# Canary Rollback block

> Canary latency chart with a p95 limit breach and rollback marker for a rolled-back release

Canary p95 latency for a rolled-back release: the release climbs through a dashed limit over a flat baseline, under an Over limit Badge. Markers flag the 25% traffic step and the rollback. Recharts in a ReUI Frame. SLO breach and incident review.

- Type: Pro block
- Category: [Composed Chart](https://reui.io/blocks/chart/composed-chart.md)
- Page: https://reui.io/blocks/chart/composed-chart/chart-37
- MCP: `get_block("chart-37")`
- Built with: Badge, Frame
- Installs with a ReUI Pro or Ultimate license; setup: https://reui.io/docs/license-setup

## Best for

A static read of one rolled back release whose p95 crosses its limit over a flat baseline, with traffic step and rollback markers

## Agent notes

- `regressionAt` hardcodes the release p95 as a ramp from 74 ms and ignores `DEPLOYMENT`, so feed measured values into `p95Release` in `bucketAt`
- `chartMarkers` labels the last bucket Rolled back, and `end` sets where the series stops; drop that marker for a release that shipped
- Legend and tooltip dots hardcode `bg-sky-500` and `bg-slate-500`, so recolor them along with the `HEALTH_CHART_CONFIG` series colors

## When not to use

- A canary still rolling out, with error rate and latency streaming toward a Promote gate: use [Canary Analysis](https://reui.io/blocks/chart/composed-chart/chart-36.md) (`get_block("chart-36")`)
- An SLO error budget spent down day by day with a forecast of when it runs out: use [Error Budget Burn](https://reui.io/blocks/chart/bar-chart/chart-42.md) (`get_block("chart-42")`)

## Install

```bash
npx shadcn@latest add @reui/chart-37
```

## About Composed Chart blocks

### When to use

- A primary series as a filled area with a goal, baseline or forecast traced as lines on the same axis
- Release health against a baseline, with limit lines and a marker where a rollback happened

### When not to use

- One volume series alone, with no goal or baseline to compare against: use the [Area Chart blocks](https://reui.io/blocks/chart/area-chart.md)
- Two or more series drawn only as strokes across shared time buckets: use the [Line Chart blocks](https://reui.io/blocks/chart/line-chart.md)

### Agent notes

- Areas and lines share one `ComposedChart`, so a new series goes in as an `Area` or a `Line` child with its own `dataKey`

Every ReUI item has a twin like this one; the index is https://reui.io/llms.txt. Agents with the ReUI MCP (https://reui.io/docs/mcp) get the same guidance from the getters named above.