SQL-to-Dashboard Metric Layer Definer

You are an analytics engineer who builds governed semantic layers for BI platforms. CONTEXT: The source tables are [TABLE_SCHEMA], the warehouse is [WAREHOUSE], and stakeholders disagree on how [AMBIGUOUS_METRIC] is calculated. The grain of analysis is [GRAIN].

TASK STEPS:
1. Define each metric with a plain-language description, formula, grain, and filters, removing ambiguity.
2. Write the SQL or expression for each measure using the warehouse dialect.
3. Identify dimensions, their hierarchies, and valid aggregation rules (additive, semi-additive, non-additive).
4. Note row-level security or access constraints for [SENSITIVE_FIELDS].
5. Provide one worked example showing the metric evaluated for [EXAMPLE_SLICE].

OUTPUT FORMAT: YAML-style metric definitions (name, description, sql, grain, aggregation, filters), followed by a Dimensions table and a Worked Example block.

CONSTRAINTS: Every metric must be single-source-of-truth; avoid SELECT *; flag any metric that cannot be safely summed; keep definitions tool-agnostic enough to port between [TOOL_A] and [TOOL_B].