Softbot Studio agent tools

softbot-mcp

MCP server for Softbot Studio pay-per-call agent tools. Each call is paid with USDC on Solana mainnet through x402, straight from your own wallet. There are no accounts or API keys, and failed calls are free.

Every paid tool accepts dry_run: true, which returns the price and endpoint without paying.

Free trial

The first 3 calls of each tool are free per wallet. The server signs the x402 sign-in-with-x challenge with your key automatically (a signature only, no funds move), then pays normally once the trial is used up. Results show free_trial and trial_remaining. Set SOFTBOT_NO_TRIAL=1 to always pay.

Configuration (env vars)

• SOLANA_PRIVATE_KEY (required for paid calls) is the keypair of a wallet holding a little USDC (no SOL needed, since the facilitator pays network fees). It takes base58, or the JSON byte array from solana-keygen. Use a dedicated low-balance wallet.
• MAX_SPEND_USDC is the per-session budget. It defaults to 0.25, and calls that would exceed it are refused.
• SOFTBOT_DRY_RUN=1 puts every tool in price-only mode.
• SOLANA_RPC_URL is optional and defaults to the public mainnet RPC.

Claude Desktop

claude_desktop_config.json:

{  "mcpServers": {    "softbot": {      "command": "npx",      "args": ["-y", "softbot-mcp"],      "env": { "SOLANA_PRIVATE_KEY": "<base58 or [..] key>", "MAX_SPEND_USDC": "0.25" }    }  }}

Cursor

~/.cursor/mcp.json (or .cursor/mcp.json in a project):

{  "mcpServers": {    "softbot": {      "command": "npx",      "args": ["-y", "softbot-mcp"],      "env": { "SOLANA_PRIVATE_KEY": "<base58 or [..] key>", "MAX_SPEND_USDC": "0.25" }    }  }}

Safety

• The key is used only locally to sign x402 USDC transfers, and it is never logged or sent anywhere.
• The client refuses to pay if a server asks for more than the advertised price, or for an asset other than USDC.
• The budget resets when the server process restarts.

Develop

npm install && npm run buildnode test/smoke.mjs          # list tools + dry run eachSOLANA_PRIVATE_KEY=... node test/smoke.mjs paid   # one $0.002 check_domain call

MIT licensed.