Opencitations vs Anna's Archive
A side-by-side look at the Opencitations and Anna's Archive MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose Opencitations for research work as a local process; choose Anna's Archive for research as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose Opencitations when
- You need dedicated capabilities in the Research domain.
- You prefer a local stdio subprocess transport.
- You want tools like
references, citations, citation_count.
Choose Anna's Archive when
- You need dedicated capabilities in the Research domain.
- You prefer a local stdio subprocess transport.
- You have the keys it needs:
ANNAS_SECRET_KEY. - You want tools like
account_status, article_download, article_search.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | Research | Research |
| Quality signal | 59/100 · Good | 63/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | Not declared | Not declared |
| Pricing | Not declared | Not declared |
| Required env vars | None listed | ANNAS_SECRET_KEY |
| Verified owner | Community listing | Community listing |
| GitHub stars | 0 | 3 |
| Directory activity | 1 views 0 installs 0 upvotes | 1 views 0 installs 0 upvotes |
| Tools | 6 | 7 |
| Full listing | View Opencitations | View Anna's Archive |
Tools & capabilities
Opencitations tools 6
references"What does paper [DOI] cite" / "references in [paper]" / "what sources does this paper use" — DOIs cited BY the given DOI (the paper's reference list / bibliography). Use for citation-graph traversal, literature review, source tracking.citations"Who cites paper [DOI]" / "what papers reference [DOI]" / "incoming citations to [paper]" / "what work has cited [study]" — DOIs that CITE the given DOI (reverse-direction from references). Use for impact analysis, follow-on research discovery, "is this paper influential" questions.citation_count"How many times has paper [DOI] been cited" / "citation count for [paper]" / "is [study] highly cited" — incoming citation count for a DOI. Fast version of `citations` when you only need the number, not the citing DOIs.references_count"How many references does paper [DOI] have" / "how big is the bibliography of [paper]" — outgoing reference count for a DOI. Fast version of `references` when you only need the number.metadata"Get paper info for [DOI]" / "bibliographic details for [paper]" / "title / authors / year of [DOI]" — bibliographic metadata for one or more DOIs (up to 50 at once). Returns title, authors, year, journal, publisher.citationFetch one citation record by its Open Citation Identifier (OCI — a compound ID of the form citing-DOI__cited-DOI). Returns citing/cited DOI pair, creation date, and journal self-citation flag. Use `citations` or `references` instead when you only have a DOI.
Anna's Archive tools 7
account_statusShow the account's membership and how many fast downloads it has left in its rolling window. Check it before downloading many files.article_downloadDownload a selected paper by exactly one of doi or hash. The hash field accepts a bare MD5 or an Anna's Archive /md5/ page URL. Resolves a DOI to its hash, then returns an existing file in ANNAS_DOWNLOAD_PATH if its full MD5 matches, otherwise downloads under a unique name. Returns path and bytes; downloads_left is omitted on local reuse. Optional title and format control a new file's name.article_searchFind a paper by DOI (including DOI URLs), or search journal articles by keywords, author, title or year. DOI lookup returns one paper; keyword search returns one page. Set include_stats to add public per-file downloads, quality votes, reports, lists and comments. Compare metadata before downloading by hash or DOI.book_detailsGet the full record for a search hit: ISBNs, DOI, OCLC and other identifiers, edition, year, full description, subjects, alternative titles, problems reported for the file, and download and quality counts. Accepts a hash from book_search or article_search, or an id from metadata_search.book_downloadDownload the selected book using its MD5 hash or Anna's Archive /md5/ page URL in hash. Returns an existing file in ANNAS_DOWNLOAD_PATH if its full MD5 matches, otherwise downloads a verified copy under a unique name. Returns path and bytes; downloads_left is omitted on local reuse. Format sets the extension; it does not convert the file.book_searchSearch books, textbooks, manuals and standards by title, author or topic, optionally filtered by format, language, content type, source library or year and sorted. Returns one page with hash, format, year, fast_download and metadata. Set include_stats to add public per-file downloads, quality votes, reports, lists and comments. Pass a selected hash to book_download, or to book_details for ISBNs, edition and file problems.metadata_searchSearch library catalogs (Open Library, WorldCat, ISBNdb, Goodreads, Google Books and others) for books, including ones with no downloadable file. Use it to find ISBNs, editions and publication details, then search book_search by ISBN or title for files. Pass an id to book_details for identifiers.
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
Opencitations
{
"mcpServers": {
"opencitations": {
"command": "npx",
"args": [
"-y",
"@pipeworx/mcp-opencitations"
]
}
}
}
Anna's Archive
{
"mcpServers": {
"anna-s-archive": {
"command": "npx",
"args": [
"-y",
"annas-mcp"
],
"env": {
"ANNAS_SECRET_KEY": "YOUR_ANNAS_SECRET_KEY_HERE"
}
}
}
}
Frequently asked questions
Opencitations is categorized under Research and uses a local stdio subprocess. Anna's Archive belongs to Research and uses a local stdio subprocess. Pick Opencitations for research work and Anna's Archive for research.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client.
Opencitations has no declared pricing — check the project's own site. Anna's Archive has no declared pricing — check the project's own site. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add opencitations and anna-s-archive as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, Opencitations has a quality signal of 59/100 (Good) with 1 views, 0 installs and 0 GitHub stars. Anna's Archive has 63/100 (Good) with 1 views, 0 installs and 3 GitHub stars.