gutenberg-mcp-server
by cyanheads
README.md
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<h1>@cyanheads/gutenberg-mcp-server</h1>
<p><b>Search, browse, and read 78,000+ public-domain books from Project Gutenberg with full plain-text retrieval and offset/limit chunking via MCP. STDIO or Streamable HTTP.</b>
<div>4 Tools</div>
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[](./CHANGELOG.md) [](./LICENSE) [](https://github.com/users/cyanheads/packages/container/package/gutenberg-mcp-server) [](https://modelcontextprotocol.io/) [](https://www.npmjs.com/package/@cyanheads/gutenberg-mcp-server) [](https://www.typescriptlang.org/) [](https://bun.sh/)
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[](https://github.com/cyanheads/gutenberg-mcp-server/releases/latest/download/gutenberg-mcp-server.mcpb) [](https://cursor.com/en/install-mcp?name=gutenberg-mcp-server&config=eyJjb21tYW5kIjoibnB4IiwiYXJncyI6WyIteSIsIkBjeWFuaGVhZHMvZ3V0ZW5iZXJnLW1jcC1zZXJ2ZXIiXX0=) [](https://vscode.dev/redirect?url=vscode:mcp/install?%7B%22name%22%3A%22gutenberg-mcp-server%22%2C%22command%22%3A%22npx%22%2C%22args%22%3A%5B%22-y%22%2C%22%40cyanheads%2Fgutenberg-mcp-server%22%5D%7D)
[](https://www.npmjs.com/package/@cyanheads/mcp-ts-core)
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**Public Hosted Server:** [https://gutenberg.caseyjhand.com/mcp](https://gutenberg.caseyjhand.com/mcp)
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---
## Overview
Project Gutenberg's library of 78,000+ public-domain books. Search by title, author, topic, or language, fetch full book metadata, and read supported UTF-8 plain-text and HTML editions in manageable chunks.
### Tools
| Tool | Description |
|:-----|:------------|
| `gutenberg_search_books` | Search the catalog by title, author, topic, language, or author lifespan, with pagination and popularity sorting |
| `gutenberg_get_book` | Fetch complete metadata for a book by ID — authors, translators, editors, full formats map, subjects, copyright status |
| `gutenberg_get_text` | Retrieve a book's plain-text content stripped of license boilerplate, with offset/limit chunking |
| `gutenberg_browse_popular` | Browse the most-downloaded books, optionally filtered by language or topic |
---
## Capability reference
### `gutenberg_search_books` <sub>tool</sub>
- Filters: `query` (title/author words), `topic`, `languages` (ISO 639-1), `author_year_start`/`author_year_end`, `ids`, `mime_type`, and `copyright` (`"true"`, `"false"`, `"null"`; false means public domain in the USA). Live fallback rejects queries over four words
- `sort` is `popular` (default) or `ascending`/`descending` by Gutenberg ID. Up to 32 books per page; use `totalCount` and `hasMore` to page
- Each result carries `is_readable` (readable by `gutenberg_get_text`) and `has_plain_text`. Fails with `query_requires_mirror`, `page_out_of_range`, or `catalog_unavailable`
---
### `gutenberg_get_book` <sub>tool</sub>
- Returns the full `formats` map (MIME type → download URL) and authors, translators, and editors with birth/death years
- Also carries `is_readable`, `has_plain_text`, `summary`, `source_notes`, and `download_count` (downloads in the last 30 days, not lifetime)
- Fails with `not_found` or `catalog_unavailable`
---
### `gutenberg_get_text` <sub>tool</sub>
- Reads a book in `offset`/`limit` chunks (default `limit` 20,000, capped at 50,000), with the Gutenberg license header and footer stripped. `requestedLimit` and `appliedLimit` report both
- Prefers UTF-8 plain text and falls back to HTML converted to text; `sourceFormat` says which. Returns `totalChars`, `length`, `remainingChars`, `hasMore`, and `provenance` (ID, title, license URL). Use `length`, not `limit`, to compute the next `offset`
- Fails with `not_found`, `audio_book` (`media_type "Sound"`), `no_text_format`, `offset_out_of_range`, `text_file_not_found`, `text_fetch_rejected`, `invalid_text_response`, `text_fetch_failed`, or `catalog_unavailable`
---
### `gutenberg_browse_popular` <sub>tool</sub>
- Returns up to 32 titles (`limit`, default 20), most downloaded in the last 30 days first. `requestedLimit` and `appliedLimit` report the cap
- Optional `languages`, `topic`, `mime_type`, and `copyright` filters work as in search. `totalInCatalog` gives the full count
- Output reports truncation and carries a `continuation` pointing at `gutenberg_search_books`. Empty results succeed with a notice; fails with `catalog_unavailable`
---
## Features
Built on [`@cyanheads/mcp-ts-core`](https://github.com/cyanheads/mcp-ts-core): stdio and Streamable HTTP transports, pluggable auth (`none` / `jwt` / `oauth`), swappable storage (`in-memory`, `filesystem`, `Supabase`, `Cloudflare KV/R2/D1`), structured logging with optional OpenTelemetry tracing.
