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io.fairseal/mcp-server

Official registry Games, sports and entertainment

Verifiable entropy, provably-fair games, and receipt verification for AI agents (FairSeal API).

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package @fairseal/mcp-server
Claude Code 
claude mcp add io-fairseal-mcp-server -e 'FAIRSEAL_API_KEY=<your fairseal_api_key>' -e 'FAIRSEAL_API_URL=<FAIRSEAL_API_URL>' -e 'FAIRSEAL_NOTARY_API_KEY=<your fairseal_notary_api_key>' -e 'FAIRSEAL_ANCHOR_API_KEY=<your fairseal_anchor_api_key>' -- npx -y @fairseal/mcp-server@0.2.4
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "io-fairseal-mcp-server": {
            "command": "npx",
            "args": [
                "-y",
                "@fairseal/mcp-server@0.2.4"
            ],
            "env": {
                "FAIRSEAL_API_KEY": "<your fairseal_api_key>",
                "FAIRSEAL_API_URL": "<FAIRSEAL_API_URL>",
                "FAIRSEAL_NOTARY_API_KEY": "<your fairseal_notary_api_key>",
                "FAIRSEAL_ANCHOR_API_KEY": "<your fairseal_anchor_api_key>"
            }
        }
    }
}

Environment variables

  • FAIRSEAL_API_KEY secret API key for gated tools (fairseal_entropy, fairseal_stats, fairseal_rng_generate, fairseal_notarize_decision, fairseal_anchor_submit). Key prefix: fsn_. Without a key these tools return 401; free tools (game reads, notarize_status, anchor_status) work without any key. x402 micropayment ($0.02 USDC on Base) is an alternative to the key for notarize/anchor.
  • FAIRSEAL_API_URL Upstream API base URL (default https://api.fairseal.io).
  • FAIRSEAL_NOTARY_API_KEY secret Key override for the notary service only (POST /v1/notarize). Falls back to FAIRSEAL_API_KEY if not set. Key prefix: fsn_.
  • FAIRSEAL_ANCHOR_API_KEY secret Key override for Anchor API v2 only (POST /v2/anchor). Falls back to FAIRSEAL_API_KEY if not set. Key prefix: anck_.

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. Fairseal 🦭
  2. Try It Now
  3. Quick Start
  4. How It Works
  5. Performance
  6. Packages
  7. Use Cases
  8. Result Notarization vs. Activity Receipts
  9. Links
  10. Listings
  11. License

Fairseal 🦭

Provably fair selections for games, loot boxes, and any randomized allocation.

Fairseal creates verifiable receipts (CSRs) proving that a selection was committed before the outcome was knowable. Every loot drop, gacha pull, and randomized selection — independently verifiable, trustlessly.

Try It Now

npx @fairseal/commit

One command. A verifiable gacha pull in your terminal. No setup.

Quick Start

npm install @fairseal/commit
import { createCommitment, resolveCommitment, createReceipt, verifyReceipt } from '@fairseal/commit';

// 1. Lock your loot table BEFORE the outcome is knowable
const commitment = createCommitment({
  rule: JSON.stringify(LOOT_TABLE),
  inputs: [playerId, pullNumber.toString()],
  revealAfter: 10,
});

// 2. Resolve with verifiable entropy from drand
const resolution = await resolveCommitment(commitment);

// 3. Your algorithm + verifiable entropy = provably fair drop
const drop = yourWeightedPull(LOOT_TABLE, resolution.beaconRandomness);

// 4. Package as a receipt anyone can verify
const receipt = createReceipt(commitment, resolution);
const proof = await verifyReceipt(receipt); // ✅ PARTIAL

How It Works

  1. Commit — Lock your drop table + player ID into a hash before the randomness exists
  2. Entropy — Wait for a public drand beacon round (Cloudflare + Protocol Labs)
  3. Resolve — Derive the selection from beacon entropy + your committed rule
  4. Verify — Anyone can re-run every step. drand beacon signatures are BLS12-381-verified; FairSeal receipt signatures use EIP-191 (secp256k1) / Ed25519 — receipts are never BLS-signed. No trust required.

Performance

OperationTime
Commitment creation0.006ms (170,000+/sec)
Beacon fetch~200ms
drand beacon verification (BLS12-381)~150ms
Receipt size0.9 KB

Client-side. No server. No account. No fees for PARTIAL verification.

Packages

PackageDescription
@fairseal/gameGame API for RGS studios. Slots, gacha, loot boxes. (v0.1 ALPHA)
@fairseal/commitCommitted selection receipts. Core library.
@fairseal/coreCryptographic primitives, signing, Merkle trees.
@fairseal/verifyIndependent receipt verification.
@fairseal/mcp-serverMCP server for AI agents. Verifiable entropy, provably-fair games, cryptographic receipt verification via Model Context Protocol.

Use Cases

ScenarioHow
Gacha / loot boxEvery pull has a receipt. Players verify drops match published rates.
Boss loot dropsDrop table committed per encounter. No ninja-nerfing.
MatchmakingPairing algorithm committed. Players verify no favoritism.
Tournament bracketsSeeding provably random, not rigged.
NFT mint orderQueue provably fair — no insider front-running.
Slot machinesSeed Commitment Model — verifiable spins, no nonce chain.

Result Notarization vs. Activity Receipts

Most "agent receipts" today are activity receipts: the platform logs what an agent did, and you trust whoever wrote the log. Fairseal receipts are result notarization — a different trust model:

Activity receipts (platform logs)Fairseal result notarization
Who do you trust?The operator writing the logNo one — receipts verify offline
What is proven?That an action was recordedThat a result was committed before the outcome was knowable
Time proofServer timestamp (operator-controlled)External anchor on Base (independently checkable)
Tamper evidenceDepends on log integrityHash-anchored; any modification breaks verification

Related standards: payment-authorization protocols like Google/Mastercard AP2 (mandates), Visa TAP, and OpenAI/Stripe ACP prove that an agent may act and who it is. Fairseal proves what happened — that a result was committed and hasn't been altered since. Fairseal settles micropayments over Coinbase's x402 and does not implement AP2/TAP/ACP; the layers are complementary.

Listings

License

MIT — Fairseal

Frequently asked questions

What is io.fairseal/mcp-server?

Verifiable entropy, provably-fair games, and receipt verification for AI agents (FairSeal API).

How do I install io.fairseal/mcp-server?

It runs on your machine. In Claude Code: claude mcp add io-fairseal-mcp-server -e 'FAIRSEAL_API_KEY=<your fairseal_api_key>' -e 'FAIRSEAL_API_URL=<FAIRSEAL_API_URL>' -e 'FAIRSEAL_NOTARY_API_KEY=<your fairseal_notary_api_key>' -e 'FAIRSEAL_ANCHOR_API_KEY=<your fairseal_anchor_api_key>' -- npx -y @fairseal/mcp-server@0.2.4. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.fairseal/mcp-server need an API key?

Yes. It expects FAIRSEAL_API_KEY, FAIRSEAL_NOTARY_API_KEY, FAIRSEAL_ANCHOR_API_KEY, which you set in its configuration.

Is io.fairseal/mcp-server open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains io.fairseal/mcp-server?

It is published by ned-del. AI.tn lists it but does not maintain or endorse it.

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