AI Summaries

Most visual diff tools give you a red-pixel overlay and leave you to figure out what changed. RegressionBot groups changed pixels into labeled regions (A, B, C…) on the 3-panel visual diff image (Before, After, and Diff with letter labels) and produces one plain-English sentence per region — so you can read a six-line summary instead of hunting through screenshots.

How it Works

After capturing screenshots, RegressionBot runs three steps to produce a summary.

Example Summary

The regressionbotSummary field is a structured JSON array — one element per labeled region, each with a label (the region letter) and a text sentence. This is the actual output for the six-region job shown above.

In most cases, reading the summary is enough to approve or escalate a job. The 3-panel visual diff image is available if you need visual confirmation.

Reflow Intelligence

Reflow is what happens when inserting or removing content shifts downstream elements — a new block added mid-page pushes everything below it downward. Pixel-diff tools can't distinguish this shift from a real change.

To handle complex layouts, RegressionBot employs layout-aware column-segmented reflow. It detects multi-column pages (such as sidebars next to main content) and aligns rows independently for each column segment. This ensures that content added or removed inside one column does not falsely offset or invalidate visual alignment in neighboring columns.

Layout Shift & Translation Check

In addition to reflow detection, RegressionBot automatically identifies harmless visual translations (such as floating header scroll misalignments or slight rendering offsets).

• How it works: For each changed region, the comparison engine checks if translating the baseline pixels by a tiny amount (up to 3 pixels) resolves the differences. If a shift is detected, it is classified directly (e.g. "Section shifted by 1px - Potential Sticky Banner").
• Performance Optimization: If all visual differences on a page are spatial layout shifts, RegressionBot records them directly and bypasses the AI-powered summary generation. This reduces processing latency.
• Mutations are preserved: If the content or styling inside a shifted region changes, the translation check fails, and the region is processed through the visual summary engine to ensure nothing is missed.

Automated AI Verdicts

Visual regressions aren't always bugs; they are often the exact intended outcome of a code change. By passing developer intent via runContext (such as the PR title and description) when starting a job, RegressionBot will automatically assess whether the detected changes match the expected intent.

For automation scripts and CI workflows, check intentAssessment.allAccountedFor or use the get_verdict MCP tool to securely pass CI without human intervention.

Using Summaries

The regressionbotSummary field is available wherever job results are returned.

import { RegressionBot } from '@regressionbot/sdk';

const client = new RegressionBot(); // reads REGRESSIONBOT_API_KEY from env
const job = await client.runProject('my-project');

await job.waitForCompletion(5000, undefined, { waitForSummaries: true }); // waits for both job and AI summary
const summary = await job.getSummary();
for (const r of summary.regressions) {
  // Typecast during transition period to avoid compilation errors on legacy SDK type declarations
  const aiSummary = (r.regressionbotSummary as unknown) as Array<{ label: string; text: string }> | undefined;
  for (const item of aiSummary ?? []) {
    // item.label = "A" | "B" | "" (empty for wholesale changes)
    // item.text  = single-sentence description
    console.log(item.label ? `${item.label}: ${item.text}` : item.text);
  }
}

Short Screenshot URLs

To make reviewing visual summaries as frictionless as possible, RegressionBot returns shortened, clickable redirect links for all screenshot fields (such as baselineUrl, currentUrl, and diffUrl).

Instead of cluttering your terminal logs or CI pipeline stdout with 600-character pre-signed URLs, you receive clean, 50-character clickable links:

Links are valid for 1 hour after generation — long enough to paste into a PR comment, Slack message, or CI log and open later. Clicking the link generates a fresh pre-signed image URL on the fly, so there is no separate expiry to track.