Gutenberg-specific:
- Searches and lookups read a local SQLite+FTS5 catalog mirror, falling back to [Gutendex](https://gutendex.com/) when the mirror is cold or missing a record
- Full plain-text retrieval from a Project Gutenberg content mirror, with UTF-8/HTML fallback
- Book text is cached per tenant, so later chunk reads skip the fetch
- No API key required
Agent-friendly output:
- `is_readable` on every search and browse result flags editions `gutenberg_get_text` can read
- `offset`, `length`, `totalChars`, `remainingChars`, and `hasMore` support reliable sequential reads
- `provenance` and `sourceFormat` on every text response cover attribution and fidelity
---
## Getting started
### Public Hosted Instance
A public instance is available at `https://gutenberg.caseyjhand.com/mcp` — no installation required. Point any MCP client at it via Streamable HTTP:
```json
{
"mcpServers": {
"gutenberg-mcp-server": {
"type": "streamable-http",
"url": "https://gutenberg.caseyjhand.com/mcp"
}
}
}
```
### Self-Hosted / Local
No API key required. Add the following to your MCP client configuration file:
```json
{
"mcpServers": {
"gutenberg-mcp-server": {
"type": "stdio",
"command": "bunx",
"args": ["@cyanheads/gutenberg-mcp-server@latest"],
"env": {
"MCP_TRANSPORT_TYPE": "stdio",
"MCP_LOG_LEVEL": "info"
}
}
}
}
```
Or with npx (no Bun required):
```json
{
"mcpServers": {
"gutenberg-mcp-server": {
"type": "stdio",
"command": "npx",
"args": ["-y", "@cyanheads/gutenberg-mcp-server@latest"],
"env": {
"MCP_TRANSPORT_TYPE": "stdio",
"MCP_LOG_LEVEL": "info"
}
}
}
}
```
Or with Docker:
```json
{
"mcpServers": {
"gutenberg-mcp-server": {
"type": "stdio",
"command": "docker",
"args": [
"run", "-i", "--rm",
"-e", "MCP_TRANSPORT_TYPE=stdio",
"ghcr.io/cyanheads/gutenberg-mcp-server:latest"
]
}
}
}
```
For Streamable HTTP, set the transport and start the server:
```sh
MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 bun run start:http
# Server listens at http://localhost:3010/mcp
```
### Prerequisites
- [Bun v1.4.0](https://bun.sh/) or higher (or Node.js v24+).
- No API key required — Project Gutenberg data is freely available.
