When Claude or another LLM is streaming a tool call and you need to work with the JSON before it finishes, this gives you three tools that actually handle the mess. parse_partial_json closes open braces and quotes to return a usable object even from truncated input, reporting confidence and how many bytes it consumed. extract_json_from_text strips markdown fences and prose around embedded JSON. validate_json does strict RFC 8259 checking with precise error positions. Built on the streamparse library, it runs via npx in Claude Desktop, Cursor, Cline, and other MCP clients. Useful when you're building agents that need to reason about their own incomplete structured outputs mid-generation.
claude mcp add --transport stdio io.github.mukundakatta-streamparse uvx streamparse