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 or the OS keychain, never in the keystore file, never in the LLM's context.

Setup (admin steps, done once)

The keystore passphrase resolves in this priority order:

1. CHAINGPT_AGENT_WALLET_PASSPHRASE env var, explicit override. Best for CI / headless / power users who want zero process-list and zero keychain exposure.
2. OS keychain, auto-managed. On macOS (Keychain via security) or Linux (libsecret via secret-tool), if no env var is set, chaingpt_agent_wallet_init generates a strong 256-bit passphrase and stores it in the keychain. You never type or remember it; the MCP server reads it back on each load.

Option A, zero-setup (macOS / Linux with a keychain), recommended for most