feat(samples): add human-present crypto-algo scenario (AP2 v0.1 + AlgoVoi on-chain USDC extension) by chopmob-cloud · Pull Request #218 · google-agentic-commerce/AP2

chopmob-cloud · 2026-04-13T21:15:23Z

Summary

Adds a new human-present scenario demonstrating on-chain USDC payment via the
AP2 crypto-algo/v1 extension on Algorand and VOI.

New scenario folder: samples/python/scenarios/a2a/human-present/crypto-algo/
README.md — full walkthrough matching the style of the cards and x402 scenarios
run.sh — one-command startup script matching the pattern of cards/run.sh

What this demonstrates

The crypto-algo/v1 extension (published at https://api1.ilovechicken.co.uk/ap2/extensions/crypto-algo/v1) defines:

PaymentMethodData — network, receiver, amount_microunits, asset_id, min_confirmations, memo_required
PaymentResponseDetails — network, tx_id, note_field

The scenario covers the full human-present flow:

Merchant Agent issues a CartMandate with crypto-algo/v1 in payment_methods
Credentials Provider submits on-chain USDC (Algorand or VOI)
note_field = sha256(CartMandate) — cryptographically binds payment proof to the approved cart (addresses the binding gap discussed in issue [Security Hardening Suggestion]AP2 Human-Present: CartMandate ↔ PaymentMandate Binding and Verification Gap #211)
Shopping Agent signs a PaymentMandate with the payer's ed25519 key
Merchant Payment Processor verifies signature + note_field hash, then confirms on-chain via public indexer

Reference implementation

A complete open-source server-side gate (Ap2Gate) is available at
AlgoVoi-Platform-Adapters/ap2-adapter/ —
81/81 tests, zero pip dependencies, 4-chain smoke tested (Algorand, VOI, Hedera, Stellar — 13 April 2026).

Chain support

Network	Asset	Ticker
`algorand-mainnet`	ASA 31566704	USDC
`voi-mainnet`	ARC200 302190	aUSDC

Test plan

README.md renders correctly and matches style of existing scenarios
run.sh follows the same startup pattern as cards/run.sh
Extension URI resolves: https://api1.ilovechicken.co.uk/ap2/extensions/crypto-algo/v1
Schema resolves: https://api1.ilovechicken.co.uk/ap2/extensions/crypto-algo/v1/schema.json

Note: Google CLA must be signed before this PR can be merged — see CONTRIBUTING.md.

🤖 Generated with Claude Code

…oVoi extension)

google-cla · 2026-04-13T21:15:36Z

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gemini-code-assist

Code Review

This pull request introduces a bash script to automate the execution of the crypto-algo AP2 example, handling environment setup, virtual environment management via uv, and the orchestration of background agent processes. The review feedback suggests refining the web interface command to target the specific shopping agent directory, removing a redundant installation step that is already covered by uv sync, and improving the robustness of the log-clearing logic by using find instead of shell wildcards.

gemini-code-assist · 2026-04-13T21:16:47Z

+echo "All remote servers are starting."
+
+echo "Starting the Shopping Agent..."
+$UV_RUN_CMD --package ap2-samples adk web --host 0.0.0.0 $AGENTS_DIR


The log message on line 109 indicates that the 'Shopping Agent' is being started. However, $AGENTS_DIR points to the parent directory containing multiple agents (merchant, credentials provider, etc.). To ensure the web interface targets the shopping agent specifically, it is recommended to point adk web directly to the shopping_agent subdirectory.

Suggested change

$UV_RUN_CMD --package ap2-samples adk web --host 0.0.0.0 $AGENTS_DIR

$UV_RUN_CMD --package ap2-samples adk web --host 0.0.0.0 $AGENTS_DIR/shopping_agent

gemini-code-assist · 2026-04-13T21:16:48Z

+echo "Virtual environment activated."
+
+echo "Installing project in editable mode..."
+uv pip install -e .


