# Look up GA4 dimensions and metrics for a property

> Tier: recipe. Operating recipe: real tool sequence, core rules, known traps.

The metadata read that grounds every bespoke report design.

**Intent.** What fields exist on this property, custom definitions included.

## When to use

- Designing reports.
- Resolving a field name someone used loosely.

## When not to use

- No specific contraindication beyond the preconditions below.

## Sources

Required: Google Analytics 4

## Preconditions

- The account is ticked in the dashboard, confirmed via list_accounts.

## Inputs

- `window`: Analysis window. Default: last 30 days.

## Procedure

1. Pull property metadata. — tools: `ga4_get_metadata`
2. Match the analysis vocabulary to real field names.

## Decision rules

- **When** A requested concept has no field → **conclude** Say so and propose the nearest real field: silent substitution produces confident nonsense.

## Evidence requirements

- Every figure carries its account, metric and window.
- Anything below a readable sample size is reported as unjudged, not as zero.

## Human approval boundary

- The readout changes nothing. Any change it motivates goes through Safe Writes: preview, human confirmation, then apply.

## Failure modes

- Custom dimensions are property-specific: yesterday's property is not today's schema.

## Output

- **Readout**: The figures, with windows and accounts named.
- **Flags**: What deserves a deeper skill or a human decision.