zcash-mcp

ZAP1 receipts for Zcash agents: verify workflows without trusting the server.

ZAP1 is an attestation and proof rail for Zcash workflows. Frontier Compute maintains the reference ZAP1 implementation.

A wrapper makes you trust the server. ZAP1 makes the server unnecessary to trust.

Core rule: observe state, bound the claim, hash evidence, issue a receipt, verify later.

MCP is the standard way for AI agents to call external tools. zcash-mcp exposes the ZAP1 attestation layer for agents that need verifiable receipts around Zcash workflows: create ZAP1 attestation leaves, query anchor state, and verify proof receipts.

This is not a full wallet MCP. Balance scanning, private key custody, seed handling, PCZT signing, shielded spend construction, and lightwalletd or Zaino wallet synchronization are complementary wallet-layer work, not this server's scope.

Why ZAP1

Wallet MCPs can move value. ZAP1 proves the workflow around the value, and the counterparty can verify the proof without trusting Frontier.

Tool servers expose what a backend says right now. ZAP1 produces a receipt that another party can verify later from the schema, proof material, and Zcash anchor.

ZAP1 is the proof rail for Zcash agent workflows:

1. attest: create a typed event leaf.
2. anchor: commit leaves into a Merkle root anchored to Zcash.
3. prove: return a receipt packet for a leaf.
4. verify: let another party check the receipt without trusting the original agent.

Agent systems need more than a payment or a transaction lookup. They need a receipt that another agent, user, auditor, or service can verify later:

• what event was asserted
• which agent or workflow asserted it
• which ZAP1 leaf records it
• which Merkle root includes it
• which Zcash transaction anchored that root
• how to verify the proof without trusting the original agent

That is the lane for this server. It gives Zcash agents a receipt layer that can sit beside any wallet, signer, custody system, lightwalletd stack, Zaino stack, or application-specific payment flow.

See ZAP1 Proof Rail for the category boundary, receipt model, integration pattern, and red-team rejects. See ZAP1 Conformance for the receipt contract agents and integrations should satisfy. See Wallet Receipt Integration for the wallet-action handoff pattern. See External Rail Receipts for generic external-action receipt requests, and Receipt Disclosure Profiles for public, counterparty, auditor, grant, compliance, and internal packet shapes.

Capability Boundary

The zcash_capability_manifest tool gives agents a machine-readable scope map:

• covered here: ZAP1 receipts, lifecycle attestations, proof verification, anchor state, memo decoding, and public chain context
• excluded here: custody, seed handling, balance scanning, PCZT signing, shielded spend construction, and wallet-server synchronization
• composition rule: use this server before or after wallet-layer actions to create, query, and verify receipts

Good fits:

• agent action receipts
• payment and invoice proof packets
• wallet action receipts
• external action receipts
• operator lifecycle events
• grant proof packets
• compliance audit packets
• policy and reputation attestations
• public anchor verification for private workflows
• cross-agent handoffs where the receiver needs proof, not custody

Poor fits:

• holding keys
• scanning wallet balances
• signing PCZTs
• broadcasting shielded spends
• replacing a wallet SDK

Customer Flow

Use zcash_receipt_template first when you are wiring ZAP1 into a product. It returns a customer-ready workflow for the receipt type you want:

• agent_action: prove an agent performed a named action with specific input and output hashes
• payment_receipt: bind invoice or payment metadata to a ZAP1 leaf and later prove inclusion under an anchored root
• operator_lifecycle: record deployment, upgrade, incident, recovery, or policy state as a verifiable lifecycle event
• policy_attestation: record an agent, service, or workflow policy decision as a verifiable event

Expected flow:

1. Call zcash_capability_manifest to confirm the attestation boundary.
2. Call zcash_receipt_template for the use case.
3. For wallet actions, call zap1_wallet_receipt_request to convert the wallet result into hash-only attest_event arguments.
4. Call attest_event to create the typed ZAP1 leaf.
5. Call get_anchor_status to check whether the leaf is anchored or waiting.
6. Call verify_proof to verify tree inclusion.
7. Call zap1_prove_receipt to fetch a handoff proof bundle.

Acceptance checks:

• the receipt has a leaf hash
• the leaf verifies under a returned Merkle root
• v2 receipts retain every sibling position and the committed leaf_count
• anchor finality comes from a separately verified root-opening artifact, not txid, height, or status metadata alone
• another verifier can repeat verification without trusting the original agent
• no private keys, seeds, PCZTs, or wallet scan state were sent to this server

Red-team rejects:

• treating a payment URI as proof of payment
• treating an unanchored leaf as final settlement evidence
• treating a quote, route, or intent hash as settlement evidence by itself
• asking this server to sign, scan balances, recover seeds, or hold keys
• mixing custody claims into ZAP1 receipt claims
• hiding the distinction between wallet action and receipt verification

ZAP1 verifies ZAP1 receipts. It does not audit or guarantee any external wallet, route, payment, bridge, exchange, or settlement system referenced by a receipt.

Tools

Install

npx @frontiercompute/zcash-mcp

Or install globally:

npm install -g @frontiercompute/zcash-mcp

Quickstart

Add this to your MCP config:

{
  "mcpServers": {
    "zcash": {
      "command": "npx",
      "args": ["@frontiercompute/zcash-mcp"]
    }
  }
}

Restart your client and ask for the current Zcash block height. Read-only tools do not need an API key.

Get a trial key for write operations:

curl -s -X POST https://api.frontiercompute.cash/trial-key

Configuration

Environment variables:

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "zcash": {
      "command": "npx",
      "args": ["@frontiercompute/zcash-mcp"],
      "env": {
        "ZEBRA_RPC_URL": "http://127.0.0.1:8232",
        "ZAP1_API_KEY": "your-key-here"
      }
    }
  }
}

Any MCP Client

The server communicates over stdio using JSON-RPC. Point your MCP client at the zcash-mcp binary.

Build From Source

git clone https://github.com/Frontier-Compute/zcash-mcp.git
cd zcash-mcp
npm ci
npm run build
node dist/index.js

Testing

Offline verification covers the built stdio server and a clean-room install from the packed npm tarball:

npm run test:offline

Live verification hits a real Zebra RPC and ZAP1 API:

ZEBRA_RPC_URL=http://127.0.0.1:8232 \
ZAP1_API_URL=http://127.0.0.1:3080 \
ZAP1_API_KEY=your-key-here \
npm run test:live

test:live drives the MCP server over stdio and exercises the live tool surface, not just the underlying HTTP endpoints. Set ZAP1_AGENT_ID if you want the get_agent_status check to target a specific deployed agent.

GitHub Actions mirrors that split:

• .github/workflows/offline-ci.yml runs deterministic packaging and MCP handshake checks on every push and pull request.
• .github/workflows/live-e2e.yml runs secret-backed live checks on main, on a schedule, and by manual dispatch.

Dependencies

• A running Zebra node for chain queries
• The ZAP1 API for attestation, proof, anchor, event, and receipt tools
• Memo decoding works locally with no external dependencies

Related Packages

Links

• Dashboard
• MCP Registry
• Frontier Compute
• Live stats

License

MIT