Lets an agent pay for x402 APIs in USDC on Arc, under a spending policy it cannot change.
Setup
Choose your client, copy the config, then fill in any required environment variables.
claude mcp add cra-agent --env CRA_NETWORK='<CRA_NETWORK>' --env CRA_KEY_FILE='<CRA_KEY_FILE>' -- npx -y @cra-agent/mcp~/.codex/config.toml
[mcp_servers.cra-agent]
command = "npx"
args = ["-y", "@cra-agent/mcp"]
env = { CRA_NETWORK = "<CRA_NETWORK>", CRA_KEY_FILE = "<CRA_KEY_FILE>" }
# codex mcp add cra-agent --env CRA_NETWORK='<CRA_NETWORK>' --env CRA_KEY_FILE='<CRA_KEY_FILE>' -- npx -y @cra-agent/mcp~/.cursor/mcp.json
{
"mcpServers": {
"cra-agent": {
"command": "npx",
"args": [
"-y",
"@cra-agent/mcp"
],
"env": {
"CRA_NETWORK": "<CRA_NETWORK>",
"CRA_KEY_FILE": "<CRA_KEY_FILE>"
}
}
}
}.vscode/mcp.json
{
"servers": {
"cra-agent": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@cra-agent/mcp"
],
"env": {
"CRA_NETWORK": "<CRA_NETWORK>",
"CRA_KEY_FILE": "<CRA_KEY_FILE>"
}
}
}
}~/.gemini/settings.json
{
"mcpServers": {
"cra-agent": {
"command": "npx",
"args": [
"-y",
"@cra-agent/mcp"
],
"env": {
"CRA_NETWORK": "<CRA_NETWORK>",
"CRA_KEY_FILE": "<CRA_KEY_FILE>"
}
}
}
}claude_desktop_config.json
{
"mcpServers": {
"cra-agent": {
"command": "npx",
"args": [
"-y",
"@cra-agent/mcp"
],
"env": {
"CRA_NETWORK": "<CRA_NETWORK>",
"CRA_KEY_FILE": "<CRA_KEY_FILE>"
}
}
}
}.trae/mcp.json
{
"mcpServers": {
"cra-agent": {
"command": "npx",
"args": [
"-y",
"@cra-agent/mcp"
],
"env": {
"CRA_NETWORK": "<CRA_NETWORK>",
"CRA_KEY_FILE": "<CRA_KEY_FILE>"
}
}
}
}Environment variables
CRA_NETWORKCRA_KEY_FILE
Replace the placeholders with your own credentials and keep them out of version control.