prepublish-mcp
Audit a YouTube script before you record it, from inside your AI client.
Prepublish is a remote MCP server. It reads a draft that does not exist as avideo yet and returns hook, structure and pacing scores, the passages mostlikely to lose viewers, an inauthentic-content check, a YouTube policypre-flight that cites YouTube's own published pages, and a words-to-runtimecalculator built on measured speaking rates.
Every other YouTube MCP server fetches the transcript of a video that isalready published. This one reads the script you have not filmed.
Free, anonymous, no API key, no account.
Install
Claude Code, one command:
claude mcp add --transport http prepublish https://mcp.prepublish.ai
Cursor, VS Code, Windsurf, Claude Code project scope, or anything thatreads an mcpServers object:
{
"mcpServers": {
"prepublish": {
"type": "http",
"url": "https://mcp.prepublish.ai"
}
}
}
Claude Desktop: add a custom connector under Customize, then Connectors,and paste https://mcp.prepublish.ai.
Codex CLI, ~/.codex/config.toml:
[mcp_servers.prepublish]
url = "https://mcp.prepublish.ai"
Clients that can only launch a command use the stdio bridge in thisrepository. It needs Node 20 or newer and forwards to the same endpoint:
{
"mcpServers": {
"prepublish": {
"command": "npx",
"args": ["-y", "prepublish-mcp"]
}
}
}
Agents installing this on a user's behalf should readllms-install.md.
Check it worked
Ask for a runtime estimate: "Use prepublish to convert 1500 words into aruntime range." script_runtime is local arithmetic, never rate limited, andreturns three estimates. If that answers, the connection is good.
Tools
| Tool | Cost | What it returns |
|---|---|---|
audit_script |
AI-backed | Full audit of a finished draft: hook, structure and pacing scores, an attention-risk map naming the passages most likely to lose viewers, and a rewrite. Returns the analysis and its id |
get_audit |
free | Collect an earlier audit by analysis_id |
audit_hook |
AI-backed | Per-sentence attention pull across the opening, curiosity gap, payoff distance, a grade, and rewritten alternatives |
check_authenticity |
AI-backed | Reused, templated or mass-produced content risk, with the quotes that fired each signal |
policy_preflight |
AI-backed | Which YouTube policy families a script touches, each citing YouTube's own page |
script_runtime |
free, local | Words to runtime and runtime to a word budget, at 160, 181 and 201 words per minute measured across 349 videos |
audit_script asks for an email address, because the full audit is released byemail. The other five do not.
What it does not do
Every AI-backed response carries the same notice, and it is worth stating heretoo. These checks are text-only. They map relative attention risk inside anunrecorded script. They do not measure or predict the retention a publishedvideo will get, and no output here is a forecast of views, watch time orrevenue.
Nothing fetches a video, a transcript or a channel. Every tool reads text youpass it.
Limits
The free tier is published live at GET https://mcp.prepublish.ai, whichreturns a machine-readable server card with the current day's usage.
| Limit | Default |
|---|---|
| AI-backed calls per UTC day, across the whole endpoint | 100 |
| AI-backed calls per caller per 10 minutes | 6 |
script_runtime is local arithmetic and never counts against either.
A bearer token in PREPUBLISH_TOKEN raises the limits without changing thetool list.
When the daily cap is reached the tool returns an error that tells the modelnot to retry and names the web alternative for that day. Failures return thenext action rather than a stack trace.
Transport and protocol
Streamable HTTP, stateless. Supported revisions: 2025-11-25, 2025-06-18,2025-03-26, 2024-11-05. A client asking for a supported revision gets itback; anything else negotiates to the newest one implemented, and thenegotiated revision is reported identically in the response header and in theinitialize result.
The endpoint validates the Origin header. Requests without one, which isevery non-browser client, are always served. A browser origin that is notprepublish.ai is refused with 403, as the transport specification requires.An unsupported MCP-Protocol-Version header is a 400.
Aliases: https://prepublish.ai/mcp and https://mcp.prepublish.ai/mcp servethe same handler.
Development
The server itself lives in the Prepublish web application, not in thisrepository. What is here is the stdio bridge and the conformance suite thatholds the hosted endpoint to the specification.
npm install
npm run build
MCP_URL=https://mcp.prepublish.ai npm test
The suite drives the endpoint with the official MCP SDK client overStreamable HTTP, so the wire format is checked against the referenceimplementation rather than against our own assumptions. It covers thehandshake, tool discovery, schema shape, both directions of script_runtime,unknown-tool errors, the server card, batching rejection, notificationhandling, protocol negotiation in both directions, Origin validation, protocolversion validation, and the stdio bridge round trip.
One AI-backed test is skipped unless MCP_TEST_BILLABLE=1, because a real callcosts money and writes a row.
PREPUBLISH_MCP_URL overrides the upstream endpoint for the bridge. The bridgeadds and hides nothing: a test asserts its tool list equals the hosted one, soadding a tool on the server needs no release here.
Registry
Published to the official MCP registry as ai.prepublish/script-audit, aremote-only entry under the DNS-verified ai.prepublish namespace. Seeserver.json.
Links
- Documentation: https://prepublish.ai/mcp-server
- Privacy: https://prepublish.ai/privacy
- Contact: https://prepublish.ai/contact
License
MIT. See LICENSE.
