v5.35.0 — MCP conformance + x402 agent sandbox

What's new

MCP conformance improvements

• Fixed ping handler (was returning -32601, now returns {} per spec)
• Capabilities advertise tools, resources, and prompts
• CORS: Authorization header + GET method added to Access-Control-Allow-Headers/Methods
• Strict JSON Schema (additionalProperties: false) on all 4 tool inputSchemas
• tools/call with missing name returns -32602 (not -32601)
• get_market_schedule error handling hardened (try/catch, graceful SCHEDULE_ERROR)
• handleMcp outer catch returns -32603 Internal error (not Worker 500)
• verify_receipt description corrected (SIGNATURE_VALID, not signature_valid)

x402 agent-native sandbox

• POST /v5/sandbox with X-Payment header ($0.001 USDC on Base mainnet) returns ho_crd_ key with 10 credits
• No email required — fully autonomous agent onboarding
• Per-request x402 path also available (no key ever needed)

Test suite

• 619/619 tests passing
• All legacy key enforcement tests fixed
• 10 new MCP protocol conformance edge case tests

Infrastructure

• x402 live on Base mainnet (facilitator: CDP)
• x402 Foundation launched under Linux Foundation same day (April 2, 2026)
• Ed25519 signing, 28 global exchanges, 60-second TTL