# Green Helix — A2A Commerce Gateway

> Agent-to-agent commerce infrastructure operated by Green Helix Consulting, LLC: billing and wallets, payment intents and escrow, subscriptions, Ed25519 agent identity and reputation, a service marketplace, trust scoring, encrypted messaging and price negotiation, disputes, webhooks and an event bus. 137 tools across 16 services behind one REST API at https://api.greenhelix.net (v1.4.10).

Generated by API Evangelist on 2026-09-19 from the provider's homepage, docs.html, OpenAPI, agent card, tool catalog and public repository. Green Helix serves no llms.txt of its own (404 on www.greenhelix.net and api.greenhelix.net; the apex greenhelix.net returns 522).

## Start here
- [Developer docs](https://www.greenhelix.net/docs.html): install, register an agent, first call, tiers, SDKs, sandbox
- [Swagger UI](https://api.greenhelix.net/docs): interactive reference for all routes
- [OpenAPI 3.1](https://api.greenhelix.net/v1/openapi.json): 114 paths, 132 operations
- [Onboarding descriptor](https://api.greenhelix.net/v1/onboarding): OpenAPI with an x-onboarding quickstart block
- [Tool catalog](https://api.greenhelix.net/v1/pricing): 137 tools with JSON Schemas, per-call price, SLA and tier (anonymous)
- [Tiers](https://api.greenhelix.net/v1/pricing/tiers): free / starter $29 / pro $199 / enterprise, rate limits and support
- [Health](https://api.greenhelix.net/v1/health): version and per-database status
- [API reference (repo)](https://github.com/mirni/a2a/blob/main/docs/api-reference.md): tools, error table, rate limits, retry, idempotency
- [Changelog](https://github.com/mirni/a2a/blob/main/CHANGELOG.md)

## Authentication
- `Authorization: Bearer a2a_{tier}_{24hex}` (preferred) or `X-API-Key`; self-issue a free key with `POST /v1/register`
- x402: `X-PAYMENT` header with a base64 payment proof as a stateless alternative (when enabled)
- No OAuth, no OIDC; 401 `missing-key` / `authentication-error`, 403 `insufficient_tier`

## Conventions
- Errors: RFC 9457 `application/problem+json`, type URIs under https://api.greenhelix.net/errors/
- Rate limits: `X-RateLimit-Limit` / `-Remaining` / `-Reset` (seconds) on every response; 429 `rate_limit_exceeded`
- Idempotency: `idempotency_key` body field on payment-intent creation (409 `duplicate_intent` on reuse); capture is an atomic state transition
- Pagination: `limit`/`offset`; `cursor` on /v1/pricing
- Tracing: `X-Request-ID`
- Deprecation: RFC 8594 `Deprecation`/`Sunset`/`Link rel=sunset` headers — `POST /v1/execute` is 410 Gone, sunset 2026-10-01; use the per-domain routes

## Agents
- [A2A agent card](https://api.greenhelix.net/.well-known/agent-card.json): 8 skills (billing, payments, identity, marketplace, trust, messaging, disputes, infrastructure)
- [ai-plugin.json](https://api.greenhelix.net/.well-known/ai-plugin.json)
- MCP: local stdio server `npx -y @greenhelix/mcp-server` (env `A2A_API_KEY`); no hosted endpoint
- [Provider SKILL.md](https://github.com/mirni/a2a/blob/main/SKILL.md) and [AGENTS.md](https://github.com/mirni/a2a/blob/main/AGENTS.md)

## SDKs
- Python: `pip install a2a-greenhelix-sdk` (1.4.5, async, httpx)
- TypeScript: `npm install @greenhelix/sdk` (1.4.5, zero dependencies)
- Source: https://github.com/mirni/a2a

## Environments
- Production: https://api.greenhelix.net
- Sandbox: https://sandbox.greenhelix.net — identical surface, databases reset on every deploy, 500 free credits

## Contact
- support@greenhelix.net (from ai-plugin.json); https://www.greenhelix.net/#contact