DiffNotes

TL;DR

• Your agent (Claude Code, Codex, Cursor…) annotates a PR: a plain-language “why” for each changed block, plus screenshots, short screen recordings, Markdown reports, CSVs and small interactive HTML demos. Through the skill or the MCP endpoint.
• The notes go to your own DiffNotes server, never to GitHub, GitLab or Bitbucket: no bot comments, no notification noise.
• Reviewers with the browser extension (Chrome, Firefox) see them inside the diff on GitHub, GitLab or Bitbucket: a summary box on top, notes on the changed lines, image galleries, file previews, what changed since their last visit, one switch to hide everything.
• Notes expire on their own (after a year by default). Files on disk or in any S3-compatible bucket (Backblaze B2, R2, S3, MinIO).
• Up and running in about 5 minutes: one container, one curl | sh, one extension.

Why

Review faster	Reviewers read why a block changed before reading how. Fewer “what does this do?” round trips.
Context from the author	The agent that wrote the code explains it while it still knows the decisions and trade-offs.
Screenshots in the diff	UI changes come with before/after or mobile/desktop shots next to the lines that caused them.
Zero noise	Nothing is posted to the PR. The conversation stays for humans.
Your data	Self-hosted, invite-only (or sign-up with GitHub), per-account access. Code context never leaves your infrastructure.
Any agent, any team	One skill for every Agent Skills tool; one extension for several servers (teams, clients).

See it

On GitHub
	Summary box above the files: the PR's summary, linked reports, a notes on/off switch, expand/collapse all.
	Gallery: several images in one note (mobile + desktop), ← → to flip, Esc to close.
	Previews of attached .md, .csv and .txt files, rendered in place.
	Live demos: a small .html file runs in a locked sandbox under its note (no network, no access to GitHub); expand it at phone, tablet or desktop width.
	Floating dock once you scroll: note count, notes switch, summary popover. Long notes get show more / less.

In the app
	Every annotated PR, with its notes and attachments.
	Accounts with roles (owner, admin, member), invitations, repositories, storage per repository.
	Super admin: users, accounts, uploads, disk, and where files are stored.

Install in 5 minutes

# 1. the server (any Docker host: a VPS, Coolify, Dokku…)
git clone https://github.com/igorkasyanchuk/diffnotes && cd diffnotes
docker build -t diffnotes . && docker run -d -p 3000:3000 -v diffnotes:/data \
  -e [email protected] -e PUBLIC_URL=https://reviews.example.com diffnotes
docker logs <container> | grep "first admin"        # the generated password
#    or: docker compose up -d (docker-compose.yml), or Render / Fly.io / Railway / Coolify: docs/deploy.md

# 2. the skill, on every developer machine (Claude Code, Codex, Cursor, other Agent Skills tools)
curl -fsSL https://reviews.example.com/install.sh | sh
export DIFFNOTES_URL=https://reviews.example.com DIFFNOTES_TOKEN=dn_…   # token from /settings

# 3. the extension: https://chromewebstore.google.com/detail/fmnbgmeahjhfakpcmhimjjjplimdiibd
#    (or chrome://extensions → Developer mode → Load unpacked → extension/)
#    then its popup: server + token → Connect

Then ask your agent: “annotate this PR with diffnotes” and open the PR's Files changed tab. No skills in your agent? Use the MCP endpoint instead: claude mcp add --transport http diffnotes https://reviews.example.com/mcp --header "Authorization: Bearer $DIFFNOTES_TOKEN" (more).

Docs

Install & configure	Docker, environment variables, first admin, password reset, upgrades, backups
Deploy	Docker Compose, Coolify, Render (one-click), Fly.io, Railway; one instance only
Agent skill	Install, token, how the agent writes notes, payload format, allowed files
Browser extension	Install (Chrome, Firefox, Safari), several servers, GitHub / GitLab / Bitbucket, what you see, troubleshooting
Accounts & roles	Owner / admin / member, invitations, repository rules, super admin, overview pages
File storage	Disk or S3-compatible (Backblaze B2, Cloudflare R2, AWS S3, MinIO), expiry
Security	Access model, upload checks, sandboxing, tokens, secrets; report a vulnerability: SECURITY.md
API	The HTTP API the skill and the extension use
Development	Stack, layout, commands, code rules
Changelog

License

MIT: use it, change it, host it, sell it; keep the copyright notice.