# io.fairseal/mcp-server (npm · @fairseal/mcp-server)

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

- Trust score: 74/100 (medium)
- Change this week: −3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- npm · `@fairseal/mcp-server`: 74/100 (this document), [markdown](https://verifymcp.io/servers/io-fairseal-mcp-server/fairseal-mcp-server.md), [page](https://verifymcp.io/servers/io-fairseal-mcp-server/fairseal-mcp-server)

## Channel facts

- Registry: `npm`
- Package: `@fairseal/mcp-server`
- Version: `0.2.4`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Supply Chain Security**: 98/100
  - No malware found by supply-chain analysis.
  - No known CVEs affecting this package version or its production dependencies.
  - No install/post-install scripts declared.
  - 30 of 92 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 19/100
  - Repository check failed: the declared repository URL redirects; it must resolve directly.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 26 days ago).
  - Disclosure check failed: no security disclosure policy was found in the source repository.
- **Schema Quality & AI Usability**: 73/100
  - AI-judged instruction clarity (good).
  - Tool/resource definitions use about 1243 tokens (~77/item across 16 items; 16 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 80/100
  - Stability observed for 24 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 86/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 59% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 16 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 16 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

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

io.fairseal/mcp-server runs locally as an npm package, launched with npx -y @fairseal/mcp-server. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add io-fairseal-mcp-server -- npx -y @fairseal/mcp-server
```

### Cursor

```json
{
  "mcpServers": {
    "io-fairseal-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fairseal/mcp-server"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "io-fairseal-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fairseal/mcp-server"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add io-fairseal-mcp-server -- npx -y @fairseal/mcp-server
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "io-fairseal-mcp-server": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "@fairseal/mcp-server"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add io-fairseal-mcp-server --command npx --arg -y --arg @fairseal/mcp-server
```

### Hermes

```yaml
mcp_servers:
  io-fairseal-mcp-server:
    command: "npx"
    args: ["-y", "@fairseal/mcp-server"]
```

### Netclaw

```json
{
  "McpServers": {
    "io-fairseal-mcp-server": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "@fairseal/mcp-server"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add io-fairseal-mcp-server -t stdio -c npx -a -y @fairseal/mcp-server
```

### Other

