chaingpt-agent-wallet

name

chaingpt-agent-wallet

description

Give the AI agent its own EVM wallet with admin-controlled policies the agent CANNOT bypass even under prompt injection. Encrypted keystore (AES-256-GCM, scrypt KDF), policy file the agent has no tool to write, deterministic policy gate on every signing operation, optional local HTTP dashboard. Triggers: agent wallet, give the agent a wallet, agent address, fund the agent, agent autonomy, policy gate, kill switch, agent permissions, bounded autonomy, ERC-4337 alternative, session-key alternative.

ChainGPT Agent Wallet Skill

The agent has its own EOA wallet on every EVM chain it supports. The admin (you, in your shell) sets policies that the agent cannot violate or revoke — even if a malicious prompt convinces the LLM to try.

Threat model

The attacker's goal: prompt-inject the agent to drain its wallet to an attacker address.

The plugin's defense: the policy check is in code, not in the LLM's prompt. Every chaingpt_agent_wallet_sign_and_send call:

1. Loads the policy file fresh from disk (no caching — admin can update mid-session).
2. Runs checkPolicy(intent) — pure deterministic code that doesn't see the LLM's context.
3. Refuses if any rule fails, with a clear reason the agent surfaces back to the user.

The attacker can convince the LLM to call sign_and_send(to=attacker, value=ALL) — but the tool layer refuses because attacker isn't in allowedToAddresses or value exceeds maxTxValueWei or killSwitch=true. The trust boundary is the tool code, not the LLM.

There is no MCP tool that writes the policy file. The admin edits it directly with a text editor. There is no MCP tool that reads or sets the passphrase. The passphrase lives only in the shell env var.

Setup (admin steps — done once)

# 1. Set a strong passphrase BEFORE starting the MCP server (>= 16 chars)
export CHAINGPT_AGENT_WALLET_PASSPHRASE="your-strong-passphrase-here-min-16-chars"

# 2. Start Claude Code / the MCP server in this shell
claude

# 3. Inside Claude, initialize the wallet (one-shot)
> Use chaingpt_agent_wallet_init to set up the agent's wallet

This creates two files:

File	Contents	Who edits it
~/.chaingpt-mcp/agent-wallet/keystore.json	AES-256-GCM encrypted private key	Generated once by the init tool. Never edit by hand. Back it up.
~/.chaingpt-mcp/agent-wallet/policy.json	Plain JSON rules	You, the admin, with a text editor. The agent has NO tool that writes this file.

Both default to ~/.chaingpt-mcp/agent-wallet/ but can be overridden via CHAINGPT_KEYSTORE_FILE and CHAINGPT_AGENT_POLICY_FILE.

Tools

Tool	Mutates state?	Notes
chaingpt_agent_wallet_init	Creates keystore	One-shot. Refuses if file exists.
chaingpt_agent_wallet_address	No	Returns the agent's EOA address. Use this to receive funds.
chaingpt_agent_wallet_status	No	Address + policy digest + kill-switch state. Run this before any signing.
chaingpt_agent_wallet_balances	No	Native-coin balances across requested chains.
chaingpt_agent_wallet_policy	No (read-only)	Shows the current policy JSON. Cannot modify it.
chaingpt_agent_wallet_sign_and_send	Signs + broadcasts a tx	The only tool that can move funds. Gated by policy.
chaingpt_agent_wallet_serve_ui	Starts a local HTTP server	Dashboard on http://127.0.0.1:8787. Read-only view.

Policy file format

Default policy.json (lazily created on first read) has killSwitch: true — the agent refuses everything until the admin opts in.

Example production policy (allow DEX rebalancing on Base, capped at 0.1 ETH/tx, audit memo required):

{
  "version": 1,
  "killSwitch": false,
  "allowedChains": [8453],
  "allowedToAddresses": [
    "0x6352a56caadc4f1e25cd6c75970fa768a3304e64",
    "0x111111125421ca6dc452d289314280a0f8842a65"
  ],
  "blockedToAddresses": [
    "0x0000000000000000000000000000000000000000"
  ],
  "maxTxValueWei": "100000000000000000",
  "maxTxGas": "500000",
  "blockedSelectors": [],
  "requireMemo": true,
  "notes": "Base only, OpenOcean + 1inch routers only, 0.1 ETH cap, memo required for audit",
  "updatedAt": "2026-05-18T20:00:00Z"

Field reference

Field	Type	Behavior when unset	Behavior when set
killSwitch	bool	refuses everything (fail-closed)	true refuses everything; false proceeds to other checks
allowedChains	int[]	any chain allowed	refuses if chainId not in list
allowedToAddresses	string[]	any address allowed	refuses if to not in list (case-insensitive)
blockedToAddresses	string[]	nothing blocked	refuses if to matches (case-insensitive)
maxTxValueWei	string	no cap	refuses if native value > max
maxTxGas	string	no cap	refuses if gasLimit > max
blockedSelectors	string[]	nothing blocked	refuses if first 4 bytes of data match (e.g. 0xa9059cbb blocks ERC-20 transfer)
requireMemo	bool	no memo required	refuses if the memo arg is missing

Precedence: kill switch > blockedToAddresses > allowedToAddresses > value caps > gas cap > blockedSelectors > memo. Any single failure refuses the tx.

