Dungeon Snap

A MetaMask Snap that turns your MetaMask into a full wallet for the dungeon-1 Cosmos chain. Derive a dungeon1... address from your existing MetaMask seed, view your $DGN balance, sign messages, and send DGN — all without leaving MetaMask.

Built for the Dungeon platform — DEX, NFT Marketplace, Kosmic Quest, and Cosmos validator services.

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What works today

Slice-by-slice build status. Each slice shipped with green tests.

RPC method	Status	Description
dungeon_getAccount	shipped	Returns { address, pubkey } derived via SLIP-44 coin type 118.
dungeon_getBalance	shipped	Queries live DGN balance from api.dungeongames.io.
dungeon_showAccount	shipped	Displays an info dialog with address + balance.
dungeon_signArbitrary	shipped	Raw SHA256 message signing. Returns 64-byte compact secp256k1 signature.
dungeon_signADR036	shipped	Keplr-compatible ADR-036 message signing. Same shape, signs over the canonical sign doc.
dungeon_buildSendTx	shipped	Builds + signs a MsgSend tx without broadcasting. Returns { txBytes, accountNumber, sequence, signature }.
dungeon_sendTokens	shipped	Signs and broadcasts a MsgSend tx via the LCD. Returns { txhash, code, rawLog }.
dungeon_swapAndBridgeToCard	not implemented	Skip Router cross-chain "Spend my DGN" flow. Blocked on Skip chain-registry PR.

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Quick start (developer)

# install deps + initial build
yarn install
yarn workspace dungeon-snap build

# run the test suite (rebuilds bundle then runs jest)
yarn workspace dungeon-snap test

# start local Snap server on http://localhost:8080
yarn workspace dungeon-snap serve

# in another shell, run the companion site
yarn workspace site start

Open MetaMask Flask, point your browser at http://localhost:8000, and click Connect to install the local Snap.

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Calling the Snap from your dapp

// Install the snap (user prompts once)
await window.ethereum.request({
  method: 'wallet_requestSnaps',
  params: { 'npm:dungeon-snap': {} },
});

// Get the user's dungeon-1 address
const { address, pubkey } = await window.ethereum.request({
  method: 'wallet_invokeSnap',
  params: {
    snapId: 'npm:dungeon-snap',
    request: { method: 'dungeon_getAccount' },
  },
});

// Send 1 DGN
const { txhash } = await window.ethereum.request({
  method: 'wallet_invokeSnap',
  params: {
    snapId: 'npm:dungeon-snap',
    request: {
      method: 'dungeon_sendTokens',
      params: { recipient: 'dungeon1...', amount: '1000000', memo: 'hi' },
    },
  },
});

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Architecture

• packages/snap — the Snap itself. Bundles to dist/bundle.js (~290KB).
• packages/site — companion Gatsby site for manual smoke-testing.
• Key derivation: @metamask/key-tree over snap_getBip32Entropy (path m/44'/118'/0'/0/0).
• Crypto: @noble/hashes (SHA256, RIPEMD160) + @noble/secp256k1 (ECDSA sign).
• Bech32: @cosmjs/encoding for dungeon prefix encoding.
• Protobuf: cosmjs-types for MsgSend, TxBody, AuthInfo, SignDoc, TxRaw.
• Why NOT @cosmjs/crypto: its transitive dep @noble/curves ships a method named .eval, which MetaMask's SES sandbox rejects via regex. Use @metamask/key-tree + @noble/hashes + @noble/secp256k1 instead.

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Slice 3 (Skip Router) is blocked

The flagship "Spend my DGN" flow swaps DGN → USDC on the Dungeon DEX, bridges to Linea via Axelar GMP, and leaves the funds spendable with MetaMask Card. This requires Skip Router to support dungeon-1.

Unblock path:

1. Submit a chain-registry PR to skip-mev/networks for dungeon-1 with its IBC channels to Axelar.
2. Wait for Skip to deploy support for dungeon-1.
3. Wire up @skip-go/client in this Snap. The dungeon_swapAndBridgeToCard method already exists with a clear error pointing here.

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Chain config (verified 2026-05-25)

• Chain ID: dungeon-1
• SLIP-44 coin type: 118 (standard Cosmos)
• Bech32 prefix: dungeon
• Native denom: udgn (1 DGN = 1,000,000 udgn)
• LCD endpoint: https://api.dungeongames.io
• Min gas price: 0.05 udgn/gas
• Snap defaults: gas 200,000 + fee 14,000 udgn (0.014 DGN) per send

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Test coverage

13 tests, all green via yarn workspace dungeon-snap test:

• Derives a valid dungeon1 bech32 address
• Derivation is deterministic
• Balance fetches from live LCD
• ADR-036 + raw-sha256 signing produce 64-byte low-S signatures
• Signing is deterministic (RFC6979)
• User-reject paths throw clean errors
• Send rejects invalid bech32, zero amounts, and user-cancels
• Send surfaces "account does not exist" cleanly for unfunded test wallets

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AI play-agent

tools/play-snap-agent.cjs is an automated smoke runner. It launches Chrome with MetaMask Flask loaded, drives the companion site through every smoke action, auto-clicks Flask approval popups, screenshots each step, and (with --review) sends the screenshot reel to Claude Sonnet for visual bug-flagging.

One-time setup

1. Download MetaMask Flask Chrome zip from the GitHub releases — look for metamask-flask-chrome-<version>-flask.0.zip.
2. Extract to .flask-extension/ at the repo root (so manifest.json is at .flask-extension/manifest.json).
3. Start the snap server in one terminal: yarn workspace dungeon-snap serve.
4. Start the companion site in another: yarn workspace site start.
5. Run the agent: node tools/play-snap-agent.cjs.
6. On the first run, you'll need to onboard Flask (set password, import/create a test seed). The profile is saved to ~/.dungeon-snap-flask-profile/ and reused on subsequent runs.

Modes

node tools/play-snap-agent.cjs            # headed, no AI review
node tools/play-snap-agent.cjs --review   # adds Claude Sonnet vision pass
node tools/play-snap-agent.cjs --headless # CI mode

Outputs land in ai-reports/play-session/<timestamp>/: screenshots + session.log + vision-review.md (if --review).

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License

MIT — see LICENSE.