The command uv pip install -e . is redundant because uv sync (called on line 71) already handles installing the project and its dependencies in the virtual environment. Removing this line simplifies the script and follows uv best practices.

gemini-code-assist · 2026-04-13T21:16:48Z

+if [ -d "$LOG_DIR" ]; then
+  rm -f "$LOG_DIR"/*
+fi


Clearing the log directory using a wildcard * can be problematic if the directory is empty (the wildcard might not expand) or contains a very large number of files. A more robust approach is to use find to delete the contents without relying on shell expansion.

Suggested change

if [ -d "$LOG_DIR" ]; then

rm -f "$LOG_DIR"/*

fi

if [ -d "$LOG_DIR" ]; then

find "$LOG_DIR" -mindepth 1 -delete

fi

chopmob-cloud · 2026-04-14T17:35:46Z

I have signed the Google CLA. @googlebot please re-check.

- Remove redundant `uv pip install -e .` (uv sync already covers it) - Use `find -mindepth 1 -delete` for log clearing (safer than wildcard) - Point `adk web` at $AGENTS_DIR/shopping_agent subdirectory

chopmob-cloud

Thanks for the review @gemini-code-assist. All three suggestions are already applied in the latest commit:

adk web now points to $AGENTS_DIR/shopping_agent specifically
uv pip install -e . removed (uv sync handles it)
Log clearing uses find "$LOG_DIR" -mindepth 1 -delete for robustness

chopmob-cloud · 2026-04-15T16:41:05Z

Thanks for the review @gemini-code-assist — all three suggestions are already applied in the latest commit:

adk web now targets $AGENTS_DIR/shopping_agent specifically
uv pip install -e . removed (covered by uv sync)
Log clearing uses find "$LOG_DIR" -mindepth 1 -delete

gemini-code-assist · 2026-04-15T16:41:21Z

Thanks for the update, @chopmob-cloud. The changes look good and address the points raised. I'll take another look at the PR now.

chopmob-cloud · 2026-04-20T21:10:46Z

Live demo: AP2 over A2A v1.0 REST + MCP

Following up on the adapter — wanted to share a working end-to-end demonstration of the protocol stack this implements:

AI Agent (Claude/Cursor/etc.)
    │  MCP tool call: send_a2a_message(agent_url, text)
    ▼
AlgoVoi MCP Server  ─────────────────────────────────────────
    │  POST https://agent.example.com/message:send
    ▼
A2A v1.0 REST server
    │  HTTP 402  X-AP2-Cart-Mandate: ...
    │            X-AP2-Payment-Required: amount=0.01,network=algorand_mainnet
    ▼
Agent pays on-chain (Algorand / VOI / Hedera / Stellar)
    │  Retry with  Authorization: Payment <tx_id>
    ▼
A2A v1.0 REST server  →  task result returned

AP2 v0.1 (CartMandate / PaymentMandate) is one of three payment challenge protocols the adapter supports over the A2A v1.0 REST transport — alongside MPP (WWW-Authenticate) and x402 (X-Payment-Required).

MCP tools (v1.2.0)

The AlgoVoi MCP Server now ships two A2A client tools that complete this flow from inside any MCP-compatible assistant:

Tool	What it does
`fetch_agent_card`	`GET {agent_url}/.well-known/agent.json` — discover capabilities + payment requirements
`send_a2a_message`	`POST {agent_url}/message:send` — call payment-gated A2A agent; returns task on 200, `challenge_headers` on 402 for pay-and-retry

Live smoke test results

═══════════════════════════════════════════════════════════
  MCP A2A Two-Agent Smoke Test
  Agent A: AlgoVoi MCP tools
  Agent B: https://api1.ilovechicken.co.uk
═══════════════════════════════════════════════════════════

Phase 1a — fetch_agent_card
  ✓  tool returned without exception
  ✓  agent_url matches
  ✓  error is None
  ✓  card.name present
  ✓  card.description present
  ✓  card.url present
  ✓  card has skills list
  ✓  card has securitySchemes

