Bug capture, in plain terms

Short definitions for the terms that come up around bug reporting, session replay and AI fixes — written to be useful whether or not you ever use Snag.

What is session replay?

Session replay is a recording of what a user actually did in your app — clicks, typing, scrolling, navigation — played back like video. Unlike a screen recording it captures the DOM, so you can inspect the real elements and styles afterwards. Replay is most useful when it's synced to the console and network activity, so the error and the action that caused it line up.

What is an AI bug-fix agent?

An AI bug-fix agent is a coding agent that reads a bug report, works through the codebase and proposes a change, usually as a pull request. What separates it from a chat assistant is that it runs autonomously against a real repository. The careful ones work in a disposable sandbox and open a PR for a human to review, rather than merging anything themselves.

What is the Model Context Protocol (MCP)?

MCP is an open standard for connecting AI agents to outside tools and data. A server exposes a set of tools, and any MCP-capable client — Claude Code, Cursor, Windsurf, VS Code, Codex — can call them. It means a system can offer context to any agent without building a bespoke integration for each one.

What is PII masking?

PII masking removes personally identifiable information — names, email addresses, card numbers, tokens — from captured data. Where it happens matters more than that it happens: masking in the browser before anything uploads means the raw values never reach a vendor's servers, while server-side masking means they arrived first and were redacted afterwards.

What is a repro test?

A repro test is an automated test that reproduces one specific bug: it fails against the broken code and passes once the bug is fixed. It's the difference between claiming a fix works and showing it — and because it stays in the suite afterwards, the same bug can't come back unnoticed.

What is a bug capture tool?

A bug capture tool lets someone report a problem in one click and collects the technical context automatically — session replay, console errors, network requests, browser and viewport details — instead of relying on the reporter to describe it. The aim is a report a developer can act on without a follow-up conversation.

See it on a real bug.

Every term above describes something Snag does in one capture: replay, console and network together, masked in the browser, routed to your tracker, with a fix PR if you want one.