# Diagnose a Pinterest CPA spike fast

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

The Pinterest CPA-spike sequence, attribution lag treated as a first-class suspect.

**Intent.** Why Pinterest CPA jumped: tag, lag, or auction.

## When to use

- CPA jumped beyond noise on meaningful spend.

## When not to use

- No specific contraindication beyond the preconditions below.

## Sources

Required: Pinterest Ads

## Preconditions

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

## Inputs

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

## Procedure

1. Split spend vs conversions with a lag-trimmed window. — tools: `pinterest_run_report`
2. Check conversion setup and tag recency. — tools: `pinterest_get_conversion_setup`

## Decision rules

- **When** The spike sits inside Pinterest's long attribution tail → **conclude** Probably lag, not cost: re-read in days, and say which day the verdict is due.

## 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

- Pinterest windows are long by design: judging this week's CPA this week is structurally premature.

## Output

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

## Related

- Skill: [tracking-audit](https://www.getmcpads.com/skills/tracking-audit.md)