Shadow — Private ETH Transfer on Taiko

Shadow is a privacy-preserving ETH claim system on Taiko L2. An agent deposits ETH to a deterministically-derived "target address" on L1 Ethereum, then claims on Taiko L2 using a ZK proof — without linking depositor and recipient.

Network Selection: If the user has not specified "hoodi" or "mainnet", always ask which network to use before proceeding.

No pool required. Unlike mixers, Shadow uses ZK proofs per deposit — a single user can privately transfer ETH without waiting for others to participate.

Lifecycle

Create deposit → Fund target address (L1) → Generate ZK proof → Claim on L2

Constraints: 1–5 notes per deposit, total ≤ 8 ETH, 0.1% protocol fee per claim.

Quick Decision

Situation	Use
Default / automated pipeline	Server (REST API)
No Docker server available	CLI (shadowcli.mjs)
Scripted proving only	start.sh --prove FILE (see server reference)

References

• Server & REST API — start.sh flags, 4-stage workflow, full API table
• CLI — shadowcli.mjs subcommands, mine-deposit flags
• Deposit Schema — v2 JSON schema, derivation formulas
• Contracts — deployed addresses, circuit ID, cast queries

Common Errors

Error	Fix
insufficient balance: X < Y	Fund target on L1, wait for checkpoint, retry
nullifier already consumed	Note already claimed — skip, check others
Please install docker first	Start Docker daemon
RPC chainId mismatch	Use L1 RPC matching deposit's chainId
DEPOSIT schema validation failed	See deposit schema
Server not responding	Re-run start.sh

MCP Tools for Lifecycle Verification

Step	Tool	Purpose
Before deposit	get_balance	Verify source address has enough ETH on L1
After funding	get_transaction_info	Confirm L1 funding tx is confirmed
During prove	get_bridge_message_status	Track cross-chain relay status
Before new deposit	get_pending_messages	Check for stuck prior deposits
Before claim	get_gas_price	Estimate L2 claim tx cost

CLI Quick Reference

taiko bridge status <TX_HASH> --json    # check bridge relay for L1 funding tx
taiko bridge history <ADDRESS> --json   # list all bridge deposits for an address

Deposit Lifecycle Tracking

Use TaskCreate / TaskUpdate to persist deposit_id across session interruptions:

• Create task at deposit creation, include deposit_id and targetAddress in description
• Update task after each step (fund, prove, claim)
• On resume: TaskList → find in_progress shadow deposits → extract deposit_id

Related Skills

• Network RPC endpoints: taiko/references/networks.md
• Bridge relay context: taiko/references/bridge-interface.md

Security

• Deposit file = secret — never commit or log it; loss = unrecoverable ETH
• The target address has no known private key; ETH can only leave via claim
• Shadow provides privacy but does not guarantee full anonymity