A Haystack pipeline can be perfectly wired and still unsafe. The retriever returns documents. Every component did its job. But if untrusted text moved through the pipeline as ordinary context, the trust boundary was lost. That is the problem this post is about. Not bad Python. A valid component connection only says: this value fits the next component It does not say: this value is safe to influen
The Dangerous Bugs Are the Ones That Don't Crash: Building Input Validation for My MCP Server I was building an MCP server for an event platform that automates speaker communications (confirmations, reminders, calendar invites, follow-ups). An agent created a session confirmation for "Monday March 8th." March 8th was a Sunday. I caught it. But catching it was just the beginning. The confirmation
Comparison: Haystack 2.0 vs. RAGatouille 0.3 for Building High-Accuracy RAG Pipelines for Developer Docs Retrieval-Augmented Generation (RAG) has become the standard for building LLM-powered tools that answer questions using private or domain-specific data. For developer documentation (dev docs) — which includes technical jargon, versioned APIs, code snippets, and structured reference material —