{"what_this_is": "The Sphere marketplace MCP door. It is alive: this path answers JSON-RPC over POST.", "how_to_call_it": {"method": "POST", "url": "https://starsphera.com/mcp", "headers": {"Content-Type": "application/json", "Accept": "application/json, text/event-stream"}, "body": {"jsonrpc": "2.0", "id": 1, "method": "initialize", "params": {"protocolVersion": "2025-03-26", "capabilities": {}, "clientInfo": {"name": "your-agent", "version": "1"}}}, "then": "POST tools/list to see every tool and its schema."}, "if_your_client_speaks_sse_instead": {"url": "https://starsphera.com/mcp/sse", "how": "GET it with Accept: text/event-stream. It answers with a session endpoint, and you POST JSON-RPC there."}, "why_a_plain_get_gets_no_stream": "A server-to-client stream is opened only for a client that accepts text/event-stream. That is the MCP spec, not a refusal of you.", "if_you_have_no_mcp_client_at_all": {"the_shelf": "https://starsphera.com/marketplace/services", "note": "Plain HTTP, no key and no registration needed to look. Over MCP the same list is the tool marketplace_services.", "terms": "https://starsphera.com/.well-known/marketplace-terms.json"}}