Opportunities › Code review workflow for AI-assisted development › Proposed app
Penmark
Annotate AI-made diffs from your terminal and send notes back to the agent
- Score
- 32
- confidence 56
- Evidence
- 7
- items on the page
- Rivals
- 2
- named in sources
- First version
- 25 d
- estimate
- Type
- Desktop and mobile
- PWA: on computers and phones alike
- Market since
- 2025
- New market · AI estimate
ScreensConcept
Desktop and mobile: Core review and feedback on code diffs happens in the terminal on desktop, but the app is designed for developers to continue and follow up on phones, making both essential to the workflow. Sample screens on a computer and a phone, in the proposed brand. Their numbers are sample data.
Review: auth/session.ts
Round 13 open
About this appAI proposal
Penmark is a review loop for code written by AI agents. A small command-line bridge runs beside your agent in the terminal, collects its changes as a diff, and lets you mark lines or hunks with a note: fix, explain, question or reject. One command hands every note back to the agent as a structured prompt.
When the agent revises, Penmark shows only what changed since your last pass, so you check your own notes instead of rereading the whole diff. A web view, installable as a PWA, lets you continue a review from a phone or second screen while the session stays tied to your terminal.
It is for developers who already work with terminal agents such as Claude Code and find that separate diff apps break their flow or make feedback clumsy. Any agent that can read a text prompt can take the notes.
- Tagline
- Review the agent's work without leaving the terminal.
- Voice
- PlainPreciseCalm
- Why this name
- A pen mark is the small note a reviewer leaves in a margin. The name is two plain words joined, easy to say and type as a command.
In the first version
Members say which features they would use. It tells PWAS what people want; it changes no score.
Terminal-first review
Start a review with one command beside your agent. Step through hunks with the keyboard and stay in the session.
No member yet
Line and hunk notes
Attach a note to one line or a whole hunk, tagged fix, explain, question or reject, so the agent knows what you want.
No member yet
One-command feedback
Send all open notes back as a structured prompt with file paths and line ranges. No copying between apps.
No member yet
Round-by-round diffs
After each revision, see only what changed since your last pass, with each note marked resolved, open or ignored.
No member yet
Brand identityAI proposal
Check the name against trademark registers before using it.
Palette
#2F5D50Pine · primary#F7F3EAPaper · surface#1F2420Ink · text#D9822BMarker orange · accent#3B6EA8Slate blue · data#B3402FBrick · reject / removed
Typography
Aa
Penmark
PricingAI proposal
The material gives no competitor prices or willingness to pay. These tiers are a starting point to test, based on the inferred freemium and team subscription model.
Solo
Free
- Terminal bridge
- Line and hunk notes
- Send notes to one agent
- Last 5 reviews kept
Pro
$12 a month
- Unlimited review history
- Round-by-round diffs
- PWA sync across devices
- Plan review
Team
$24 a month
- Per seat
- Shared review sessions
- Note templates for the team
- Admin and billing
Would you pay Pro · $12 a month?
Your answer tells PWAS which prices people accept. It changes no score.
No answers yet.
What it could be worthEstimate
What a software business making this much sells for today, from real deals. Pick a monthly revenue.
If it makes
Worth about
$190,000
Sale range $132,000 to $263,000
$120,000 a year in revenue
From 87 software businesses listed and sold on Empire Flippers in the last year, revenue vetted by the broker: they sell for about 19× their monthly revenue, most between 13× and 26×.
Measured on profit, the middle deal is 32× monthly net profit: about 2.7 years of profit.
What products in this market make
- CodeRabbitEstimate$4,166,667 a month, worth about $79,200,000 at that multiple · sacra.com
An estimate, not an offer or financial advice. A real price depends on profit, growth, churn, how much of the work is the owner's, and the buyer.
How it would growAI proposal
How the product would reach new customers through its own use, and how the first ones would be found. A plan to test, not a result.
- Built-in loop
- Shared outputs. Users share a review link or exported notes in pull requests and chats. Teammates open the read-only review to see what was asked of the agent and how it changed.
- Do they become customers?
- Viewers are developers and could install the CLI, but a link opened once is exposure, not acquisition. Test how many viewers run the install command and start their own review.
- First customers
- Solo developers and small teams of 2 to 10 engineers who use a terminal coding agent daily and review its changes by hand.
- Where to reach them
- Hacker News and Show HN: Post a demo of the review loop in the thread where the need was raised and offer the free tier.
- Agent user communities: Share short screen recordings in Discords and forums for terminal coding agents.
- Open-source README badge: Offer a small badge and an export that repos can include to show reviewed agent changes.
- First milestone
- Fifty weekly active free users and five paying Pro or Team users, from terminal-agent users, within eight weeks of launch.
Why people already pay for this
- VerifiedHacker News post received 17 points and 4 comments
- Public claimDevelopers need to review AI-generated code changes within their terminal workflow rather than switching to separate applications
- Public claimExisting code review tools interrupt the terminal workflow or have inefficient feedback loops
- Public claimThere is a use case for planning review integrated with AI agents
- AI inference
Tech stack
Every proposal builds on the same PWA base, installable from the browser on any phone or computer. Dashed boxes are what this app adds.
- AppNext.js and TypeScript
- PWAManifest and service worker
- UITailwind CSS
- Data and authSupabase Postgres
- PaymentsStripe
- EmailResend
- HostingVercel
- This app · Terminal bridgeCross-platform CLI distributed via npmThe core flow runs in the terminal, so a local command-line tool must capture diffs and return notes to the agent.
- This app · Live syncRealtime channel (Supabase Realtime)Keeps the terminal session and the PWA view of the same review in step.
RisksAI inference
- PlatformAgent vendors may add built-in diff review and annotation to their own terminal tools, removing the need for a separate product.
- TechnicalReturning notes reliably to many different agents and terminal setups may need per-agent adapters and ongoing upkeep.
- CommercialDemand is only lightly shown: one Hacker News post with 17 points and 4 comments. Developers may expect this kind of tool to be free or open source.
- DataSyncing diffs to a web view moves private source code to a server. Many teams will want local-only mode or strong guarantees before they agree.
- TechnicalA PWA cannot live inside the terminal. The value depends on the CLI bridge, and the web view must prove useful as a companion.
Everything marked AI proposal or AI inference was written by a model from the evidence on the opportunity page. The proposed name must be checked against trademark registers before it is used.