Open Artifacts

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Open-source, self-hosted Claude Code Artifacts: let any coding agent publish self-contained HTML/Markdown pages to shareable URLs, protect them with passwords (zero-knowledge, client-side encryption), and keep them updated as the project they describe evolves. Runs entirely on Cloudflare (Workers + D1 + R2), fits in the free tier, no accounts anywhere.

Hosted or self-hosted. coda0.com is the official managed instance, run by the project — point your agent at it for zero-setup publishing. Or self-host the engine on your own Cloudflare account (see below); it's the same MIT-licensed code either way.

flowchart LR
  you["you"] -- "share the app's interaction flows as a page" --> agent["your agent"]
  agent -- "POST /api/artifacts" --> worker["your Worker"]
  worker -- "https://<instance>/a/3fKx9mQp2Wvb" --> url["shareable URL"]
  later["later: the flows change"] --> status["agent runs<br/>artifact.mjs status"]
  status -- "stale" --> regen["regenerates page"]
  regen -- "PUT (same id)" --> worker2["your Worker"]
  worker2 -- "same URL, v2" --> url

Give your agent the skill

npx skills add coda0HQ/open-artifacts -s using-open-artifacts   # project scope (.claude/skills/)
npx skills add coda0HQ/open-artifacts -s using-open-artifacts -g  # or user scope

Works with Claude Code and any agent supporting the Agent Skills standard. Then point it at an instance — the hosted one, or your own:

export OPEN_ARTIFACTS_URL=https://coda0.com   # hosted; or your self-hosted URL

No instance yet? references/deployment.md (bundled with the skill) lists three ways to get one: use the public shared instance with zero setup, self-host on your own Cloudflare account, or share a team instance, with a trust-model table for picking based on content sensitivity.

The bundled SKILL.md and references/design.md teach the agent the design philosophy: an expert-designer workflow (understand, explore, plan, build, verify), an explicit anti-AI-slop list, modern CSS power moves, and a 5-direction library (Editorial / Modern minimal / Human / Tech utility / Brutalist) with ready-to-paste OKLch palettes and font stacks for when no brand is specified. references/tokens.css is the shared token contract the Recipe builder injects into every HTML artifact before its theme fragment. Adapted from open-design, Claude's artifact-design skill, impeccable by Paul Bakaus (Apache-2.0, interaction-state and anti-pattern rules), Emil Kowalski (easing, frequency, and duration rules), and Apple WWDC 2018 Designing Fluid Interfaces (canvas gesture physics). Retargeted to this project's strict no-external-requests CSP.

Ask your agent to "publish this as an artifact" — it runs the bundled CLI:

node skills/using-open-artifacts/scripts/artifact.mjs validate \
  .artifacts/recipes/app-interactions.recipe.json
node skills/using-open-artifacts/scripts/artifact.mjs create \
  .artifacts/recipes/app-interactions.recipe.json

Every artifact is generated from a versioned JSON Recipe plus ordered fragments. The Recipe owns title, favicon, format, scope, watch globs, channel, level, Canvas mode, locality, and encryption policy. create and update compose and validate in memory, then send exactly one final publish request.

Deploy your own instance

git clone https://github.com/coda0HQ/open-artifacts && cd open-artifacts
pnpm install
npx wrangler d1 create open-artifacts        # put database_id into wrangler.jsonc
npx wrangler r2 bucket create open-artifacts-content
pnpm run deploy

The schema applies itself on first request — no migration step. To restrict who can create artifacts on your instance (updates are always restricted by per-artifact write tokens):

npx wrangler secret put CREATE_TOKEN         # then set OPEN_ARTIFACTS_TOKEN client-side

Local development: pnpm dev (state persists in .wrangler/state).

How it works

API

POST   /api/artifacts           { content, favicon, title?, description?, format?, label?, encrypted?, channel? }
                                → 201 { id, url, writeToken, version, channel? }
PUT    /api/artifacts/:id       same fields + baseVersion?/force?   (Bearer writeToken or channel token)
GET    /api/artifacts/:id       metadata + version history
GET    /api/artifacts/:id/raw   stored content (?v=N)
DELETE /api/artifacts/:id       (Bearer writeToken)
GET    /a/:id                   rendered page (?v=N)

encrypted is { salt, iv, iterations } (all base64/int) with base64 ciphertext as content. channel is a channel token (ch_...) that targets the artifact already bound to that channel, or binds a new one on first use. Max content size 4 MiB.

Security model

• Serving untrusted HTML on your own origin is the classic stored-XSS trap; every user-content response here carries the CSP sandbox directive (opaque origin — no cookies, no storage, no same-origin API calls) plus default-src 'none', connect-src 'none', X-Content-Type-Options: nosniff and Referrer-Policy: no-referrer.
• *.workers.dev is on the Public Suffix List, isolating your instance from other sites.
• Anyone with the URL of an unprotected artifact can read it (like an unlisted gist). Use --password for anything sensitive; title/favicon metadata stays plaintext.
• An open instance (no CREATE_TOKEN) lets anyone with the URL create pages. Set the secret for anything public-facing.

Development

pnpm test          # Worker integration tests (vitest + workerd)
pnpm test:cli      # skill CLI tests
pnpm typecheck
pnpm check         # biome lint + format

BDD scenarios live in tests/features/; the architecture decision record in docs/architecture.md.

MIT licensed.