About tryx402
An open-source SDK and payment gateway layer for AI agents calling x402 and AgentCash endpoints. It adds budget caps, idempotency, cost tracking, planning, and verifiable receipts, with an SDK MCP mode and a separate hosted-account MCP mode.
Key features
- 01Hard spending caps
- 02Idempotent paid calls
- 03USD cost ledger
- 04Estimate workflow costs
- 05Signed payment receipts
- 06Endpoint search and discovery
Use cases
- 01Call paid endpoints within a budget
- 02Prevent duplicate payment for a call
- 03Review spending by origin or account
- 04Estimate a multi-call workflow before execution
MCP support
The SDK MCP server exposes six tools for searching, discovering, calling endpoints, tracking spend, planning, and retrieving receipts. A separate gateway MCP mode adds hosted-account balance, recharge, session, and proxy tools.
Configuration
Local server config is the same for every client. Copy it into your client’s MCP config file.
uvx tryx402GATEWAY_MAX_BUDGET_USDHard session-wide budget cap in USD for all paid calls (e.g. 1.00)TRYX402_API_KEYSecretAPI key for the hosted service (server-side pricing via quote)Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.
Tools
Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.
Details
From the project READMEtryx402 — the OpenRouter for agent payments
MIT licensed. Built in France. The first open-source payment governance layer for AI agents.
A safe, provider-agnostic wrapper over AgentCash / x402. Not limited to prospecting — it drives any endpoint, and adds what AgentCash itself lacks and we learned we need the hard way:
- hard budget caps — stop before overspending
- idempotency — never pay twice for the same call (the $0.83 double-charge lesson)
- cost ledger — USD spent, reconciled, grouped by origin / account
- plan estimation — price a multi-call workflow before spending a single cent
- signed receipts — Ed25519 offline-verifiable proof of every payment
- session tokens + circuit breaker — per-task spend caps with half-open cooldown
- transparent 402→pay→retry — native httpx transport, exactly one retry, no loops
- discovery pipeline — live x402 bazaar indexing (Onyx Bazaar, gold-402)
Open source, no fear
This repo is the open-source SDK: the safe caller, budget guard, idempotency, ledger, CLI and MCP server. MIT licensed.
We don't hide features behind paywalls. We don't split the SDK into "core" and "pro". Everything is here. Use it, fork it, build on it.
The hosted service (https://www.tryx402.app) is the commercial engine:
multi-currency fiat billing, margins, FX, Stripe funding, the verified-tools
catalogue and the provider portal. Pricing is decided server-side via
/v1/quote — a client-side margin is a margin nobody pays.
Revenue model: commission on every pay-per-call transaction routed through the hosted service. The SDK is free. The service takes a cut. That's it.
Positionnement
tryx402 est le premier SDK open source de gouvernance de paiements pour agents IA dans l'écosystème x402. Conçu en France, distribué sous MIT, adopté par la communauté.
Face aux agrégateurs propriétaires (treg.to et consorts), tryx402 défend une position différente : pas de lock-in, pas de licence restrictive, pas de "commercial use only". Le code est libre. La confiance vient du service, pas de la licence.
| Face | Who | Where |\n|---|---|---|\n| Power-tool | you / an agent drive paid endpoints safely | this SDK (gateway.cli, gateway.client) |\n| Fiat gateway | end users pay in their currency, you resell x402 with margin | hosted service (closed) |
Embed it (for agents)
Python — one import:
from gateway import Gateway
gw = Gateway(max_budget_usd=1.0) # safe by default
data = gw.call("https://stable-deepline.dev/api/email/validate",
body={"email": "[email protected]"}, price=0.03)
print(gw.spent_usd) # 0.03
Terminal — one command (like agentcash), after pip install tryx402:
gateway call https://stable-deepline.dev/api/email/validate \
--body '{"email":"[email protected]"}' --price 0.03 --max-budget 0.10
MCP — two modes (pick the one you need):
SDK MCP (pip install) — 6 tools, safe caller only
{
"command": "python3",
"args": ["-m", "tryx402.mcp_server"],
"env": { "TRYX402_MAX_BUDGET_USD": "1.00" }
}
6 tools: gateway_search, gateway_discover, gateway_call, gateway_spent,
gateway_plan, gateway_receipt. Works directly with your x402/AgentCash
crypto wallet — no hosted account needed.
You will NOT see
gateway_check_balance,gateway_recharge,gateway_lookup, orgateway_proxy_callfrompip install tryx402. This is deliberate, not a bug. These tools manage your hosted account credits (funded via Stripe, separate from your crypto wallet). The SDK MCP is a safe x402 caller; the hosted gateway handles the fiat credit layer. For the full 10-tool MCP, see Option B below or connect tohttps://www.tryx402.app/api/mcp.
Gateway MCP (clone repo) — 10 tools, hosted account management
{
"mcpServers": {
"tryx402": {
"command": "python3",
"args": ["-m", "gateway.mcp_server"],
"env": {
"GATEWAY_MAX_BUDGET_USD": "1.00"
}
}
}
}
All 6 SDK tools plus gateway_session, gateway_check_balance,
gateway_recharge, gateway_proxy_call. No API key needed — anonymous
session auth throughout. check_balance / recharge manage your
hosted account credits (funded via Stripe in EUR/USD — not crypto).
Layout
gateway/
├── client.py # SafeClient: any endpoint + budget + idempotency + timeout + ledger
├── ledger.py # cost events, USD/EUR totals, by-origin
├── catalog.py # search(intent) / discover(origin) over the AgentCash catalogue
├── api.py # Gateway facade: one-import embed + quote() for server pricing
├── cli.py # search / discover / call / quote
└── tests/ # offline: budget, idempotency, on_paid hook, quote client
Use
Discover (free — no payment):
python3 -m gateway.cli search "find work email"
python3 -m gateway.cli discover https://stable-deepline.dev
Call any endpoint safely (spends USDC — budget-capped, idempotent):
python3 -m gateway.cli call https://stable-deepline.dev/api/email/validate \
--body '{"email":"[email protected]"}' --price 0.03 --max-budget 0.10
Ask the hosted service what a call costs your account (server-side FX + margin):
export TRYX402_API_KEY="gw_..." # from https://www.tryx402.app
gateway quote 0.04
# -> {"account":"acme","currency":"EUR","charge_minor":5,"charge":"0.05 EUR"}
What's real vs hosted
- Real (this SDK): the safe caller, budget cap, idempotency, cost ledger, catalogue search/discover.
- Hosted: accounts, balances, fiat funding (Stripe), FX conversion, margins — all decided by the server; the SDK only asks with
quote(). - Deliberately off: auto-retry of paid calls (default
max_retries=0) — retrying a possibly-paid call is what double-charged us; opt in only if the server honors theIdempotency-Keyheader.
Telemetry (optional)
tryx402 sends one anonymous ping on first import to help us understand usage: install-id (random, persisted locally), package version, Python version, platform.
No PII. No tracking across sites. No personal data.
Disable it anytime:
export TRYX402_NO_TELEMETRY=1
Or set an empty URL to disable:
export TRYX402_TELEMETRY_URL=""
Comments
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.