Instructions
Shared MCP server instructions for the OpenDexter / Dexter x402 Gateway. Single source of truth consumed by both the hosted server (open.dexter.cash/mcp) and the npm-installable local server (@dexterai/opendexter).
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OpenDexter
x402 payments for AI agents β search, pay, and build with paid APIs.
Skills, rules, tools, and an MCP server for Claude Code, Cursor, and any MCP client.
Browse MarketplaceΒ Β |Β Β x402 ProtocolΒ Β |Β Β SDK Docs
Install
Claude Code
claude plugins marketplace add Dexter-DAO/opendexter-ide
claude plugins install opendexter
Cursor
npx @dexterai/opendexter install --client cursor
Or add manually to ~/.cursor/mcp.json:
{
"mcpServers": {
"opendexter": {
"command": "npx",
"args": ["-y", "@dexterai/opendexter"]
}
}
}
Any MCP Client
npx @dexterai/opendexter
Add this to your client's MCP config:
{
"mcpServers": {
"opendexter": {
"command": "npx",
"args": ["-y", "@dexterai/opendexter"]
}
}
}
What This Plugin Does
This plugin ships with a real MCP server that gives your agent live tools for searching, paying for, and calling paid APIs. On top of that, it has deep SDK knowledge so the agent can help you build x402 payments into your own projects.
After installing, your agent can immediately:
- Search the Dexter Marketplace for any paid API (image generation, DeFi, analytics, AI, games β thousands of endpoints)
- Check what an API costs before paying
- Pay and call any x402 API with automatic USDC settlement
- Help you build x402 clients, servers, React apps, Stripe integrations, and access passes
What is x402?
x402 is an open protocol for machine-to-machine payments over HTTP. When an API returns 402 Payment Required, it includes payment instructions. The client pays (USDC on Solana, Base, or other chains), and the API delivers the response. No API keys, no subscriptions, no invoices.
Dexter operates the most-used x402 facilitator at https://x402.dexter.cash, processing millions of settlements across thousands of indexed endpoints from every major x402 facilitator β Dexter, Coinbase, PayAI, and more.
Plugin Contents
MCP Server β @dexterai/opendexter
Seven tools cover everything:
| Tool | Description |
|---|---|
x402_search | Semantic capability search over thousands of paid APIs. Returns tiered results (strong + related matches) ranked by quality, usage, and reputation. |
x402_check | Preview pricing per chain without spending anything. See exactly what an API costs before committing. |
x402_fetch | Call any x402 API with automatic USDC payment. Signs, pays, retries β returns the response directly with an on-chain settlement receipt. |
x402_pay | Alias for x402_fetch. |
x402_access | Access identity-gated endpoints with wallet proof (Sign-In-With-X). |
x402_wallet | Show wallet address, USDC/SOL balances, and deposit instructions. |
x402_settings | Read or update your per-call spending limit. |
Two wallets are auto-created at ~/.dexterai-mcp/wallet.json on first run β one Solana, one EVM. Fund either address with USDC and your agent can start paying for APIs immediately.
Skills (6)
Deep knowledge the agent invokes when relevant:
| Skill | What it teaches |
|---|---|
| opendexter | How to use the x402 tools: search β check β fetch workflow, quality scores, funding flows, error recovery |
| x402-client | Build x402 clients: wrapFetch(), createX402Client(), Budget Accounts for agents, Sponsored Access, keypair wallets, access passes |
| x402-server | Add x402 paywalls: x402Middleware() with multi-chain accept, Stripe PayTo, dynamic/token pricing, access passes, sponsored access injection |
| x402-react | React hooks: useX402Payment() (payment state, balances, tx info), useAccessPass() (tier discovery, purchase, auto-fetch) |
| x402-protocol | v2 spec: core types, payment flow, 3 schemes (exact, upto, bridge), HTTP/MCP/A2A transports, all CAIP-2 networks, error codes |
| x402-debugging | Diagnose failures: 27 SDK error codes, facilitator health, fee payer safety, retry support, pre-payment callbacks |
Rules (2, always-on)
Injected into every conversation so the agent always knows the fundamentals:
- x402-protocol β CAIP-2 network identifiers, header conventions, atomic units, facilitator URL, supported chains
- x402-coding β Import from subpaths (
@dexterai/x402/client), preferwrapFetch()for agents,x402Middleware()for servers
Agent
- x402-engineer β Specialized persona that knows the full Dexter x402 stack. Validates amounts and balances before payment, never exposes private keys, reaches for
x402_searchwhenever a user mentions paid APIs.
Commands (3)
| Command | What it does |
|---|---|
| setup-opendexter | Install the OpenDexter MCP server into Cursor, Claude Code, Codex, VS Code, Windsurf, or Gemini CLI. |
| setup-x402-client | Add @dexterai/x402 to a Node.js project with wrapFetch() boilerplate and a test call. |
| setup-x402-server | Add x402Middleware() to an Express app with paywall configuration and test. |
Supported Chains
| Chain | Network ID (CAIP-2) | Gas Token |
|---|---|---|
| Solana | solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp | SOL |
| Base | eip155:8453 | ETH |
| Polygon | eip155:137 | POL |
| Arbitrum | eip155:42161 | ETH |
| Optimism | eip155:10 | ETH |
| Avalanche | eip155:43114 | AVAX |
| BSC (BNB Chain) | eip155:56 | BNB |
| SKALE Base | eip155:1187947933 | sFUEL (free) |
Links
- Dexter Marketplace β Browse thousands of paid APIs
- Dexter Facilitator β Payment infrastructure
- @dexterai/x402 SDK β Build x402 clients and servers
- @dexterai/opendexter β MCP gateway for AI agents
- x402 Protocol Spec β The open standard
- Become a Seller β List your API on the marketplace
- Telegram
License
MIT
