threshold. Because the MacBook Air exceeds the $1000 rule, the agent must step up by creating a presentation request with AgentGateway and waiting for the human to complete the wallet ceremony.

Once the wallet supplies Agent Identity and Proof-of-Presence credentials, AgentGateway evaluates issuer trust, enforces anti-replay, and mints a Decision JWT scoped to the vendor. The agent then packages that JWT as TAP evidence, signs the downstream `retail.place_order` call, and the merchant verifies both the TAP envelope and the decision before fulfilling the order.

Step Trace

1
Customer asks for the purchase
Chat / HTTPS
The human requests “Buy the latest MacBook Air for me.” and the agent logs the intent.
Mode: MCPTriggers retail search
2
Agent queries vendor catalog
HTTP MCP Tool
Agent UI calls vendor MCP tool `retail.search_latest` to fetch current pricing and SKU metadata.
Returns SKU MBA13-2025Price: 1200 USD
3
Presence policy enforced
POST /presentations/requests
Because the quote exceeds the $1000 threshold, the agent requests a presentation from AgentGateway.
Policy: purchase_threshold_usdRequires presence
4
Gateway checks issuers & trust
HTTP /trust-status, /.well-known/jwks.json
AgentGateway pulls trust status and issuer keys to verify the upcoming wallet presentation.
Validates Agent Identity issuerEnsures PoP issuer trusted
5
Wallet approval requested
QR / deeplink
The agent surfaces the QR/deeplink and the human opens it in the wallet.
UI shows QR codePrompt states presence required
6
Wallet sends credentials
POST /presentations/submit
Wallet mock posts Agent Identity + PoP VCs back to AgentGateway to satisfy the request.
Anti-replay enforcedPoP assurance captured
7
Decision JWT issued
GET /presentations/{id}/result
AgentGateway verifies the claims, mints a Decision JWT bound to the vendor audience, and Agent UI polls for readiness.
Token TTL ≈ 60saud=https://vendor.svipe.id
8
TAP-signed order request
POST /retail/place_order + X-TAP-* headers
Agent UI signs a Trusted Agent Protocol envelope (Decision JWT evidence) and posts the order.
Visa TAP HTTP signatureEvidence: Decision JWT inside TAP payload
9
Vendor verifies TAP + decision
Verify TAP → GET /.well-known/jwks.json • POST /introspect
Vendor validates the TAP signature, nonce, timestamp, then verifies the Decision JWT with AgentGateway.
Anti-replay via nonce cacheJWT checked against AgentGateway JWKS
10
Order confirmation
HTTP JSON Response
Vendor responds with order_id + pickup_code, which the Agent UI relays to the human.
UI shows ✅ Order placedPickup code displayed

Customer asks for the purchase

The human requests “Buy the latest MacBook Air for me.” and the agent logs the intent.

From: user

To: agent-ui

Payload / call

Buy the latest MacBook Air for me.

Documentation:

SCRIPT.md:55

Service catalogue

Every component involved in the flows is listed below with its protocols, dependencies, and reference documentation.

Human Customer

Human actor

Delegates tasks to the agent, reviews prompts, and supplies final approval for high-assurance steps.

Protocols:

Web UI, Wallet (QR / deeplink)

Docs:

Redis

Infrastructure

Caching + anti-replay store used by AgentGateway for presentation sessions and AP2 cart state.

Protocols:

TCP 6379

Endpoints:

redis://localhost:6379

Docs:

Issuer · Agent Identity

Issuer / trust

Issues Agent Identity credentials consumed by the wallet mock and verified by AgentGateway.

Protocols:

HTTP, JWT Issuance

Endpoints:

http://localhost:2992

Docs:

Issuer · Proof of Presence

Issuer / trust

Issues proof-of-presence VCs that bind the wallet session to the human during high assurance flows.

Protocols:

HTTP, JWT Issuance

Endpoints:

http://localhost:2991

Docs:

Grafana

Observability

Visualiser for system metrics, traces, and logs; houses system overview dashboards.

Protocols:

HTTPS

Endpoints:

http://localhost:2998

Depends on:

prometheus, tempo, loki

Docs:

Loki

Observability

Aggregates logs forwarded by Promtail, enabling correlated log views in Grafana.

Protocols:

HTTP

Endpoints:

http://localhost:3100

Docs:

OTel Collector

Observability

Receives OTLP metrics/traces/logs from services and fans them out to Prometheus/Tempo/Loki.

Protocols:

OTLP

Docs:

Prometheus

Observability

Scrapes metrics from services including AgentGateway and merchant-agent-a2a.

