Subtext, by Fullstory

Session replay, built for agents. Subtext is agentic session review: it captures production sessions of your app and connects them to your coding agent — Claude Code, Cursor, Codex, Devin, your own harness — so it can review what real users did, reproduce reported bugs, verify its own UI changes, and manage capture privacy rules, all without leaving the terminal.

Get started

The fastest way in is the setup wizard. Run it in your project directory:

npx @subtextdev/subtext-wizard

One command handles the whole setup: it logs you in, fetches your org's capture snippet, asks which analytics tools you use, then hands the install off to your own coding agent — which wires up the capture snippet, MCP server, skills, and commands for you. Takes a few minutes.

Requires a free Subtext account — no credit card. Subtext is a hosted service that records and stores your app's sessions. Your account is where they live, and where your agent reads them from. When the wizard opens the login page, create an account in one click with Google, then come back to finish.

EU data region? Run npx @subtextdev/subtext-wizard --region eu.

What you get

Once setup is done, your agent has these tools:

• Session review — point your agent at a recorded session and it walks through what happened: the flow the user took, console errors, network activity, and where things broke. Great for debugging user-reported issues or confirming a fix landed in the real UI.
• Privacy rules — detect PII in captured sessions and manage element-block, URL, and network capture rules directly from your agent.

Driving a live browser and capturing before/after proof of code changes live in the companion Subtext Verify plugin.

Set up manually

Prefer to wire things up yourself? The wizard just automates the steps below — you can do them by hand instead.

1. Install the plugin

Claude Code

/plugin marketplace add fullstorydev/subtext
/plugin install subtext@subtext-marketplace

Cursor — install from the Marketplace panel (or a Team Marketplace that imports this repo).

Codex — open /plugins, install subtext from the repo marketplace.

Gemini CLI

gemini extensions install https://github.com/fullstorydev/subtext

Manual / openskills

npx openskills install fullstorydev/subtext

…then add the subtext MCP server (below) to your agent's MCP configuration.

2. Connect the MCP server

The subtext server runs at https://api.fullstory.com/mcp/subtext (EU1 mirror: https://api.eu1.fullstory.com/mcp/subtext). It's HTTP only — no local process required.

3. Add the capture snippet to your app

Install the Fullstory capture snippet for your org so sessions are recorded. The wizard does this for you against your org's snippet; to do it by hand, grab your snippet from your Fullstory settings.

Notes

• All tools are read-only analysis except privacy-create / privacy-promote / privacy-delete / privacy-url-create / privacy-network-create, which modify org privacy rules.
• This plugin bundles the skills subtext-review (structured session summaries), subtext-session (the review-* tool catalog), subtext-privacy (PII detection + element-block/URL/network privacy rules), and subtext-telemetry (workflow milestone logging), plus subtext-shared and subtext-using-subtext.