Comment.io
The agent-native document editor. Humans and AI agents collaborate in the same markdown document — with real-time editing, comments, suggestions, and full authorship tracking.
Try Comment.io → · Agent start · REST reference · Optional skill
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Start with what already works
If Comment.io tools are already available, follow their own workflow immediately. For an existing comm, the standard MCP surface uses opencomm, then readcomm; use createcomm only when the human requested a new comm, never as setup verification. An account-scoped document request tool follows its own relative-path contract. For a supplied comm plus authenticated HTTPS, resolve a clean shortlink once with Accept: text/html, application/json;q=0, without Authorization or automatic redirects, and accept only an exact token-bearing Comment.io /d/{slug} Location. Then send X-Comment-Share-Ingress: 1 on the first authenticated ?docs GET at that final origin, switch to returned yourtoken, and follow that handoff. With URL fetch only (no browser UI/headers), use any supplied share URL now. Add mode=agent without removing its query and read the first response directly. For a bare slug or token-free comm URL, first try the final Comment.io origin's /d/{slug}?mode=agent; continue only when markdown is non-null. If it is null or says no readable state, ask once for Share → Copy for agent. The envelope is read-only. With interactive browser control, use the visible editor and comments UI. A hosted MCP connector takes a slug, token-free document URL, or exact clean CMNT/configured shortlink only in urlorslug; never a raw token-query URL or clean link embedded elsewhere. A local MCP tool may accept the full share URL only when its description says so. Use the startup index only when the current route does not cover the task.
Direct REST
When the user asks for a new comm and no existing tool or browser route can create it, follow the live REST setup path. It gives agents one current route through identity, anonymous fallback, per-doc tokens, creation, and revision-safe edits. Endpoint shapes and recovery behavior live in the exact REST reference. There is no SDK requirement; the protocol is plain HTTPS.
What makes it different
| | Comment.io | Google Docs | Notion | | --------------------- | -------------------------------------------------- | -------------------------- | ------------------------- | | Agent REST API | ✅ Full CRUD + comments + suggestions | ❌ Batch import/export only | ❌ No document editing API | | Agent identity | ✅ Registered handles + doc-scoped tokens | ❌ | ❌ | | Provenance | ✅ Per-edit attribution, human vs AI | ❌ | ❌ | | Multi-agent | ✅ Multiple agents, real-time, with loop prevention | ❌ | ❌ | | @mention agents | ✅ Connector inbox, local daemon, or webhooks | ❌ | ❌ | | No login required | ✅ | ❌ Google account | ❌ Account required | | Suggestion mode | ✅ API + UI | ✅ UI only | ❌ | | Real-time sync | ✅ Yjs CRDTs + WebSocket | ✅ OT | ✅ |
Integrations
- Claude Code — Plugin with Comment.io skills and local CLI notification checks
- ChatGPT / Claude chat — Hosted MCP connector with OAuth; no local install required
- OpenClaw — Channel plugin with an account-scoped commentiorequest tool after exact binding; automatic @mention delivery is separate and requires the matching installed full-handle profile plus a persistent Comment CLI/daemon on a long-lived computer (focused setup)
- Codex — Universal skill installer plus optional local MCP through the Comment.io CLI
- Any HTTP client — It's REST. If you can curl, you can collaborate.
See the integrations/ directory for setup guides.
Official channels
- CLI on npm — @comment-io/cli: npm install -g @comment-io/cli
- Agent/machine docs — comment.io/llms.txt (compact startup index) · exact REST reference
- Engineering-workflow skills — comment-hq/skills: npx skills add comment-hq/skills (skills.sh)
- Claude Code plugin — comment-hq/comment-io-claude-code-plugin
- OpenClaw plugin — comment-hq/openclaw-plugin
Local sync
CommentFS can project the configured Comment.io library scope into local Markdown files for search, context, and agent inspection. Follow the live local-sync guide; it starts by selecting the exact saved origin/account and letting the registry resolve its scoped home, then covers status, login, one-shot sync, and the optional background worker without relying on an ambient account.
Projections are read-only by default. The guide also covers the separate human browser consent that can make My Files projections writable on that computer. Shared With Me and Team Wiki projections remain read-only.