HarnessFEv1.0.0

A platform team hosts several independently deployed React micro-frontends inside a shell app. When a user reports a broken checkout widget, the agent uses project.tree to identify the child project, session.list to find the offending page load, and console_tail/network_tail to correlate the failure with the exact source file line from the child build.

A team runs a Next.js App Router storefront and sees hydration mismatches only in production-like preview builds. Using the Next.js integration and buildId, the agent correlates a session's console errors to the specific build and source locations, then reproduces by driving the page with page_click and page_type.

A compliance-sensitive dashboard has customers reporting lost filter state after navigation. The agent tails navigation_tail and storage_tail to trace history.pushState calls and localStorage/cookie mutations, using initiator.stack to find the exact component that cleared state.

A collaborative document editor intermittently stops syncing. Using ws_tail, the agent inspects open/send/recv/close frames and the initiating call stack on send, then pairs with page_screenshot to verify UI state at the moment of failure.

Before migrating a legacy Webpack monolith to Vite plugins, a QA team wires harness-fe into both builds and runs scripted page interactions across tabs. They compare session summaries and console/network tails between builds to catch behavioral regressions early.

The core harness-fe packages (Vite/Webpack/Next.js plugins, MCP daemon, runtime) are free and open source to drive adoption among frontend developers. Paid tiers add team dashboards, longer session retention, SSO, private package registry, and priority support for platform teams.

A hosted service ingests harness-fe session/event data (with explicit consent) and provides cross-project analytics, regression detection, and searchable rrweb recordings. Customers pay based on monthly active sessions or data volume.

Consulting and professional services help large enterprises wire harness-fe into complex micro-frontend, SSR, and Electron setups, including custom overlay plugins and CI regression gates. This complements the free core for regulated industries needing tailored onboarding.