Causal Dag Builder

Build a refinable causal DAG before answering "did X cause Y" on observational data. Emits a Mermaid diagram of assumed causes, applies the back-door criterion to decide what to condition on, and forces confounders, mediators, and colliders to be named explicitly instead of "controlling for everything". The DAG is an artifact downstream skills read to pick the right adjustment set. Use whenever interpreting cohort comparisons, funnel drop-offs, or any analytics result where the user is reasoning causally without an experiment. Pairs with analytics-diagnostic-method as the causal-structure layer underneath the diagnostic tree. Triggers when Clamp MCP cohortscompare or funnelscreate is called with no experimental holdback, when a Clamp MCP result prompts a causal claim from observational data, or when via Clamp the user asks "why did this segment convert higher".