Replace expensive subscriptions
scalpels.app
Capstan
One Laravel application your organisation forks, deploys to its own Laravel Cloud account, and switches on by feature flag. Today it does two things: hosts AI-generated HTML behind signed, expiring links in a cookieless sandbox origin, and runs a signed message bus that your command-line agents poll to hand work to each other.
Work in progress. Available to teams with Unlimited.
- Replaces
- Per-seat sharing and agent-messaging tools
- Runs on
- Your Laravel Cloud account
- Needs
- Compute · Database · Queue · Object storage · Scheduler
What it does today
Two feature flags, both off until you turn them on
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Sandboxed artifact hosting
Post HTML over the API and it is stored privately and served from a separate cookieless origin inside a locked-down frame.
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Two-mode gating
Each artifact is visible to any signed-in member or to anyone holding a signed link, with an optional hard expiry.
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An agent message bus
Command-line agents poll for signed envelopes addressed to inboxes they own, with first-claim ownership and same-user pools.
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A liveness map
Every registered agent shows green, red or pending from poll recency plus a nonce probe swept every minute.
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One-paste agent onboarding
An owner generates a short-lived snippet that authorises in the browser, writes a token locally, and installs the poller.
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One organisation, real roles
The first registrant becomes owner; owners and admins invite by code or email, change roles, and revoke tokens.
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Contained, not sanitised
CSPCapstan never tries to clean AI-generated HTML. It isolates it: a separate host, no session cookie, no outbound connections, no form submission, frame ancestors pinned to the app, and a five-minute signed content URL.
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Deterministic mail for agents
Envelopes are canonical JSON signed with a server key, ordered by receipt time, and deduplicated by acknowledgement. Backdating cannot promote a message, and a lost response is recovered by redelivery.
Capstan vs. the incumbents
Two working parts, honestly compared
Notion, Slack and Confluence are workspaces, and Capstan is not one yet. It does two narrow things — render untrusted HTML safely behind links you control, and give agents an auditable way to address each other — on infrastructure you own. Everything else on their feature list, it does not do.
| Feature | Capstan Self-hosted, MIT, experimental | Notion Hosted | Slack Hosted | Confluence Hosted |
|---|---|---|---|---|
| Render arbitrary AI-generated HTML safely the row we built | Does this well:Isolated origin | Not built:Not offered | Not built:Not offered | Partly, or with a caveat:Limited embeds |
| Signed, expiring share links the row we built | Does this well:Per artifact | Partly, or with a caveat:Public links | Not built:Not offered | Partly, or with a caveat:Public links |
| Agent-to-agent messaging with liveness the row we built | Does this well:Signed, polled, probed | Not built:Not offered | Partly, or with a caveat:Bots in channels | Not built:Not offered |
| Browse, search and manage what was shared we did not build this | Not built:API only | Does this well:Included | Does this well:Included | Does this well:Included |
| Knowledge base, comments, page history we did not build this | Not built:Not built | Does this well:Their core strength | Partly, or with a caveat:Canvases | Does this well:Their core strength |
| Postmortems and incident workflow we did not build this | Not built:Not built | Partly, or with a caveat:Templates | Partly, or with a caveat:Via integrations | Partly, or with a caveat:Templates |
| How agents connect | Partly, or with a caveat:REST with a token | Does this well:API and MCP | Does this well:API and apps | Does this well:API and MCP |
| Where your data lives | Does this well:Your Cloud account | Works, but on their terms:Residency on Enterprise | Works, but on their terms:Residency on Business+ | Works, but on their terms:Their cloud |
| Cost of adding a person | Does this well:Nothing | Works, but on their terms:Per seat | Works, but on their terms:Per seat | Works, but on their terms:Per seat |
| Who is on call for the tool itself | Partly, or with a caveat:You are | Does this well:They are | Does this well:They are | Does this well:They are |
- Does this well
- Partly, or with a caveat
- Not built
- Works, but on their terms
The honest test
Capstan is experimental and pre-launch. If these are all true, it is worth a pilot on infrastructure you already pay for.
- Your agents emit HTML reports that must never leak cookies or reach your app's origin, and you want them shareable inside the organisation.
- You run more than one command-line agent and need a plain, auditable way for them to address each other and prove they are alive.
- You can accept a placeholder dashboard and toggles that live in environment variables.
Then a fork costs you a subscription you were not going to use anyway. The rest of the pitch arrives when it is genuinely built, not before.
Keep paying them if
These are the parts that do not exist yet, and we are not going to pretend otherwise.
- You need a wiki, search, comments or page history.
- You need postmortems or any incident workflow.
- Your agents speak MCP and you do not want to write REST glue.
- You need non-technical staff to upload, find and delete shared documents in a UI.
Capstan is a security-first substrate with two working parts, not yet a workspace.
Be honest about it
You don't need us to run Capstan
The repository is public and MIT licensed. These are the steps, and you are welcome to spend the afternoon doing them by hand.
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1
Fork the Capstan repository into your own GitHub organisation.
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2
Deploy the fork to Laravel Cloud with its own compute, Postgres, queue, object storage and scheduler, plus a separate host for the render origin.
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3
Register first to become the owner, switch on the features you want, and connect an agent with the one-paste snippet.
Or buy Unlimited once. Scalpels forks it, provisions exactly what it needs on your Laravel Cloud account, and deploys it. The app and the infrastructure are yours either way — the only question is who spends the afternoon.
Deploy Capstan with Unlimited