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Subtext bridges the gap between your AI coding agent and your running application. Agents can read your codebase, but they can’t see what’s happening in the browser. Subtext closes that gap by connecting Claude Code, Cursor, Codex, and other agents to real production session recordings, hosted browser devtools, and a persistent semantic map of your app’s UI.

Quick Start

Install Subtext and connect your agent in minutes using the setup wizard.

Install by Framework

Add the capture snippet to Next.js, React, Vite, Remix, or any custom setup.

Session Review

Let your agent open real sessions, inspect events, and compare UI state.

Sightmap

Map your UI to semantic names so your agent understands what it’s looking at.

Privacy

Automatic form masking plus an agent-driven PII governance workflow.

Verify (Beta)

Cloud-hosted browser, proof docs, and artifacts for the closed beta cohort.

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How Subtext works

1

Add the capture snippet

Install the lightweight Subtext capture snippet in your web app. It records full production sessions efficiently enough to capture every one. Form inputs are masked out of the box.
2

Connect your agent

Run npx @subtextdev/subtext-wizard to wire up the MCP server, skills, and slash commands automatically — or follow the manual install guide for full control.
3

Your agent reviews sessions

Your agent opens a real session, steps through events, captures UI snapshots, and compares states — no human needs to scrub the recording.
4

Ship with confidence

Use the privacy governance loop to scan sessions for PII, propose masking rules, and promote them to production — all driven by your agent.

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What Subtext provides

Session Review

Replay session recordings step-by-step. Zoom to the moments that matter, capture snapshots, and compare UI state across timestamps.

Privacy Governance

Automatic form input masking from day one. Agent-driven PII scanning with a propose → approve → promote workflow.

Sightmap

Open-source YAML config that maps CSS selectors to component names, source paths, and agent memory — giving your agent lasting context.

Skills

Slash commands like /subtext:subtext-review and /subtext:subtext-session teach your agent structured workflows for reviewing and debugging real sessions.
Subtext is a child brand of Fullstory and uses Fullstory’s session capture infrastructure. The capture snippet loads fs.js from Fullstory’s edge network.