Pre-flight checklist

1. chaingpt_agent_wallet_status   # see address + policy digest + kill switch state
2. chaingpt_agent_wallet_balances # confirm funded on the target chain
3. chaingpt_agent_wallet_policy   # read the active rules in full
4. chaingpt_agent_wallet_sign_and_send chain=… to=… valueWei=… data=… memo="…"

If the call gets refused with a policy reason: do not try to work around it from the agent side. Surface the reason to the admin and let them edit the policy file (or override) themselves.

Local admin dashboard

> Use chaingpt_agent_wallet_serve_ui

Returns a http://127.0.0.1:8787 URL and a one-time admin token printed in the tool output (also saved to ~/.chaingpt-mcp/agent-wallet/.admin-token, 0600). The token rotates on every restart.

Open the URL in your browser. Paste the admin token at the login screen. The dashboard then shows:

• Deposit address with QR code
• Multi-chain native-coin balances (refresh page to update)
• One-click kill switch — engage or disable, single button
• Policy JSON editor — full inline editor, validated server-side, atomic write with .bak backup
• Keystore + policy file paths for reference

Why this is safe even though the dashboard CAN edit the policy

Recall the threat model: the attacker controls the LLM via prompt injection. The defenses, in layers:

1. No MCP tool exposes a write to the policy file. The LLM literally cannot reach the savePolicy function — it's only imported by the localhost HTTP server.
2. The localhost HTTP server has no client inside the agent. The plugin has no MCP tool that does arbitrary HTTP POSTs to localhost. The LLM cannot trigger the dashboard's POST endpoints even by trying.
3. Admin auth required. Even if a future tool somehow gained HTTP access, every POST endpoint requires a valid session cookie that's only set after the admin pastes the token. The token rotates every restart and lives only in admin-controlled state (env / file with 0600 perms).
4. Origin + Referer check. Cross-origin POSTs (CSRF) are rejected. Browsers always set Origin on form submits.
5. Strict schema validation. Even with a valid session, the policy editor rejects unknown fields, bad chain IDs, malformed addresses, non-integer wei values, etc. Garbage cannot make it onto disk.
6. Atomic write + .bak. A botched save can't corrupt the policy file mid-write, and the previous version is recoverable.
7. Bound to 127.0.0.1 only. Never on 0.0.0.0 — the dashboard is not reachable from other machines on the network.

The single failure mode that would bypass all of this: malware running on the admin's machine that can read the admin token file AND make HTTP requests to localhost. At that point the attacker has shell access and can read the keystore directly; the policy file is no longer the weakest link.

Dashboard endpoints

Method	Path	Behavior
GET /	login form (if unauthed) or redirect to /dashboard	—
POST /login	check admin token, set session cookie, redirect to /dashboard	requires Origin
GET /dashboard	full admin UI (auth required)	—
GET /api/policy	current policy JSON	requires session
POST /api/policy	save new policy after validation	requires session + Origin
POST /api/killswitch	toggle the kill switch (set=on/off)	requires session + Origin
GET /api/status	JSON with address + balances + policy digest	requires session
GET /logout	clear session cookie, redirect to login	—

What this skill does NOT do

• Solana / non-EVM signing. The agent wallet is EVM-only. Solana program-instruction signing is a separate path not yet wired.
• Multi-sig. This is a single EOA. For larger sums use a Safe / Gnosis multi-sig and have the agent's EOA be one signer; the policy still applies to the agent's signing.
• Session keys / ERC-4337. Bounded smart-account autonomy is a different model (smart account holds funds, agent gets a revocable session key). This skill is the simpler EOA + policy-file approach; ERC-4337 is a future feature.
• Recover lost passphrases. Lose CHAINGPT_AGENT_WALLET_PASSPHRASE → the keystore is unrecoverable. There is no recovery path. Back up the passphrase out-of-band (1Password, hardware safe, etc.).
• Read or change the policy from the agent's tools. Deliberately. Edit the file with your text editor.

Funding the agent

1. Get the address: chaingpt_agent_wallet_address
2. Send funds from any wallet (CEX withdrawal, MetaMask, hardware wallet, etc.) to that address on any chain the policy allows.
3. Confirm: chaingpt_agent_wallet_balances chains=[base,arbitrum]

The agent is now ready to operate within its policy bounds.

Credit accounting

All agent-wallet tools cost 0 ChainGPT credits. The wallet is custody-on-the-user's-machine (not custody-via-ChainGPT). The credit funnel comes from upstream tools the user/agent calls (chaingpt_research_token, chaingpt_risk_token, chaingpt_intel_token) before deciding to deploy.

Reference

• Keystore format: AES-256-GCM with scrypt (N=2^14) KDF. File version 1.
• Default paths: ~/.chaingpt-mcp/agent-wallet/{keystore.json,policy.json} (override via env).
• File perms: 0600 for keystore, 0700 for parent dir (POSIX).