### Installation
1. **Clone the repository:**
```sh
git clone https://github.com/cyanheads/gutenberg-mcp-server.git
```
2. **Navigate into the directory:**
```sh
cd gutenberg-mcp-server
```
3. **Install dependencies:**
```sh
bun install
```
4. **Configure environment:**
```sh
cp .env.example .env
# edit .env if you need to override any defaults
```
---
## Configuration
| Variable | Description | Default |
|:---------|:------------|:--------|
| `GUTENDEX_BASE_URL` | Gutendex catalog API base URL. | `https://gutendex.com/books/` |
| `GUTENBERG_TEXT_BASE_URL` | Content mirror serving the `/cache/epub` file tree. | `https://gutenberg.pglaf.org` |
| `GUTENBERG_MIRROR_PATH` | SQLite catalog path; use a persistent volume in containers. | `./.mirror/gutenberg-catalog.sqlite` |
| `GUTENBERG_MIRROR_REFRESH_CRON` | Cron schedule for in-process catalog refresh. | Unset |
| `MCP_TRANSPORT_TYPE` | Transport: `stdio` or `http`. | `stdio` |
| `MCP_SESSION_MODE` | HTTP session mode: `auto`, `stateful`, or `stateless`. Overrides the `stateless` posture the server declares in `createApp()`. | `stateless` |
| `MCP_HTTP_PORT` | Port for HTTP server. | `3010` |
| `MCP_AUTH_MODE` | Auth mode: `none`, `jwt`, or `oauth`. | `none` |
| `MCP_LOG_LEVEL` | Log level (RFC 5424). | `info` |
| `LOGS_DIR` | Directory for log files (Node.js only). | `<project-root>/logs` |
| `STORAGE_PROVIDER_TYPE` | Storage backend. | `in-memory` |
| `OTEL_ENABLED` | Enable [OpenTelemetry instrumentation](https://github.com/cyanheads/mcp-ts-core/tree/main/docs/telemetry). | `false` |
Build the local catalog with `bun run mirror:init` and check it with `bun run mirror:verify`. The server never harvests on startup, and uses Gutendex until the first harvest completes. Keep the catalog up to date with `bun run mirror:refresh` on a host scheduler, or set `GUTENBERG_MIRROR_REFRESH_CRON`.
---
## Running the server
### Local development
- **Build and run:**
```sh
# One-time build
bun run rebuild
# Run the built server
bun run start:stdio
# or
bun run start:http
```
- **Run checks and tests:**
```sh
bun run devcheck # Lint, format, typecheck, security
bun run test # Vitest test suite
bun run lint:mcp # Validate MCP definitions against spec
```
### Docker
```sh
docker build -t gutenberg-mcp-server .
docker run --rm -p 3010:3010 gutenberg-mcp-server
```
The Dockerfile defaults to HTTP transport, stateless session mode, and logs to `/var/log/gutenberg-mcp-server`. OpenTelemetry peer dependencies are installed by default — build with `--build-arg OTEL_ENABLED=false` to omit them.
---
## Project structure
| Directory | Purpose |
|:----------|:--------|
| `src/index.ts` | `createApp()` entry point — registers tools and inits services. |
| `src/config/server-config.ts` | Server-specific environment variable parsing (Gutendex and file-server URL overrides). |
| `src/mcp-server/tools/definitions/` | Tool definitions (`*.tool.ts`). |
| `src/services/gutendex/` | Gutendex catalog API client — search and book metadata. |
| `src/services/catalog-mirror/` | Local SQLite+FTS5 catalog mirror — RDF ingestion and read helpers. |
| `src/services/gutenberg-text/` | Full plain-text retrieval, boilerplate stripping, tenant-scoped caching, and chunking. |
| `tests/` | Unit and integration tests mirroring `src/`. |
---
## Development guide
See [`CLAUDE.md`](./CLAUDE.md) / [`AGENTS.md`](./AGENTS.md) for development guidelines and architectural rules. The short version:
- Handlers throw, framework catches — no `try/catch` in tool logic
- Use `ctx.log` for request-scoped logging, `ctx.state` for tenant-scoped storage
- Register new tools via the entry arrays in `src/index.ts`
- Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields
---
## Contributing
Issues are welcome. Run checks and tests before submitting:
```sh
bun run devcheck
bun run test
```
---
## Data attribution
Data from [Project Gutenberg](https://www.gutenberg.org/) is in the public domain. Catalog metadata sourced from [Gutendex](https://gutendex.com/) (MIT license).
---
## License
Apache-2.0 — see [LICENSE](LICENSE) for details.
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