Protocols:

HTTP, PromQL

Endpoints:

http://localhost:2989

Docs:

Tempo

Observability

OpenTelemetry trace store receiving spans from services via the collector.

Protocols:

OTLP

Endpoints:

http://localhost:3200

Depends on:

otel-collector

Docs:

AgentGateway

Service / API

Verifier and policy engine that issues presentation requests, enforces purchase thresholds, and mints Decision JWTs or AP2 Cart Mandate VCs.

Protocols:

HTTP REST, JWKS, OIDC4VP/DC-API, Prometheus

Endpoints:

http://localhost:2999

Depends on:

redis, issuer-agent-identity, issuer-pop, trust-status-mock

Docs:

MCP HTTP Adapter

Service / API

JSON-RPC adapter exposing AgentGateway tools over HTTP for RP demos.

Protocols:

HTTP, JSON-RPC

Endpoints:

http://localhost:3020/mcp

Depends on:

agentgateway

Docs:

MCP WebSocket Server

Service / API

WebSocket MCP server that calls AgentGateway for presentation requests and decisions on behalf of agents.

Protocols:

WebSocket MCP, HTTP

Endpoints:

ws://localhost:2987/mcp

Depends on:

agentgateway

Docs:

Merchant ACP

Service / API

Agentic Commerce Protocol checkout surface that signs ACP requests, redeems delegated payment tokens, and emits webhooks.

Protocols:

HTTP REST, ACP

Endpoints:

http://localhost:3055

Depends on:

psp-mock

Docs:

Merchant Agent (A2A)

Service / API

AP2-compatible merchant adapter that quotes carts, verifies Cart Mandate VCs, and enforces Trusted Agent Protocol (TAP) signatures before fulfilment.

Protocols:

HTTP REST, A2A/AP2

Endpoints:

http://localhost:3040

Depends on:

agentgateway

Docs:

PSP Mock

Service / API

Delegated payment mock that issues and redeems ACP virtual tokens with signature enforcement.

Protocols:

HTTP REST, ACP

Endpoints:

http://localhost:3050

Docs:

Sample Agent

Service / API

Minimal MCP client that exercises the presentation + introspection APIs through the MCP server.

Protocols:

WebSocket MCP

Depends on:

mcp-server

Docs:

Trust Status Mock

Service / API

Lightweight trust list endpoint that AgentGateway queries to validate external issuers.

Protocols:

HTTP, JSON

Endpoints:

http://localhost:2993

Docs:

Vendor MCP Server

Service / API

Retail MCP tool surface providing search + order placement, validating Decision JWTs, and enforcing Trusted Agent Protocol signatures.

Protocols:

HTTP MCP Tools

Endpoints:

http://localhost:3030

Depends on:

agentgateway

Docs:

Verifier Agent Facade

Service / API

Thin façade (HTTP/MCP) that brokers external verifier requests to AgentGateway using standardised protocols.

Protocols:

HTTP, MCP

Depends on:

agentgateway

Docs:

Wallet Mock

Service / API

DC-API / OIDC4VP simulator that fulfils presence prompts by issuing Agent Identity + PoP credentials and AP2 signatures.

Protocols:

HTTP, DC-API, OIDC4VP

Endpoints:

http://localhost:2984

Depends on:

agentgateway, issuer-agent-identity, issuer-pop

Docs:

Agent UI

UI surface

Next.js chat surface that drives the MCP client, renders QR codes, and orchestrates MCP or AP2 purchase flows.

Protocols:

HTTPS, MCP Client, Fetch API

Endpoints:

http://localhost:5175

Depends on:

agentgateway, wallet-mock, vendor-mcp, merchant-agent-a2a, merchant-acp, psp-mock

Docs:

Gateway Console

UI surface

Policy management UI for AgentGateway; configures purchase thresholds and inspects decisions/JWKS.

Protocols:

Next.js, REST API

Endpoints:

http://localhost:5180

Depends on:

agentgateway

Docs:

RP Next

UI surface

Relying-party Next.js app demonstrating how to request wallet proofs through the MCP HTTP adapter.

Protocols:

Next.js, HTTP

Endpoints:

http://localhost:2985

Depends on:

mcp-http-adapter, agentgateway

Docs:

SSE Dashboard

UI surface

Simple dashboard that streams live server-sent events from the stack.

Protocols:

HTTP, SSE

Endpoints:

http://localhost:8080

Docs:

Vendor Site

UI surface

Static storefront that mirrors the MCP catalog for demos; powered by vendor-mcp for live data.

Protocols:

HTTPS

Endpoints:

http://localhost:5176

Depends on:

vendor-mcp

Docs: