ecosystem: add Carbon & Cashmere — 177 x402 endpoints, 7 chains, own-node moat

[Nedeljko87]

Summary

Adding Carbon & Cashmere to the x402 ecosystem as a Services/Endpoints project.

Category: Services/Endpoints

What we built

Production crypto trading intelligence API with 177 x402-paid endpoints and 104 MCP tools (7 free, 97 paid), powered by own blockchain nodes:

• Bitcoin Core (pruned): 20 whitelisted RPC methods via x402 pay-per-call
• Ethereum Nimbus: Beacon chain analytics
• Kaspa (Rusty Kaspa): Network/hashrate/DAG monitoring
• Bittensor Subtensor: Subnet activity tracking, alpha-prices, validator data

Intelligence layer: ML ensemble predictions (XGBoost + LightGBM + LSTM + ARF + Meta-learner), funding-rate analysis (70-85% backtest WR), market regime detection (HMM), mempool analytics, exchange-flow tracking, BTC derivatives suite, RWA Trust Score & Tokenized-Equity Cross-Issuer Index.

x402 Integration

• 7-chain USDC payments: Base (eip155:8453), Polygon (eip155:137), Arbitrum (eip155:42161), World Chain (eip155:480), Solana, Algorand, Stellar
• Facilitators: Coinbase CDP (Base/Solana), GoPlausible (Algorand), OpenZeppelin Relayer (Stellar) — plus 12 additional facilitators advertised
• Pricing (May 2026 repricing): $0.005 commodity → $0.25 premium signals — aligned to post-batch-settlement market floor
• Bazaar v2 codified extension: @x402/extensions/bazaar with serviceName + tags + iconUrl + output_example + output_schema enrichment
• v2 extensions enabled: payment-identifier (SIWX), eip2612-gas-sponsoring, erc20-approval-gas-sponsoring, offer-receipt (EIP-712 signed offers)
• Discovery: /.well-known/x402 (177 endpoints, paginated), curated MCP at /v1/endpoints/curated-mcp
• MCP Server: Streamable HTTP + SSE, 104 tools (@carbon-cashmere/x402-mcp on npm)

Distribution

• MCP Server: @carbon-cashmere/x402-mcp@0.2.2 on npm — listed on Anthropic Official MCP Registry, Smithery (with hosted proxy), Glama
• Foundation membership: Adopter participant
• CORS-enabled for browser-based agent buyers
• DID document: /.well-known/did.json for cross-platform identity

Links

• Website: https://www.carbon-cashmere.de
• API docs: https://api.carbon-cashmere.de/docs
• x402 manifest: https://api.carbon-cashmere.de/.well-known/x402
• MCP server: npx -y @carbon-cashmere/x402-mcp
• npm: https://www.npmjs.com/package/@carbon-cashmere/x402-mcp

[kite-builds]

49 endpoints — that's a serious x402 footprint. Filed #140 for x402-saas (hosted onboarding proxy + multi-tenant facilitator). If you ever want to test a zero-SDK proxy in front of Carbon & Cashmere's surface, free first-tenant for ecosystem builders. No pressure — happy to also just trade notes on edge-cases you've hit running a high-cardinality x402 catalog.

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 1 Sum 2

[Nedeljko87]

Updated metadata.json with current state — would appreciate another look from the maintainer team.

Changes since initial submission:

• Endpoints: 49 → 177 (settlement-driven catalog growth)
• Networks: 4 → 7 (added Polygon, Arbitrum, World Chain to existing Base/Solana/Algorand/Stellar)
• MCP distribution: published on Anthropic MCP Registry, Smithery, Glama, and npm (@carbon-cashmere/x402-mcp)
• Framework compatibility: AWS Bedrock AgentCore, Coinbase AgentKit, Anthropic Claude MCP all confirmed

Commit ba3e9551 on the add-carbon-cashmere-ecosystem branch.