MCP

Same tool engine for Desktop (JSON-RPC) and Claude online (Streamable HTTP). Use the Remote MCP box above for Claude Connectors. Short link: ner.sh/mcp.

Endpoints

Desktop / CLI proxy (JSON-RPC 2.0) — POST to:

https://ner.sh/api/mcp

Auth header:

Authorization: Bearer <firebase-id-token | cli-session-token>

Claude online Connectors (Streamable HTTP) — connector URL:

https://ner.sh/api/mcp/streamable

Local dev: use dev-bypass as token when DEV_BYPASS_AUTH=true.

CLI / Claude sessions use a signed CLI session token (~30 days) issued after device-code login at /cli/auth.

Tools ↔ CLI

Images: an image slot (logoImage, a hero's or a block-media block's image) takes an https URL, a data:image URI, or a site path to an image file; anything else is refused. Pick the URL from list_site_media, never a made-up path. The editor chat shares these tools: an image attached in the chat uploads to the site's media first, and the agent gets its URL with the message.

Multi-page sites: add_canvas_section, remove_canvas_section, reorder_canvas_sections, and set_section_layout target the home page (pages[] entry with empty slug). They keep pages[] and composition.sections in sync. Use add_page / update_pages for other pages.

Page nav: every header's links derive from the pages, in the Pages tab's order, unless that header's links are customised. A page's parentId names a top-level page other than home and shows the page in a dropdown under it; nesting is one level (home never nests, and a page with children takes no parent) and never changes the path. nav: "hide" keeps a live page out of the nav; nav: "pin" keeps a child linked, at the top level, when its parent is left out. update_pages replaces the whole array, so send each page's parentId and nav back as get_site returned them, or the tree flattens. A write that breaks a nesting rule is refused and changes nothing.

Node styles: set_node_style sets real CSS on one node (a band, container or block) at a breakpoint: desktop (the default), tablet (below 64rem) or phone (below 48rem). Tablet and Phone inherit Desktop unless they set a value. Keys are CSS longhands (width, min-height, padding-top, background-color, box-shadow, font-size, position, top, and the rest of the list in tools/list), plus the shorthands padding, margin, border, border-width, border-style, border-color and border-radius. A value is a preset id that follows the design system (sm, md, lg, xl for spacing; md for the site radius; lg for the large shadow; full, screen) or a custom value the property accepts (240px, 16 / 9); unset clears a property at that breakpoint. "Make the hero taller on phone":

{ "slug": "typeshit", "instanceId": "hero-band-x1", "breakpoint": "phone", "set": { "min-height": "80vh" } }

An unknown key or a refused value answers invalid_args naming each key, with accepts listing what every key takes. The old --section-bg-style tokens are still accepted at Desktop and land in the node's styles like any other key: a token with a CSS equivalent on that node becomes the property (--section-bg on a band is its background-color), and the tokens components read (--section-divider, the gradient stops, the fonts) stay custom properties.

Page SEO: update_seo with page writes that page's seo. A page field left unset inherits the site's value; send "" to clear a text field or URL and robotsIndex: null to clear the flag. robotsIndex: false hides the page from search engines. A page with no ogImageUrl shares the site's image, or a generated card with the page title when the site has none. Page settings go live on the next publish, like every other edit.

Route implementation: src/app/api/mcp/route.ts (Desktop) · src/app/api/mcp/streamable/route.ts (Connectors) · site tools: src/app/api/mcp/siteTools.ts.

Claude online (Customize → Connectors)

Use remote MCP from claude.ai without the Desktop stdio package:

1. In Claude: Customize → Connectors → Add custom connector.
2. Name: nertia (anything).
3. URL: https://ner.sh/api/mcp/streamable
4. Leave OAuth Client ID / Secret blank (Nertia supports dynamic registration + sign-in).
5. Click Add, then Connect when prompted — sign in on www.nertia.ai (Google preferred if that’s how your nertia account works).
6. You should see Connected to Claude, then return to Claude and enable the connector → tools/list.

