Pair review with an agent, one diff block at a time — and the browser follows along
Diffwalk's own agent skill is a one-shot author: the agent reads the whole change, writes an ordered explanation for every block, and hands you a finished walkthrough. That's great for documenting your own PR, but when you're reviewing a colleague's PR it anchors you to the agent's verdict before you've formed your own.
pair-review turns the same CLI into a dialogue. The agent slices the diff into review units (a signature change travels with its call sites), opens the diff in the browser, then takes one unit per round: says what it does, raises its own suspicions, and stops for your take. The agreed text — not the debate — goes into the walk's explanations.yaml, so an interrupted review resumes at the next pending unit instead of starting over. A GitHub comment is only posted after you confirm its exact draft.
The newest bit: when the agent talks about a unit, the browser scrolls there and highlights the exact lines. It works through the Chrome DevTools Protocol. split-view launches a dedicated Chrome/Edge (separate profile, CDP port 9333) in the top half of the screen with the terminal below. Then each round the agent runs something like:
node scripts/focus.mjs change-003 --at src/Orders/OrderService.cs:42-50 --at src/Orders/OrderService.cs:40:old
focus.mjs attaches to that browser with Playwright's connectOverCDP, expands the file, and marks rows in the diff's shadow DOM. This works in split or unified layout, on the new side or (:old) the deleted side. The first range is scrolled to the centre of the screen. Your terminal keeps keyboard focus throughout, unlike the old approach of typing an anchor URL into the omnibox.
It needs a patched Diffwalk build: shukebeta/diffwalk branch local-both adds a Wrap toggle for long lines and shows each block's change-0NN id on the page, so "change-012" is something you can actually see. Build it with the bun version CI pins. A different bun silently tree-shakes the report's web components, and every diff renders unstyled:
git clone -b local-both https://github.com/shukebeta/diffwalk.git
cd diffwalk
npx --yes [email protected] install
npx --yes [email protected] run build
alias diffwalk="node $PWD/dist/diffwalk.js" # add to your shell profile
Then install the skill and its one dependency (playwright-core, no browser download — it drives the Chrome you already have):
npx skills add shuke-personal/pair-review-skill --skill pair-review -g
cd ~/.claude/skills/pair-review/scripts && npm i
Start a new agent session and say "pair review this PR". Split view plus highlighting is scripted for Windows and Linux/X11. On macOS, start the CDP browser by hand (the command is in SKILL.md §3) and focus.mjs works unchanged.