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177 crypto market intel endpoints with auto x402 USDC micropayments from your AI agent
177 crypto market intel endpoints with auto x402 USDC micropayments from your AI agent
This MCP server implements a legitimate cryptocurrency micropayment system for API access with reasonable security practices. The architecture properly isolates private keys to the local machine and implements payment signing correctly. However, there are concerns about private key exposure in the Claude Desktop config file, insufficient input validation on path parameters, and logging of potentially sensitive request details that warrant a moderate risk assessment. Supply chain analysis found 7 known vulnerabilities in dependencies (0 critical, 2 high severity). Package verification found 1 issue.
5 files analyzed · 15 issues found
Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.
This plugin requests these system permissions. Most are normal for its category.
Set these up before or after installing:
Environment variable: EVM_PRIVATE_KEY
Environment variable: SVM_PRIVATE_KEY
Environment variable: X402_TOOL_LIMIT
Add this to your MCP configuration file:
{
"mcpServers": {
"io-github-carboncashmere-x402-mcp": {
"env": {
"EVM_PRIVATE_KEY": "your-evm-private-key-here",
"SVM_PRIVATE_KEY": "your-svm-private-key-here",
"X402_TOOL_LIMIT": "your-x402-tool-limit-here"
},
"args": [
"-y",
"@carbon-cashmere/x402-mcp"
],
"command": "npx"
}
}
}From the project's GitHub README.
MCP server that exposes Carbon & Cashmere's 177 crypto market intelligence endpoints to your AI agent — with automatic x402 USDC micropayments from your wallet.
When this MCP is installed, your AI agent can call tools like:
get_v1_news — analyzed crypto news with sentiment + market impactget_v1_stablecoins — total market cap, per-coin supply, chain distributionget_v1_onchain_btc — Bitcoin on-chain metrics (hash-rate, mempool, miner flows)get_v1_bittensor_leaderboard — top-100 Bittensor miners by emissionget_v1_mantis_realized_accuracy — MANTIS subnet (UID 253) realized accuracy track-recordget_v1_intel_snapshot — aggregated market intel snapshot177 paid endpoints total. Default exposes top 100 (curated by revenue + popularity). Set X402_TOOL_LIMIT=177 to expose all incl. per-coin variants.
Each tool invocation triggers a single USDC micropayment from your configured wallet. No subscription. No API key. Pay only for what you use.
Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):
{
"mcpServers": {
"carbon-cashmere": {
"command": "npx",
"args": ["-y", "@carbon-cashmere/x402-mcp"],
"env": {
"EVM_PRIVATE_KEY": "0x_your_evm_private_key_here",
"SVM_PRIVATE_KEY": "your_base58_solana_private_key_here_optional"
}
}
}
}
Restart Claude Desktop. The top 100 Carbon & Cashmere tools (curated by revenue + popularity) appear in your tool palette.
Same JSON config, paste into your MCP settings panel.
Security: use a dedicated spending wallet, not your main wallet. Your
EVM_PRIVATE_KEYsits in plaintext in your Claude Desktop config. Any process on the host with read access to that file gets the key. Treat it as a hot wallet you would not mind losing: fund it with the small amount you plan to spend ($10–$50 in USDC), never with your main holdings.
0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80)Network whitelist. The MCP server only signs payments for networks that
appear in the API's 402-response accepts[] array (currently Base, Polygon,
Arbitrum, World Chain, Solana, Algorand, Stellar). Requests routed to any
other chain are rejected at the signing layer — your key cannot be tricked
into signing for an arbitrary network.
Keys never leave your machine. They live only in your Claude Desktop config and the MCP process running locally. Payment signing happens on your device; only the signed EIP-712 / SIWS payload travels to Carbon & Cashmere.
If you start the MCP server without EVM_PRIVATE_KEY and without
SVM_PRIVATE_KEY, it runs in discovery-only mode: tool registration
works, free endpoints work, paid tool invocations surface a 402 error to the
agent. Useful for: evaluating the tool catalog, MCP marketplace introspection
(Glama, npm scrapers), or running in a CI/test environment without funding
a wallet.
Claude Desktop @carbon-cashmere/x402-mcp api.carbon-cashmere.de
| (your machine) (our server)
| call get_v1_news | |
|------------------------->| GET /v1/news |
| |-------------------------------->|
| | 402 + PAYMENT-REQUIRED |
| |<--------------------------------|
| | sign with EVM_PRIVATE_KEY |
| | GET /v1/news + PAYMENT-SIG |
| |-------------------------------->|
| | 200 OK + data |
| |<--------------------------------|
| formatted data | |
|<-------------------------| |
Built on official Coinbase x402 v2 protocol. Settlement happens on Base USDC (or your chosen chain). Typical latency: ~2-3 seconds per call (one-shot payment + data).
By default, the top 100 tools are exposed — curated server-side by a scoring that combines actual settlement volume, USD revenue, exploration weighting, and description quality (the catalog re-ranks without requiring an npm re-publish).
X402_TOOL_LIMIT | What you get |
|---|---|
50 | Minimal footprint — top free + bundles + a few high-revenue endpoints |
100 (default) | High-revenue tier — adds $10–$50 subscriptions, sponsor tiers, weekly/daily reports, on-chain bundles |
177 | Everything — adds per-coin specialized routes (vol-regime/{coin}, hurst/{coin}, trend/{coin}, …). Recommended only when your agent knows which coin to query. |
Override:
"env": {
"X402_TOOL_LIMIT": "177"
}
Why a default cap: too many MCP tools can degrade an agent's tool-selection accuracy. 100 is the empirical sweet spot for Claude 3.5 Sonnet and newer.
| Variable | Required | Default | Description |
|---|---|---|---|
EVM_PRIVATE_KEY | one of | — | 0x-prefixed EVM key for Base/Polygon/Arbitrum |
SVM_PRIVATE_KEY | one of | — | base58 Solana keypair |
X402_API_BASE | no | https://api.carbon-cashmere.de | API base URL |
X402_TOOL_LIMIT | no | 100 | Max tools exposed (1-177) |
X402_LOG_LEVEL | no | info | debug | info | warn | error |
MIT — see LICENSE.
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