Fairseal

io.fairsealPublished by fairseal.iov0.2.4Updated Nov 4, 2026

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

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Overview

AI-generated overview

FairSeal MCP server gives an assistant verifiable entropy, provably-fair selection receipts, and cryptographic receipt verification through the FairSeal API.

What you can do
  • Generate verifiable randomness and entropy from public drand beacon rounds
  • Commit randomized selections and resolve them against committed rules
  • Create, notarize and anchor result receipts so a result is provably fixed before the outcome was known
  • Verify receipts offline and retrieve usage statistics
  • Submit anchors to an external chain for independent time proof
When to use it
Use it when an assistant needs to make or audit randomized allocations that someone else must be able to check afterwards: gacha pulls, loot drops, matchmaking, tournament seeding, mint order, or any result that should be provably committed before it was known.
Requirements
Runs locally over stdio, typically via the npm package @fairseal/mcp-server. Gated tools need an API key in FAIRSEAL_API_KEY; optional overrides FAIRSEAL_ANCHOR_API_KEY and FAIRSEAL_NOTARY_API_KEY fall back to it. FAIRSEAL_API_URL can point at a different API base. Network access to the FairSeal API and the drand beacon is required.
Before you install
The API keys are secrets and grant access to gated tools; without one those tools return 401. Anchoring and notarization write records to external services and a public chain, and the README mentions settling micropayments over x402, so calls may cost money. Receipts and commitments are submitted to third parties and become publicly checkable.

Installation

In SourceWeft

  1. Open Fairseal in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

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.

[@fairseal/commit] [@fairseal/core] [graded]

Try It Now

bash
npx @fairseal/commit

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

Quick Start

bash
npm install @fairseal/commit
typescript
import { createCommitment, resolveCommitment, createReceipt, verifyReceipt } from '@fairseal/commit';
// 1. Lock your loot table BEFORE the outcome is knowableconst commitment = createCommitment({  rule: JSON.stringify(LOOT_TABLE),  inputs: [playerId, pullNumber.toString()],  revealAfter: 10,});
// 2. Resolve with verifiable entropy from drandconst resolution = await resolveCommitment(commitment);
// 3. Your algorithm + verifiable entropy = provably fair dropconst drop = yourWeightedPull(LOOT_TABLE, resolution.beaconRandomness);
// 4. Package as a receipt anyone can verifyconst 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.

Links

Listings

License

MIT — Fairseal

Source: README.md at commit 8ff9498

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

2
  1. v0.2.4LatestSep 30, 2026
  2. v0.2.3Sep 27, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts