A living plan
Requirements, rationale, and implementation status in one Markdown document that you and the agent both edit — version-tracked, never buried in a thread.
Planning-Driven Development
Plan with your
coding agent.
InPlan is a Markdown workspace where you and your AI coding agent shape requirements together — a living source of truth that tracks rationale, status, and changes, and stays consistent as the project grows.
Free local editor & CLI agent · open-core (AGPL)
AI writes code fast. Plans drift faster.
AI coding agents are great at generating code quickly — but they struggle when requirements evolve, context grows, and decisions accumulate. Traditional AI workflows are built around linear conversations, so it's hard to track requirements, rationale, implementation status, and changes in a way that stays consistent as a project grows.
InPlan introduces Planning-Driven Development: requirements become a living, collaborative document that evolves alongside the code. Inspired by shared document editors and code review, it lets teams continuously refine plans, capture decisions, manage requirement updates separately from bug fixes, and maintain a reliable source of truth that neither humans nor AI agents can consistently hold in memory.
A plan you both edit — not a chat log
Inline comments & decisions
Discuss like a document review. Pose open questions, answer them, and capture why a decision was made — anchored to the exact text.
Human ⇄ agent collaboration
Work turn-by-turn or in real time, with Auto-accept or Review for every revision. Live presence shows when your agent is in the room.
Less implementation drift
Manage requirement changes deliberately and separately from bug fixes. The agent builds against an agreed, versioned spec — so intent and code stay aligned.
How it works
- 1
Draft the plan
Write requirements in Markdown. The agent proposes structure and raises open questions as inline comments.
- 2
Refine together
Comment, answer, and revise. Accept changes automatically or review each one — the plan converges as a shared decision record.
- 3
Build with confidence
The agent implements against the agreed source of truth, so refactoring is safer and the work stays adaptable without sacrificing correctness.
Simple, honest pricing
Free
$0
The open core
- Local Markdown editor
- Local CLI agent
- AGPL-3.0 — yours to run
Pro
$9.99/mo
For solo builders
- Managed cloud agent
- Real-time collaboration
- Plans synced across devices
Team
$17.99/seat
For teams
- Everything in Pro
- Shared org & roles
- Per active member
Frequently asked
What is InPlan?
InPlan (Interactive Planning Editor) is a Markdown workspace where you and your AI coding agent plan software together. Instead of a linear chat, requirements live in a collaborative document that tracks rationale, implementation status, and changes as the project grows.
What is Planning-Driven Development (PDD)?
A workflow where the requirements document is the living source of truth that evolves alongside the code. Teams continuously refine plans, capture decisions, and manage requirement updates separately from bug fixes — reducing implementation drift and keeping intent aligned with the code.
How does InPlan work with AI coding agents?
The agent reads and edits the same plan you do. It proposes structure and open questions as inline comments; you review, answer, and revise — in Turn or Instant cadence, with Auto-accept or Review. The agreed plan then guides implementation, so the agent builds against a reliable, versioned spec rather than a fading chat history.
Is InPlan open source?
Yes — InPlan is open-core. The editor and CLI are open source under AGPL-3.0-or-later (a commercial license is available for proprietary or closed-source use); the cloud collaboration and managed agent are paid plans.
How much does InPlan cost?
The local editor and CLI agent are free. Pro is $9.99/month for a managed cloud agent and real-time collaboration; Team is $17.99 per active member per month.