Crit

Review your coding agent's plans, diffs and running apps in the browser. Click a line, leave a comment, and the agent gets it.

Adaptive UI for each type of output

To an agent, plans and code are both just text. To you, reviewing a plan and reviewing a web app are different jobs.

Crit gives each type of output its own review UI. Point at the exact thing that's wrong and leave a comment for the agent:

• crit plan.md renders a markdown file with review comments.
• crit finds your git changes and shows them as syntax-highlighted diffs.
• crit http://localhost:3000 proxies your running app and adds a review layer on top.
• crit landing.html renders a static HTML file you can click and comment on.

Everything runs locally from a single binary.

Quickstart

1. Install Crit binary

Brew:

brew install crit

Go:

go install github.com/tomasz-tomczyk/crit/cmd/crit@latest

Nix:

nix profile install github:tomasz-tomczyk/crit

Arch Linux:

yay -S crit.md-bin

AUR package, maintained outside this project. Any AUR helper works in place of yay.

Windows:

iwr https://github.com/tomasz-tomczyk/crit/releases/latest/download/crit-windows-amd64.exe -OutFile crit.exe

Note: Then move crit.exe somewhere on your PATH. ARM64 users: swap amd64 for arm64. WSL users: use the Linux binary instead.

Or download the latest release from GitHub.

2. Integrate with your agent

Claude Code:

claude plugin marketplace add tomasz-tomczyk/crit
claude plugin install crit@crit

Crit also works with Cursor, GitHub Copilot, OpenCode, OMO, omp, Codex, Gemini, Qwen, Hermes, Windsurf, Cline, Grok, Aider, and Pi — any agent that can read a file and run a command. See integrations/ for all install methods and details.

3. Tell your agent to use crit

Most integrations include a /crit slash command that automates the full review loop. The agent launches Crit, waits for your review, then acts on the feedback. Repeat until you approve.

Here's a 2-minute demo walkthrough of plan review and branch review:

Usage

The recommended way is to run the /crit command in your agent after any piece of work, whether it wrote a plan or changed code. You can also launch Crit yourself in a terminal and paste the prompt back to your agent when you finish.

crit                              # auto-detect changed files in your repo
crit plan.md                      # review a specific file
crit plan.md api-spec.md          # review multiple files
crit http://localhost:3000        # review a running dev server
crit landing.html                 # review a static HTML file

In your agent chat, run /crit with any of the arguments above. Run it bare and the agent picks what to launch from the conversation.

Story mode

For larger branch, PR, MR, or range reviews, story mode adds a chaptered overview of the diff — thematic chapters, a prologue, and a support bucket for noise — so you can understand the shape of the change before line-by-line review. It is an explainer, not a reviewer.

Recommended: invoke /crit-story (or $crit-story, /skill:crit-story, depending on your agent) after crit install <tool>. Your agent authors the story in-session via crit story --prep / --story-file. Only run it when you explicitly ask — agents will not infer it from a normal /crit review.

Alternative: crit story from the terminal uses your global agent_cmd (separate LLM spend). Generation is LLM-driven exploration — cost depends on change complexity more than raw file/diff size, and does not scale linearly. In our experience, complex PRs (~20–50 files, ~2k–5k lines) land around $1–$1.40 with Claude Opus 5. See the story mode guide for commands, custom prompts, JSON shape, and token-cost notes.

Live mode

crit live <url> (or crit <url>) proxies a running dev server through Crit's review UI. Crit's iframe loads the app on a different origin/port than your browser tab, so host-scoped session cookies are not shared automatically. If the direct URL works but Crit shows a login page or hydration mismatch, forward the upstream cookies:

# one-off
crit live http://localhost:4000/dashboard --cookie "_crit_key=..."

# repeatable (Netscape jar or raw Cookie header lines)
crit live http://localhost:4000/dashboard --cookie-file .crit/live-cookies.txt

# reuse cookies from a Chrome session with remote debugging enabled
crit live http://localhost:4000/dashboard --cdp-url http://127.0.0.1:9222

Getting cookies: log in to the app in your browser, then copy the session cookie from DevTools (Application → Cookies), export a cookie jar, or start Chrome with --remote-debugging-port=9222 and pass --cdp-url so Crit reads cookies for the target origin automatically.

Config (global or project .crit.config.json; project overrides global):

{
  "live_cookie_file": ".crit/live-cookies.txt",
  "live_cdp_url": "http://127.0.0.1:9222"
}

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