Phase 1b — send without payment (expect 401/402)
  ✓  tool returned without exception
  ✓  401 Unauthorized returned (auth required before payment check)

Phase 1c — generate AP2/MPP challenge (4-network)
  ✓  status_code == 402
  ✓  WWW-Authenticate set
  ✓  accepts has 4 networks

PASS  13/13 checks passed

npm: npx -y @algovoi/mcp-server
PyPI: pip install algovoi-mcp
Source + smoke test: https://github.com/chopmob-cloud/AlgoVoi-MCP-Server

chopmob-cloud · 2026-04-22T18:45:08Z

Update — Base chain support + ecosystem status (2026-04-22)

Since the last update AlgoVoi now supports Base (EVM) as a fifth payment network alongside Algorand, VOI, Hedera, and Stellar. The AP2 scenario in this PR can be extended to cover Base/USDC payment flows in a follow-up if useful.

Current live status:

Agent card: https://algovoi.co.uk/.well-known/agent.json (lists base_mainnet in skills)
Running ecosystem discovery across 22 A2A seed domains — AlgoVoi is currently the only live A2A agent card found across all chains
AP2 + MPP + x402 all live on production with 13/13 smoke tests passing

This PR is MERGEABLE with CLA signed and all gemini-code-assist suggestions addressed. Gentle ping for human maintainer review — no changes needed on our side. 🙏

chopmob-cloud added 2 commits April 13, 2026 22:14

feat(samples): add crypto-algo human-present scenario (AP2 v0.1 + Alg…

183ac75

…oVoi extension)

feat(samples): add crypto-algo run.sh

f5bb283

chopmob-cloud requested a review from a team as a code owner April 13, 2026 21:15

chopmob-cloud mentioned this pull request Apr 13, 2026

[Security Hardening Suggestion]AP2 Human-Present: CartMandate ↔ PaymentMandate Binding and Verification Gap #211

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gemini-code-assist Bot reviewed Apr 13, 2026

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chopmob-cloud mentioned this pull request Apr 14, 2026

feat: add AlgoVoi wallet provider TxnLab/use-wallet#434

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4 tasks

chopmob-cloud added 3 commits April 14, 2026 19:01

fix(samples): address Gemini Code Assist review on crypto-algo run.sh

b4480c9

- Remove redundant `uv pip install -e .` (uv sync already covers it) - Use `find -mindepth 1 -delete` for log clearing (safer than wildcard) - Point `adk web` at $AGENTS_DIR/shopping_agent subdirectory

fix(ci): set executable bit on run.sh (BASH_EXEC lint)

d9cbafb

fix: add ALGOVOI and AlgoVoi to cspell wordlist

6002d73

chopmob-cloud force-pushed the feat/crypto-algo-scenario branch from bfac829 to 6002d73 Compare April 14, 2026 18:02

chopmob-cloud commented Apr 15, 2026

View reviewed changes

chopmob-cloud mentioned this pull request Apr 24, 2026

feat(samples): add human-present crypto-solana scenario (AP2 + Solana Pay reference binding) #228

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feat(samples): add human-present crypto-algo scenario (AP2 v0.1 + AlgoVoi on-chain USDC extension)#218

feat(samples): add human-present crypto-algo scenario (AP2 v0.1 + AlgoVoi on-chain USDC extension)#218
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	$UV_RUN_CMD --package ap2-samples adk web --host 0.0.0.0 $AGENTS_DIR
	$UV_RUN_CMD --package ap2-samples adk web --host 0.0.0.0 $AGENTS_DIR/shopping_agent

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chopmob-cloud commented Apr 13, 2026

Summary

What this demonstrates

Reference implementation

Chain support

Test plan

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Live demo: AP2 over A2A v1.0 REST + MCP

MCP tools (v1.2.0)

Live smoke test results

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