The same agent that builds it helps you review it.

Comment on a line. It answers, and its fix lands in the diff you are still reading.

Not an AI reviewer. You read; it answers.

$npx skills add DiffoHQ/diffo --skill diffo -g

Twenty seconds of one real review: the question on the line, the answer from the session that wrote it, and the fix landing underneath. Nothing here is a mock-up.

The same agent

It wrote the code

Not a bot that read your diff afterwards. The session that made the change is still running, and it still remembers why it made it.

It helps you review

You read; it answers

Ask on any line and the answer comes back in your thread. It never grades the diff, never leaves nitpicks, never says anything is “fine”.

On the spot

It changes the code

Ask for a change and the fix lands in the diff you are already reading — before the commit, before the pull request, while it is still cheap.

The asymmetry— read the docs

We write code with an LLM.
We review it alone.

Writing became a conversation: you and the model in the same window, trading context until the thing is right.

Reviewing never did. The code lands, the conversation ends, and you go read four hundred lines by yourself — in a viewer built for a world where whoever wrote it had already moved on.

Diffo keeps the conversation open through the review. Ask what a hunk does and the agent that wrote it answers in the thread. Ask why, and it explains, with a diagram when the shape needs one. Ask for a change and it makes it, and the diff updates while you read. The judgement stays yours. You just stop reading alone.

The loop— read the docs

Four steps, and you're in it.

1
It orients you
On a multi-file or structural change, one guide comment: what the change does, plus a mermaid diagram when the shape is easier to see than to read. No verdicts. Nothing is “fine”.
2
You read
Syntax-highlighted unified or split diffs, word-level marks, keyboard-first movement, per-file viewed tracking. GitHub's conventions on purpose — you shouldn't have to learn a new diff.
3
You comment
On a line, a range, a file, or the whole changeset. Each thread is a Change or a Question, so a question never turns into an unrequested refactor.
4
It answers
Answers land inline in your threads. Fixes land in the diff you're reading — so you're reading the fix itself, not a promise of one.

What you get— read the docs

A reading tool, not a verdict machine.

A thread is a decision

Each comment is one small call: change this, explain that, leave it alone. The review is the sum of those decisions, not a grade at the end.

Live while you iterate

Fixes land in the diff you're already reading. A hunk you'd marked read says changed since you read it once it's edited, so the second pass stays honest.

One setup, every agent

Claude Code, Cursor, Codex, VS Code, Copilot CLI, Gemini CLI, Amp, Goose, OpenCode — whichever you already use.

Entirely local

One process on your machine, bound to loopback. No account, no telemetry, no cloud, zero network calls, and nothing to configure.

Where it fits— read the docs

Before the pull request, not instead of it.

A pull request is how you hand finished work to someone else. Diffo is the step before that: the loop where you and the agent turn a first draft into something worth another person's time.

Diffo compared with pull request review and AI reviewer bots
Dimension	Diffo	Pull request review	AI reviewer bot
When	before the PR exists	after you push	after you push
What it's for	getting the code right	getting it approved	catching the obvious
Who you work with	the agent that wrote it	your teammates	nobody
Where the code is	uncommitted, on your disk	pushed to a branch	pushed to a branch
What comes out	code worth pushing	an approval and a record	a list of comments

Under the hood— read the docs

Small, local, and boringly solid.

TypeScript on Node 24: a Hono server over loopback serving a React 19 UI, live updates over server-sent events from one recursive filesystem watch, and state in a single SQLite file through the runtime's built-in node:sqlite — so there is no database to install. The server rejects non-loopback Host and Origin headers, so a web page can't reach into your repo through it.

1,000: tests across 57 files
0: network calls
1: command to try it
Apache-2.0: all of it, today

Scanned by Snyk on 3 September 2026: passed, risk low. You are installing an Agent Skill, so it is a fair thing to ask about — and the source is Apache-2.0, so you can read every line of it yourself.

Stop reading alone.

Wire it to your agent

$npx skills add DiffoHQ/diffo --skill diffo -g

Then say /diffo in any session — Claude Code, Cursor, Codex and six more.

Or just read a diff

$npx -y @diffohq/diffo

Opens your uncommitted work in the browser. No agent needed.

Requires git and Node 24 or newer.

★ Star on GitHub Read the docs