Ebook File Check

Validate an EPUB from a public URL or chat attachment against the EPUB 2/3 specification using EPUBCheck, with exact rule IDs and file locations, or compare…

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What it can do

  • Ebook Check: Validates one EPUB (a directly hosted public URL or a file attached in chat) against the EPUB 2/3 specification using a pinned local EPUBCheck 5.3.0 engine run in a no-network sandbox. Ea
  • Ebook Compare: Runs the identical pinned EPUBCheck 5.3.0 validation over exactly two EPUB builds (directly hosted public URLs or files attached in chat, baseline first, revised second) sequentially un

What data it sees

Do you need an account

No: the server works without sign-in

Validate an EPUB from a public URL or chat attachment against the EPUB 2/3 specification using EPUBCheck, with exact rule IDs and file locations, or compare two builds. A pass does not guarantee accessibility, visual rendering, distributor acceptance, or editorial quality.

How to connect

How to connect Ebook File Check to Claude

The server address to paste into Claude settings:

https://epub-check--powmcp.run.tools

  1. Open Claude (claude.ai or the desktop app).
  2. Go to Settings → Connectors.
  3. Click Add custom connector.
  4. Paste the server address copied below into Remote MCP server URL and click Add.
  5. In a chat, click + → Connectors and switch the new connector on.

Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

Authorization

After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

How to connect Ebook File Check to ChatGPT

The server address to paste into ChatGPT settings:

https://epub-check--powmcp.run.tools

  1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
  2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
  3. Open Settings → Connectors and click Create.
  4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
  5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
  6. In a new chat open + → Apps/Connectors and enable the connector.

OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

Authorization

On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

How to connect Ebook File Check to Cursor

The server address to paste into Cursor settings:

https://epub-check--powmcp.run.tools

Fastest: click Open in Cursor below and confirm the prompt.

Manually:

  1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
  2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
  3. Save the file. The server appears in the MCP list; authorize it there if asked.

Authorization

If the service needs sign-in, an authorize button appears next to the server in the MCP list.

Server tool list (2)

Raw names from tools/list. Only developers need these.

ebook_checkValidates one EPUB (a directly hosted public URL or a file attached in chat) against the EPUB 2/3 specification using a pinned local EPUBCheck 5.3.0 engine run in a no-network sandbox. Each call takes exactly one source: the url parameter or the file attachment, never both. Returns the automated verdict: pass boolean, EPUB version, message counts by severity (fatal/error/warning/usage), findings grouped most-severe-first with EPUBCheck rule id (RSC-005, OPF-014, …), file path and line/column, plus a structural inventory (spine items, media types, remote-resource state), SHA-256 of the exact bytes, and truncation metadata. Use for one-file readiness and diagnosis: 'is this ebook valid', 'does this EPUB have specification problems before upload', 'what is wrong with it'. A pass means only that the bytes satisfied the automated profile; it never renders the book, judges accessibility, or guarantees any store will accept it, and human review of how the book reads and looks is always required. Downloads and validates a live EPUB in about five to seven seconds, hard-bounded at the 110-second call deadline.
ebook_compareRuns the identical pinned EPUBCheck 5.3.0 validation over exactly two EPUB builds (directly hosted public URLs or files attached in chat, baseline first, revised second) sequentially under one shared 110-second deadline, then reports which spec findings regressed or were fixed between them. Returns per-build hashes, EPUB versions, pass verdicts and severity counts, a regressions list (rules that appear or worsen in the revised build) and a fixed list (rules removed or reduced), and a ranking by pass state then fewer blocking findings. Use for 'did my re-export get worse', 'which build has fewer problems', and revision-over-revision questions. The ranking orders automated conformance only (it never means one build renders, reads, or sells better), and when both builds tie on pass state and blocking count it names no winner rather than crowning the first submission. It also flags when the two files declare different titles, since that usually means they are not two builds of one book. Human review remains required for both builds. A comparison measures about ten to fifteen seconds, hard-bounded at the shared 110-second deadline.