com.blackwalltier/blackwall-x402-guardrail
Keyless hosted MCP: pre-signature x402 payment verdict (GO/HOLD/STOP) with a signed receipt.
Open source Repository Open in the app JSON README (API)
About
Keyless hosted MCP: pre-signature x402 payment verdict (GO/HOLD/STOP) with a signed receipt.
Details
- Kind
- MCP servers
- Topic
- Finance & crypto
- Publisher
- com.blackwalltier
- Origin
- official
- Category
- ferramentas
- Transport
- http
- Version
- 0.1.2
- Last push
- 2026-08-25T04:41:18Z
- Repository state
- ativo
- Language
- JavaScript
- Added
- 2026-08-29 03:01:00
- Updated
- 2026-08-29 03:01:00
- Origin id
com.blackwalltier/blackwall-x402-guardrail
README
# Black_Wall remote MCP A hosted **remote MCP** (Model Context Protocol over HTTP) that gives any MCP-capable agent a pre-signature **payment-risk verdict** — with no install and no signup. Add one URL and your agent can ask, before it signs an x402 payment, *"should I pay this?"* and get **GO / HOLD / STOP** — from counterparty settlement reputation, price-anomaly (quoted vs the payee's own median), and OFAC sanctions — plus a **third-party-verifiable Ed25519 signed receipt**. ## Add it Point your MCP client at: ``` https://mcp.blackwalltier.com ``` Transport: **Streamable HTTP**. No API key. Verdicts for amounts **under $10 at risk are free**; at or above that, the tool returns an **x402 payment challenge** your agent settles from its own wallet (pass the settled payment back as an `X-PAYMENT` header, then retry). ## The tool: `forecast_payment` | field | | | |---|---|---| | `counterparty` | string, required | recipient wallet from the 402 | | `amount` | string, required | decimal string, e.g. `"0.09"` | | `asset` | string, required | e.g. `USDC` | | `chain` | string, required | e.g. `base` | | `payer` / `resource` / `agent_id` / `context` | optional | binds settlement / context | Returns a verdict (`GO`/`HOLD`/`STOP`) + reasons + signals, and a `signed_receipt` anyone can verify against the published key at `https://agent-egress-proxy.onrender.com/.well-known/blackwall-receipt-key.json` (any RFC 8032 Ed25519 library) — Black_Wall never has to be in the loop. ## How it works This Worker is a **thin transport + proxy**: it speaks minimal MCP JSON-RPC (`initialize` / `tools/list` / `tools/call` / `ping`) and forwards `forecast_payment` calls to the Black_Wall x402 oracle. All decision logic and the receipt come from the oracle unchanged. **Fail-closed by design:** if the oracle errors, is unreachable, or returns a non-verdict, the tool returns an error — **never a phantom `GO`**. A payment guardrail that can't reach its backend must not imply "safe to pay." ## Registry Published to the official MCP Registry as `com.blackwalltier/blackwall-x402-guardrail`. ## Develop ```sh node test.mjs # unit tests (mocked oracle) npx wrangler dev # run locally npx wrangler deploy # deploy (Cloudflare Workers) ``` By BlueTier. Verdict only — never takes custody, never in the settlement path. *No evidence is not trust.*