# Cache-Breaking Volatile Top

> Last Run: {timestamp} — volatile placeholder that changes on every invocation
> Session: {uuid} — another volatile field
> Now: {date}

## Recent Activity

- 2026-04-19T12:00:00Z — User A edited file X
- 2026-04-19T11:45:00Z — User B pushed commit Y
- 2026-04-19T11:30:00Z — CI run Z completed
- 2026-04-19T11:15:00Z — Review comment added
- 2026-04-19T11:00:00Z — Deployment triggered
- 2026-04-19T10:45:00Z — Log rotation ran
- 2026-04-19T10:30:00Z — Backup verified
- 2026-04-19T10:15:00Z — Cache cleared
- 2026-04-19T10:00:00Z — Session started

## Current State

The status widget above renews on every turn, pushing the stable-prefix
content further down the file. Under Opus 4.7 prompt caching, any change
within the first block invalidates the cache-prefix, forcing a full
recomputation each turn and inflating token cost per session.

## Stable Content (cache target)

Below this line is content that rarely changes — the project overview,
conventions, and shared rules. But because the volatile header sits ABOVE
this stable section, it cannot benefit from caching.

## Project Overview

A fixture designed to trip the Opus 4.7 TOK scanner's cache-breaking
detector (CA-TOK-001). The first 30 lines contain volatile-looking
patterns (timestamps, session ids, running activity logs) that would
break prompt-cache reuse on every turn.

## Commands

- `npm run build`
- `npm test`

## Conventions

- Conventional Commits
- TypeScript strict