Nertia’s authorization server lives on ner.sh (/.well-known/oauth-authorization-server, /oauth/mcp/authorize, /api/oauth/mcp/token, /api/oauth/mcp/register). Access tokens are the same CLI session tokens Desktop uses.

Optional (beta): if your Claude plan shows Request headers, you can still paste Authorization: Bearer <cli-token> from npx @nersh/mcp login instead of OAuth.

Transport notes: Streamable HTTP uses JSON responses + durable mcp-session-id (stored in RTDB). Standalone GET/SSE is not offered (405) — that avoids Claude seeing an immediately-closed empty stream (“connection stopped working”).

Local Connectors dogfood: tunnel localhost:3000 publicly, or use production ner.sh after deploy. Dev bypass (Bearer dev-bypass) still works for direct HTTP tests when DEV_BYPASS_AUTH=true.

publish_from_github (Vantage)

Dispatches Publish Vantage from GitHub on ps2pdx/nertia (ubuntu runner builds James’s Next.js repo, syncs out/ to public/clients/vantagecompute, commits to main). Live at vantagecompute.nertia.ai. Target is nersh, not James’s S3/CloudFront on www.vantagecompute.ai.

1. Local sync (dev): ./scripts/sync-vantage-next-export.sh [path/to/out]
2. MCP (prod): publish_from_github { repo?, ref?, slug? } — admin or vantagecompute manager. Returns a GitHub Actions run URL in ~2s; build + commit ~2–3 min; Vercel deploy ~2 min after that. Allowlisted repos: ps2pdx/vantagecompute-website, jamesbeedy/vantagecompute-website.
3. Secret: NERTIA_GITHUB_PAT on Vercel with actions:write + contents:write on ps2pdx/nertia and read on the source repo.

Why not inline build on MCP? Claude Connectors times out before npm ci + npm run build finish on Vercel serverless (~3+ min). Dispatch returns immediately with a run link.

Webflow ZIP unpack (scripts/unpack-webflow-export.sh) is legacy staging only.

Claude Desktop (@nersh/mcp)

Install with npx — no repo path, no manual Firebase token after first login:

{
  "mcpServers": {
    "nertia": {
      "command": "npx",
      "args": ["-y", "@nersh/mcp"]
    }
  }
}

First run: opens https://ner.sh/cli/auth?code=… → sign in → token saved to ~/.config/nersh/credentials.json.

Re-login: npx @nersh/mcp login

Package: packages/mcp · publish name @nersh/mcp.

Local dev

{
  "mcpServers": {
    "nertia": {
      "command": "npx",
      "args": ["-y", "@nersh/mcp"],
      "env": {
        "NERTIA_MCP_URL": "http://localhost:3000/api/mcp",
        "NERTIA_MCP_TOKEN": "dev-bypass"
      }
    }
  }
}

Start emulator + dev server (npm run dev:setup). NERTIA_MCP_TOKEN=dev-bypass skips saved credentials.

Troubleshooting

Legacy stdio proxy

scripts/nertia-mcp-stdio.mjs is deprecated — use @nersh/mcp instead.

Blob import bootstrap

./scripts/import-client-url.sh vantagecompute https://www.vantagecompute.ai

Request flow

Claude Desktop → @nersh/mcp (stdio) → POST /api/mcp
Claude online  → Customize → Connectors → GET/POST /api/mcp/streamable
        │
        ▼
verifyToken → handleMcpJsonRpc (shared tools)
        │
        ▼
Firebase RTDB → hosted site updates

Quick reference

Desktop:   POST https://ner.sh/api/mcp
Connectors: https://ner.sh/api/mcp/streamable
Auth:      Bearer <firebase-id-token | cli-session-token>
Local:     Bearer dev-bypass (DEV_BYPASS_AUTH=true)
Login:     npx @nersh/mcp login  →  ~/.config/nersh/credentials.json
Tools:     add/remove/reorder sections, switch skin, set layout, get site/schema, list site media, update copy/seo, pages, pricing, import, publish, publish_from_github (Vantage)