Find the root cause in failed Vercel builds.

Paste a Next.js or Vercel build log. Build Doctor redacts sensitive values, identifies the likely failure, shows the evidence trail, suggests a safe patch draft, and exports a markdown incident report.

Run Demo Diagnosis View Case Study See Architecture

Deterministic engineSecret scanLocal traceOptional DeepSeek reviewMarkdown export

Paste logsRedact secretsClassify failureShow traceDraft patchExport report

Sample input

Type error: Property 'deploymentUrl' does not exist... src/components/DeploymentCard.tsx:42:19

TYPESCRIPT_ERROR - 91% confidence

Deterministic engineLocal traceSafe patch draftOptional DeepSeek reviewMarkdown report

How it works

Build Doctor does not send raw logs directly to a model. It first redacts secrets, classifies the failure with deterministic rules, extracts evidence, maps the failure to a patch template, and prepares an exportable report.

Architecture

The local engine owns the root-cause classification, evidence extraction, trace generation, patch draft, and report export. The optional LLM layer only reviews the sanitized result and improves the explanation.

Safety model

Secrets are redacted before outputs or provider calls. Paid models are blocked by default, model output is validated, and no patch is applied automatically.

Employer proof

Why this project matters

View architecture case study

Deterministic-first AI workflow

The local engine owns classification, evidence extraction, trace generation, patch draft, and export.

Safe provider boundary

DeepSeek review is optional. Raw logs and secrets are not sent as the source of truth.

Test-covered developer tool

Build, unit, browser, and security checks verify the workflow and failure handling.

Employer-facing artifact

The app exports a markdown incident report that can be reviewed, copied, or saved.

Build Doctor Workflow

Complete the five-step review from log intake to exportable incident report.

The page sends the log to the local diagnosis API, renders a deterministic trace, presents a safe patch draft, and exports the result as markdown.

Step 1

Paste build logs

Sample build scenarios Sample logControlled sample error logs used to demonstrate the tool without exposing a real project.

Build Log Intake

Paste a failed Next.js or Vercel build log Build logThe text output from a failed deployment. It usually contains the first signal needed to identify the failure source.

Secret scan enabled

Local-first demo input only. Raw logs are redacted before classification, reporting, or optional provider review.

Step 2

Diagnose root cause

Run the local diagnosis engine to classify the failure, calculate confidence, and capture the probable root cause for review.

Step 3

Show diagnostic trace

The diagnostic trace appears after analysis and shows the deterministic engine steps plus the exact evidence lines it used.

Step 4

Suggest patch draft

The patch draft appears after diagnosis with likely file targets, a deterministic snippet, and validation commands. It is a review aid, not an automatic code change.

Step 5

Export incident report

Run a diagnosis to generate an exportable incident report.