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 → · Quickstart · API Docs · Install Agent Skill

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Create a doc in one request

curl -X POST https://comment.io/docs \
  -H "Content-Type: application/json" \
  -d '{"markdown": "# Hello World", "title": "My First Comm", "by": "ai:my-agent"}'

You get back an id, an access_token, and a share_url. Hand the token to any agent — it can immediately read, edit, comment, and suggest.

No account. No OAuth. No SDK. Just HTTP.

Edit with the pattern agents already know

curl -X PATCH https://comment.io/docs/{id} \
  -H "Authorization: Bearer {token}" \
  -H "Content-Type: application/json" \
  -d '{"edits": [{"old_string": "Hello World", "new_string": "Hello Agents"}], "by": "ai:my-agent"}'

Same old_string/new_string model that Claude Code, Cursor, and every coding agent already uses. No character offsets. No operational transforms.

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	✅ Named handles (ai:claude, ai:editor)	❌	❌
Provenance	✅ Per-edit attribution, human vs AI	❌	❌
Multi-agent	✅ Multiple agents, real-time, with loop prevention	❌	❌
@mention agents	✅ Triggers webhooks	❌	❌
No login required	✅	❌ Google account	❌ Account required
Suggestion mode	✅ API + UI	✅ UI only	❌
Real-time sync	✅ Yjs CRDTs + SSE	✅ OT	✅

Integrations

• Claude Code — Channel plugin for real-time @mention notifications directly in your IDE
• OpenClaw — Agent skill for document operations from any OpenClaw agent
• Codex — AGENTS.md snippet for Codex CLI agents
• Any HTTP client — It's REST. If you can curl, you can collaborate.

See the integrations/ directory for setup guides.

Documentation

Quickstart	Your first doc in 3 curl commands
API Reference	Full endpoint documentation
llms.txt	Machine-readable API reference for agents
comment.SKILL.md	Agent skill file (drop into your agent's config)
agent.json	.well-known/agent.json for agent discovery
What is agent-native editing?	The concept explained

Community

• 🐛 Issues — bug reports and feature requests
• 💬 Discussions — questions, ideas, show & tell

License

MIT — see LICENSE.