{"slug": "every-mcp-tool-argument-is-model-chosen-so-the-signature-is-the-boundary", "title": "Every MCP tool argument is model-chosen, so the signature is the boundary", "summary": "Every argument passed to a Model Context Protocol (MCP) tool is chosen by the model, making the tool's signature the critical boundary for safety and control, according to a post promoting the 'MCP Starter Kit' on Gumroad. The article, linked from Hacker News, emphasizes that developers must design MCP tool signatures carefully because the model determines all inputs.", "body_md": "Article URL: \nhttps://fulcrumenterprises.gumroad.com/l/mcp-starter-kit\n\nComments URL: \nhttps://news.ycombinator.com/item?id=49591829\n\nPoints: 1\n\n# Comments: 0", "url": "https://wpnews.pro/news/every-mcp-tool-argument-is-model-chosen-so-the-signature-is-the-boundary", "canonical_source": "https://fulcrumenterprises.gumroad.com/l/mcp-starter-kit", "published_at": "2026-09-06 23:07:26+00:00", "updated_at": "2026-09-06 23:32:18.276419+00:00", "lang": "en", "topics": ["ai-agents", "ai-tools", "developer-tools"], "entities": ["Model Context Protocol (MCP)", "Gumroad", "Hacker News"], "alternates": {"html": "https://wpnews.pro/news/every-mcp-tool-argument-is-model-chosen-so-the-signature-is-the-boundary", "markdown": "https://wpnews.pro/news/every-mcp-tool-argument-is-model-chosen-so-the-signature-is-the-boundary.md", "text": "https://wpnews.pro/news/every-mcp-tool-argument-is-model-chosen-so-the-signature-is-the-boundary.txt", "jsonld": "https://wpnews.pro/news/every-mcp-tool-argument-is-model-chosen-so-the-signature-is-the-boundary.jsonld"}}