The Day AI Argued With MDN (And Lost)

Short summary

Claude Code confidently stated Firefox didn't support the Web Serial API, though Firefox 151 had already shipped it. The core problem: LLMs answer from outdated training data and rarely admit uncertainty. Mozilla's solution is the MDN MCP Server, which gives AI assistants direct access to current documentation, making responses verifiable rather than memory-dependent.

• •Claude Code gave a confident but incorrect answer about Firefox API support due to outdated training data
• •LLMs struggle with web platform features released after their training cutoff and rarely admit uncertainty
• •Mozilla's MDN MCP Server solves this by allowing AI assistants to query live documentation instead of relying on memory

Generated with AI, which can make mistakes.