```json
{
  "mcpServers": {
    "io-fairseal-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fairseal/mcp-server"
      ]
    }
  }
}
```

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-05 (score 74, −3)

- [functional] Stability: pass → 0.80

### 2026-10-27 (score 77, 0)

- [security] Stability: 0.97 → pass

### 2026-10-26 (score 77, +1)

No change was recorded against any check on this day. Stability & Change Management went from 93 to 97. That category is still filling its 30-day observation window: 28 days of observed history at the previous scan, 29 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-24 (score 76, +1)

No change was recorded against any check on this day. Stability & Change Management went from 87 to 90. That category is still filling its 30-day observation window: 26 days of observed history at the previous scan, 27 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-22 (score 75, +1)

No change was recorded against any check on this day. Stability & Change Management went from 80 to 83. That category is still filling its 30-day observation window: 24 days of observed history at the previous scan, 25 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-20 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 73 to 77. That category is still filling its 30-day observation window: 22 days of observed history at the previous scan, 23 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-17 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 63 to 67. That category is still filling its 30-day observation window: 19 days of observed history at the previous scan, 20 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-15 (score 72, +1)

No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (16)

### `fairseal_entropy` (~39 tokens)

Get verifiable entropy

Fetch raw verifiable entropy from the latest resolved VDF epoch at api.fairseal.io. Read-only. [requires FAIRSEAL_API_KEY]

### `fairseal_games_catalog` (~37 tokens)

List FairSeal games

List available provably-fair games (sicbo, dice, gacha, slots) with bet types and endpoints. Read-only.

### `fairseal_stats` (~26 tokens)

Engine stats

FairSeal entropy engine statistics. Read-only. [requires FAIRSEAL_API_KEY]

### `fairseal_recent_games` (~27 tokens)

Recent games

List recently resolved games (useful to find game_ids to verify). Read-only.

### `fairseal_game_result` (~93 tokens)

Get game result

Fetch the result of a game by game_id (poll until resolved). Read-only.

Input parameters:

- `game_id` (string, required): Game ID — 64-char hex hash, e.g. 64096a172374489ccd4563d7c15efe5e467604dd826149da0511a0fa6109e26f (get one from fairseal_recent_games or a bet tool response)

### `fairseal_verify_game` (~45 tokens)

Verify game fairness

Verify the fairness of a completed game. Returns VDF proof data and replay steps for independent verification. Read-only.

Input parameters:

- `game_id` (string, required): Game ID to verify

### `fairseal_rng_generate` (~59 tokens)

Generate verifiable RNG

Request raw verifiable random number generation (resolves after next VDF epoch, ~5s). Returns a poll URL / game_id. [requires FAIRSEAL_API_KEY]

Input parameters:

- `client_seed` (string): Optional client-provided seed

### `fairseal_sicbo_bet` (~108 tokens)

Place Sic Bo bet

Place a three-dice Sic Bo bet. Outcomes provably fair via VDF. Resolves after next epoch (~5s); use fairseal_game_result to poll.

Input parameters:

- `amount` (number)
- `bet_type` (string, required)
- `combo` (array): Dice combination for combo bets
- `player_id` (string)
- `player_seed` (string)
- `target` (integer): Target value (total/single/double/triple bets)

### `fairseal_dice_bet` (~83 tokens)

Place Dice bet

Place a two-dice bet (exact/over7/under7/odd/even). Resolves after next epoch (~5s).

Input parameters:

- `amount` (number)
- `bet_type` (string, required)
- `player_id` (string)
- `player_seed` (string)
- `target` (integer): Target sum for exact bets

### `fairseal_gacha_pull` (~52 tokens)

Gacha pull

Pull a weighted loot box (standard or premium pool). Provably fair via VDF.

Input parameters:

- `player_id` (string)
- `player_seed` (string)
- `pool` (string)

### `fairseal_slots_spin` (~55 tokens)

Slots spin

Spin the 5-reel 3-row slot machine with wild substitution. Provably fair via VDF.

Input parameters:

- `amount` (number)
- `player_id` (string)
- `player_seed` (string)

### `fairseal_hash_content` (~80 tokens)

Hash content locally (SHA-256)

Compute the SHA-256 hex digest of a string locally. Zero network calls — the content never leaves this machine. Use it to hash an agent's input and decision text before notarizing, so only hashes (never raw content) are sent to FairSeal.

Input parameters:

- `content` (string, required): Content to hash (UTF-8). Never transmitted anywhere.

