XGuard MCP Server

XGuard — Universal Paid AI Agent + Secretless Gateway

Canonical production API

https://api.xguardgate.com

Canonical identity — v5.1.0: XGuard Universal Paid AI Agent + Secretless Gateway. Agents discover real tools, get a signed price, pay per request through x402 v2 USDC, and receive a signed receipt plus ProofRail evidence. Secretless Egress keeps reusable upstream credentials outside agent context. See CANONICAL_IDENTITY.md.

The primary no-account path is:

discovery → capabilities → preflight → signed quote → HTTP 402 → verify + settle
          → controlled execution → signed receipt + ProofRail

The first paid production tool is xguard.web.fetch: bounded public HTTPS GET/HEAD with SSRF protection, public-DNS validation, safe manual redirects, content/type/size/time limits, caching, stable errors, source timestamps and content hashes. Search, AI generation/routing and data-query tools are explicitly disabled until real connectors are configured.

Five-minute quickstart

No account or SDK is needed to discover the service, inspect pricing, obtain a signed quote, and receive the standard x402 challenge:

curl -sS https://api.xguardgate.com/v1/capabilities
curl -sS https://api.xguardgate.com/v1/pricing

# Optional free guard: validates HTTPS/SSRF/DNS/payment readiness without contacting the target
curl -sS https://api.xguardgate.com/v1/preflight \
  -H 'content-type: application/json' \
  -d '{"url":"https://example.com/","testnet":true}'

curl -sS https://api.xguardgate.com/v1/pricing/quote \
  -H 'content-type: application/json' \
  -d '{"url":"https://example.com/","testnet":true}'

# Send the returned compact `quote` as X-XGuard-Quote. The response is HTTP 402
# with PAYMENT-REQUIRED and a signed offer until PAYMENT-SIGNATURE is supplied.
curl -i https://api.xguardgate.com/v1/tools/web.fetch/testnet \
  -H 'content-type: application/json' \
  -H 'X-XGuard-Quote: <signed-quote>' \
  -d '{"url":"https://example.com/"}'

The final payment payload is standard x402 v2; it can be produced by any compatible wallet/client. XGuard additionally requires the server-recommended payment-identifier returned in the quote and challenge. An exact retry returns the stored result and does not settle twice.

MCP

curl -sS https://api.xguardgate.com/mcp \
  -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"xguard.pricing.quote","arguments":{"url":"https://example.com/","testnet":true}}}'

A2A

curl -sS https://api.xguardgate.com/a2a \
  -H 'content-type: application/json' -H 'a2a-version: 1.0' \
  -d '{"jsonrpc":"2.0","id":1,"method":"SendMessage","params":{"message":{"messageId":"discover-1","role":"ROLE_USER","parts":[{"text":"discover XGuard"}]}}}'

TypeScript and Python discovery

const capabilities = await fetch("https://api.xguardgate.com/v1/capabilities").then(r => r.json());
const quote = await fetch("https://api.xguardgate.com/v1/pricing/quote", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ url: "https://example.com/", testnet: true }),
}).then(r => r.json());

import requests

capabilities = requests.get("https://api.xguardgate.com/v1/capabilities", timeout=10).json()
quote = requests.post(
    "https://api.xguardgate.com/v1/pricing/quote",
    json={"url": "https://example.com/", "testnet": True},
    timeout=10,
).json()

Canonical discovery surfaces: /mcp, /a2a, /.well-known/agent-card.json, /.well-known/payment-manifest, /.well-known/x402-facilitator.json, /openapi.json, /llms.txt, /v1/capabilities, /v1/preflight, /v1/pricing, /v1/health, and /v1/ready.

xguard.preflight is the free guard at the front door: it gives an agent a deterministic allow/block decision and the exact quote URL before any upstream request or payment. xguard.web.fetch is the mandatory guarded execution choke point; every paid call requires a signed quote and x402 v2 settlement before the target is contacted. When an operator keeps a reusable upstream credential only in XGuard, Secretless Egress is likewise the required credential-backed path for that environment.

Secretless credential path

XGuard keeps reusable upstream credentials out of AI agents. Operators store a Stripe, GitHub, OpenAI, Anthropic, Slack, Notion, Cloudflare, Gemini or custom API credential once, then give the agent only a short-lived scoped XGuard capability.

Operator secret
     ↓
Encrypted XGuard credential vault
     ↓
Scoped capability
     ↓
AI agent
     ↓
XGuard Secretless Egress
     ↓
credential injected server-side
     ↓
upstream API

The agent never receives the reusable upstream credential.

XGuard becomes an actual choke point when an operator keeps the reusable credential only in XGuard and delegates capabilities instead of redistributing that credential. XGuard does not claim control over unrelated Internet traffic.

Why Secretless Egress

A reusable bearer token inside an autonomous agent can be copied, logged, placed in context, reused outside the intended request or leaked to an untrusted tool. XGuard changes the primitive from secret possession to scoped capability possession.

The current egress boundary provides:

• encrypted reusable credential storage;
• provider presets for OpenAI, Anthropic, GitHub, Stripe, Slack, Notion, Cloudflare and Gemini;
• custom header-based credentials restricted to explicit public HTTPS hosts;
• short-lived capabilities;
• exact HTTPS origin binding;
• path-prefix allowlists;
• HTTP method allowlists;
• maximum call counts;
• Usage Credit billing before secret release and before outbound network egress;
• no automatic credential forwarding across redirects;
• private/local target blocking;
• automatic Idempotency-Key injection for unsafe methods;
• no blind automatic replay after network ambiguity;
• MCP discovery and egress execution without exposing credential provisioning to model context.

Egress API

Machine-readable contract:

GET https://api.xguardgate.com/v1/egress
GET https://api.xguardgate.com/.well-known/xguard-egress.json
GET https://api.xguardgate.com/.well-known/xguard-egress-key.json
GET https://api.xguardgate.com/v1/egress/providers

1. Operator stores a reusable credential

Credential provisioning is intentionally an operator API, not an MCP tool.

POST /v1/egress/credentials
X-XGuard-Key: <usage-credit-key>
Content-Type: application/json

{
  "provider": "github",
  "value": "<github-token>",
  "label": "production-github",
  "allowed_paths": ["/repos/"],
  "allowed_methods": ["GET", "POST"]
}

XGuard returns only credential metadata such as xcred_...; the reusable secret is not returned.

2. Operator issues a short capability

POST /v1/egress/capabilities
X-XGuard-Key: <usage-credit-key>
Content-Type: application/json

{
  "credential_id": "xcred_...",
  "target_origin": "https://api.github.com",
  "path_prefix": "/repos/",
  "allowed_methods": ["GET", "POST"],
  "ttl_seconds": 300,
  "max_calls": 10
}

The returned xgc_... capability is what the agent receives.

3. Agent executes without the upstream secret

POST /v1/egress/fetch
Content-Type: application/json

{
  "capability": "xgc_...",
  "target": "https://api.github.com/repos/org/repo/issues",
  "method": "POST",
  "body_json": {
    "title": "Example"
  }
}

XGuard validates capability scope and billing, injects the GitHub credential server-side, sends one HTTPS request and never exposes the reusable GitHub token to the agent.

Pricing contract:

GET /v1/egress/pricing

The current configuration consumes 1 XGuard Usage Credit per authorized credential-backed egress attempt. Billing is committed before credential decryption and before outbound network egress. If billing cannot commit, no upstream request is sent.

MCP

Canonical MCP endpoint:

https://api.xguardgate.com/mcp

Agent-facing tools include:

xguard_secretless_egress
xguard_egress_fetch
xguard_action_rail

Reusable credential creation is deliberately not exposed as an MCP tool.

Action Rail underneath

The no-account paid-tool path and Secretless Egress are the primary product boundaries. XGuard Action Rail remains available underneath for stronger execution controls around payments, purchases, bookings, messages, deployments, deletes, API writes and tool calls.

POST /v1/mandates
POST /v1/actions/permits
POST /v1/actions/execute
GET  /v1/actions/permits/{permit_id}

Action Rail adds scoped mandates, request-bound cryptographic permits, replay rejection, durable execution state and receipts.

Universal and Edge deployment

For operator-controlled infrastructure XGuard can also be placed in front of an origin:

Internet / Ingress
      ↓
XGuard Universal Gate
      ↓
private origin

The repository includes Cloudflare Edge Gate, portable Node deployment, Docker, Docker Compose, Kubernetes and OpenAPI AutoGate components.

Native x402 and paid execution

x402 v2 is the primary no-account payment path for paid agent tools. XGuard also retains its facilitator relay endpoints for backwards compatibility.

GET  /supported
POST /verify
POST /settle
GET  /facilitator
GET  /.well-known/x402
GET  /v1/facilitator/route

XGuard remains a non-custodial x402 v2 facilitator gateway with capability-aware routing, replay protection, Base USDC reconciliation and fail-closed ambiguous settlement behavior.

Security model

• reusable upstream credentials are encrypted at rest using per-record AES-GCM keys wrapped by an XGuard RSA-OAEP authority;
• secret values are not included in agent capabilities;
• operator XGuard Usage Credit keys are encrypted into capability state and are not handed to agents;
• capabilities bind an origin, path prefix, methods, expiry and maximum calls;
• user-supplied headers cannot override the injected credential header or XGuard control headers;
• private/local targets and XGuard self-targets are blocked;
• redirects are not automatically followed with injected credentials;
• billing commits before secret decryption and network egress;
• unsafe methods receive an XGuard-generated Idempotency-Key when the caller did not supply one;
• XGuard does not automatically replay a credential-backed request after a network ambiguity.

Machine discovery

GET /.well-known/xguard-egress.json
GET /.well-known/xguard-actions.json
GET /.well-known/xguard.json
GET /.well-known/ai-plugin.json
GET /.well-known/agent-card.json
GET /architecture
GET /v1/protocols
GET /openapi.json
GET /llms.txt
GET /skill.md
GET /sitemap.xml

Production domains

https://xguardgate.com
https://api.xguardgate.com

The Cloudflare Worker configuration disables the public workers.dev route so XGuard's production identity is limited to the custom XGuard domains.

Repository:

https://github.com/moelayyan90/XGuard