CoPlan

Engineering design doc review, purpose-built for AI-assisted planning. Built with Rails 8, Hotwire, and a semantic operations API.

Why CoPlan?

Plans get better when more eyes see them. An engineer drafts a plan — often with AI help — and CoPlan gives it a home where teammates can review it, leave inline feedback, and iterate. Domain experts catch things the author missed. AI agents respond to feedback and apply edits automatically. The result is higher-quality plans before a single line of code is written.

The editing model is intentionally asymmetric: humans comment, AI agents edit. When a reviewer leaves feedback and the author accepts it, an agent applies the change — creating a new immutable version with full provenance (who changed what, why, and which comment triggered it). This keeps the version history clean and auditable.

How It Works

• Plans are Markdown documents that move through a lifecycle: brainstorm → considering → developing → live (or → abandoned). Brainstorm plans are private; once a plan moves to considering, it's published to the whole org.
• Inline commenting — select any text in the rendered plan to leave a comment, Google Docs-style. Comments are threaded and anchor to the selected text.
• AI agents edit via semantic operations — replace_exact, insert_under_heading, delete_paragraph_containing — not brittle line numbers. Agents acquire an edit lease (one at a time), submit operations against a base revision, and the server creates a new version.
• Cloud Personas — server-side AI reviewers (security, scalability, routing) that automatically review plans when they reach certain statuses, or on demand.
• Realtime — comments, edits, and status changes broadcast instantly to all viewers via Turbo Streams.
• Full provenance — every version records the actor (human, local agent, or cloud persona), the AI model used, the prompt, and which comments triggered the change.

Tech Stack

• Ruby on Rails 8+ — importmaps, Hotwire, Stimulus
• MySQL 8+ — UUID primary keys
• SolidQueue — background jobs
• SolidCable — ActionCable adapter

Installation

Add to your Gemfile:

gem "coplan-engine", require: "coplan"

See the Host App Integration Guide for full setup instructions.

Optional integrations

• coplan-slack adds signed Slack Events API handling and rich link unfurls without coupling Slack to the core engine.

Development Setup

bin/setup
bin/rails db:seed
bin/dev

Sign in with any @example.com email (stub OIDC).

For microphone dictation, start bin/dev from a shell with OPENAI_API_KEY set, or configure openai.api_key in Rails credentials. Both the plan microphone and the composer’s Dictate button then record audio for server transcription. If you add the key after starting the server, restart it and reload the plan. Without a key, dictation uses the browser’s speech service, which may be unavailable in embedded browsers. Check configuration without printing the key:

bin/rails runner 'puts CoPlan::Ai.available?'

Tests

bundle exec rspec

See CONTRIBUTING.md for pull request, spec, and visual testing requirements. Interactive features are tested with JavaScript-enabled browser specs in spec/system/.

API

Agents authenticate with Authorization: Bearer <token>. Key endpoints:

• GET /api/v1/plans/:id — read a plan
• POST /api/v1/plans/:id/lease — acquire edit lease
• POST /api/v1/plans/:id/operations — apply semantic edits
• POST /api/v1/plans/:id/comments — comment on a plan

See docs/PLAN.md for full architecture.

Project Resources

Resource	Description
CODEOWNERS	Project lead(s)
GOVERNANCE.md	Project governance
LICENSE	Apache License, Version 2.0