### `fairseal_notarize_decision` (~245 tokens)

Notarize an agent decision

Create a cryptographic receipt for an AI-agent decision (POST /v1/notarize, schema agent_decision). The receipt is Merkle-batched and anchored on Base mainnet; verify offline with @fairseal/verify or at the returned verify_url. Receipts prove provenance (this hash existed at this time), not correctness of the decision. [requires FAIRSEAL_API_KEY or FAIRSEAL_NOTARY_API_KEY]

Input parameters:

- `agent_id` (string, required): Stable identifier of the deciding agent
- `decided_at` (string): ISO-8601 UTC timestamp of the decision; defaults to now
- `decision_hash` (string, required): SHA-256 hex of the decision content (use fairseal_hash_content)
- `description` (string): Optional human-readable description
- `input_hash` (string, required): SHA-256 hex of the decision input (use fairseal_hash_content)
- `model` (string): Optional model identifier
- `operator` (string): Optional operator identifier
- `payload_hash` (string): SHA-256 hex of the full payload being notarized; defaults to decision_hash
- `session_id` (string): Optional session identifier

### `fairseal_notarize_status` (~78 tokens)

Get notarization receipt

Fetch a notarization receipt by receipt_id (GET /v1/notarize/{id}). Free, no key needed. Returns the receipt, Merkle proof, and on-chain anchor tx once status is 'anchored'.

Input parameters:

- `receipt_id` (string, required): Receipt ID from fairseal_notarize_decision (nr_...)

### `fairseal_anchor_submit` (~147 tokens)

Anchor a hash on Base

Queue a SHA-256 hash for Merkle-batch anchoring to Base mainnet (POST /v2/anchor, live service at x402.fairseal.io). Returns anchor_id + status_url; poll with fairseal_anchor_status until 'anchored' (typically ~60s). Auth: Bearer key (FAIRSEAL_API_KEY / FAIRSEAL_ANCHOR_API_KEY) or keyless x402 USDC micropayment (an HTTP 402 response carries machine-readable payment terms).

Input parameters:

- `metadata` (object): Optional metadata object stored with the submission
- `payload_hash` (string, required): SHA-256 hex digest of the receipt/commitment to anchor

### `fairseal_anchor_status` (~69 tokens)

Anchor status

Check anchor lifecycle by anchor_id (GET /v2/anchor/{id}, live service). Free, no key needed. Lifecycle: queued → batched → anchored (Merkle proof + Base mainnet tx hash).

Input parameters:

- `anchor_id` (string, required): Anchor ID from fairseal_anchor_submit

## Diagnostics

Captured diagnostic sections: Provenance, Dependencies. The full working is on the page: https://verifymcp.io/servers/io-fairseal-mcp-server/fairseal-mcp-server#diagnostics

## Score history

- 2026-11-05: 74
- 2026-11-04: 77
- 2026-11-03: 77
- 2026-11-02: 77
- 2026-11-01: 77
- 2026-10-31: 77
- 2026-10-30: 77
- 2026-10-29: 77
- 2026-10-28: 77
- 2026-10-27: 77
- 2026-10-26: 77
- 2026-10-25: 76
- 2026-10-24: 76
- 2026-10-23: 75
- 2026-10-22: 75
- 2026-10-21: 74
- 2026-10-20: 74
- 2026-10-19: 73
- 2026-10-18: 73
- 2026-10-17: 73
- 2026-10-16: 72
- 2026-10-15: 72
- 2026-10-14: 71
- 2026-10-13: 71
- 2026-10-12: 70
- 2026-10-11: 70
- 2026-10-07: 68
- 2026-10-04: 66
- 2026-10-03: 66
- 2026-10-02: 66

## Common questions

### What is the io.fairseal/mcp-server server?

io.fairseal/mcp-server is listed in the public MCP registry as io.fairseal/mcp-server. Verifiable entropy, provably-fair games, and receipt verification for AI agents (FairSeal API). This page covers its npm package (@fairseal/mcp-server).

### Is the io.fairseal/mcp-server server safe to use?

io.fairseal/mcp-server scores 74 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 5 November 2026. It declares no install or post-install scripts. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the io.fairseal/mcp-server server expose?

io.fairseal/mcp-server exposes 16 tools: fairseal_entropy, fairseal_games_catalog, fairseal_stats, fairseal_recent_games, fairseal_game_result, and 11 more. Their descriptions and schemas cost roughly 1,243 tokens of context every time the server is loaded.

### Is the io.fairseal/mcp-server server still maintained?

io.fairseal/mcp-server is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What licence is the io.fairseal/mcp-server server under?

io.fairseal/mcp-server declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

## Links

- npm package: https://www.npmjs.com/package/@fairseal/mcp-server
- Socket report: https://socket.dev/npm/package/@fairseal/mcp-server
- Website: https://fairseal.io/
- Changelog RSS feed: https://verifymcp.io/servers/io-fairseal-mcp-server/fairseal-mcp-server.xml
- Changelog JSON feed: https://verifymcp.io/servers/io-fairseal-mcp-server/fairseal-mcp-server.json
- HTML version of this page: https://verifymcp.io/servers/io-fairseal-mcp-server/fairseal-mcp-server