metric-creation

## Prerequisites Before creating metrics, ensure you are on the correct workspace and branch. Use `get_session_workspace_and_branch` to check the current session context. For development work, create a branch with `create_workspace_branch` (the session switches automatically). See the `workspace-branch` skill for the full workspace/branch tool reference. --- ## Overview A Honeydew **metric** is a named, reusable aggregation anchored to an entity. Unlike a calculated attribute (which is per-row), a metric collapses multiple rows into a single value. Metrics are **context-sensitive**: they automatically respond to whatever filters and groupings the consuming BI tool or analyst applies. **Your job is to build an aggregation function that users can later group by.** If a user asks for a group by ("sum sales by category"), ignore the group. You're building the aggregation to sum sales by ANYTHING. The user will later use it in a query with their chosen dimensions. Use a metric when: - The same aggregation logic is reused across dashboards, teams, or tools - You need a governed, single source of truth for a KPI (e.g. "revenue", "active users") - The calculation involves combining other metrics (ratios, deltas) **Do not** use a metric when the value is per-row (use a calculated attribute instead). --- ## Building the SQL Expression ### Core Rules - **MUST use an aggregation function** — metrics collapse rows - **DO NOT use window functions** — only aggregations allowed ...