OpenAlex MCP

An MCP server that lets Claude search OpenAlex: 250M+ scholarly works, plus authors, institutions, journals, funders and research grants.

Packaged as a one-click Claude Desktop extension. Read-only, no writes to anything.

Tools

Names are resolved to IDs automatically, since OpenAlex rejects filtering by name, and every result set echoes which entity was chosen along with the alternatives.

Related MCP server: arXiv Research Assistant MCP Server

Install

1. Get a free API key at https://openalex.org/settings/api. Keys have been mandatory since 13 February 2026.

2. Download openalex-search.mcpb from Releases.

3. Claude Desktop: Settings, Extensions, Advanced settings, Extension Developer, Install Extension.

4. Paste the key. Optionally set your email, a daily spend cap and call logging.

5. Restart Claude Desktop.

If an older version is already installed, uninstall it first. A stale registration can keep serving the previous server while the new bundle appears installed.

Design notes

Cost. OpenAlex bills per call: singleton free, list $0.0001, keyword search $0.001, semantic search far higher. A key includes $1.00 per day free. The server tracks actual spend from meta.cost_usd, enforces a rolling daily cap (default $0.25) with a pre-flight check so a blocked call costs nothing, and appends one CSV row per call to ~/.openalex-mcp/calls.csv. That log is also how the cap survives a restart.

Context. Tool schemas sit in the model's context on every turn, so they are kept terse and results are compact by default. Roughly 1.2k tokens of schema and ~45 tokens per result. detail: "full" restores verbose output per call.

Permissions. All six tools declare readOnlyHint: true and destructiveHint: false. Servers that ship no annotations get worst-case defaults applied, which is why unannotated servers prompt for approval on every tool.

Robustness. Timeouts span both the header exchange and the body read. An earlier version cleared the abort timer once headers arrived, which let a stalled body hang indefinitely. A select field the API rejects is dropped, the query retried and the field remembered, so a schema rename degrades rather than breaking every query.

Safety posture

The published build is the one that gets tested. There is no separate "unsafe" variant, and the internal build differs only in configuration defaults.

• Spend cap on by default, $0.25/day, checked before each call so a blocked request costs nothing. Removing it requires typing the literal word unlimited; a plain 0, an empty value or a typo falls back to the default rather than silently disabling the guard. While disabled, every response says so.

• API key redaction. The key travels as a query parameter, so it can surface inside errors produced by the HTTP stack. Everything reaching the model or the log is redacted first. Tested with a mock that echoes the full URL into an error.

• No silent degradation. If OpenAlex rejects a field, the server drops it and retries so the query still works, then reports what was dropped. A quiet drop is how a schema change stays invisible until it breaks something else.

• Read-only. Every tool is HTTP GET only and annotated readOnlyHint: true.

• Local logging only. The call log stays in your home directory and is gitignored. It records endpoint, cost and filter string, never the key.

• No HTTP server. Transport is stdio only. test/bundle.mjs asserts the shipped bundle contains no hono, serve-static or .listen(, which is why advisories against the SDK's HTTP transport do not reach users. See SECURITY.md for the npm audit assessment.

Public and internal builds

npm run pack            # openalex-search.mcpb          public defaults
npm run pack:internal   # openalex-search-internal.mcpb group defaults

Both bundle the same server/index.js. Only manifest.json and manifest.internal.json differ, in default budget and prefilled contact email. test/manifests.mjs fails the build if the server block, version or tool list ever diverge, because two codebases would mean fixing every bug twice while CI covers only one of them.

Testing

npm test                                   # mock suites, free, ~40s
node smoke-live.mjs YOUR_KEY               # real API contract, ~$0.02
node stress-live.mjs --key YOUR_KEY        # full server end to end, ~$0.05
node stress-live.mjs --key YOUR_KEY --tier full   # adds soak and batch, ~$0.15

Mock tests alone are not sufficient, and this is not a theoretical concern. OpenAlex removed the grants field from works in its Walden rewrite. Every mock suite stayed green and the extension returned HTTP 400 on every search in production, because the mocks encoded the schema as it used to be. smoke-live.mjs tests each select field individually against the live API for exactly this reason, and the scheduled workflow in .github/workflows/live-check.yml runs it weekly.

stress-live.mjs additionally checks cross-tool invariants that a single-tool test cannot: that search_works and count_by_year report the same total for identical filters, that yearly counts sum to that total, and that adding filters never increases the result count.

A worked example of why live testing matters, from v2.7.0. OpenAlex offers two ways to match free text: search= covers full text, while filter=title_and_abstract.search: does not. For one probe they returned 29,261 and 16,654 works. search_works used the first and count_by_year the second, so a year curve did not describe the same corpus as the hit list. The mock parity test passed throughout, because it normalised the free-text term away before comparing. Both tools now build the whole query through one function and echo a canonical Query: line derived from the parameters actually sent, and test/parity.mjs compares those lines verbatim.

Relationship to OpenAlex

This is an independent project. It is not affiliated with, endorsed by, or supported by OpenAlex or OurResearch, who build and operate OpenAlex. It is a third-party client that calls their public API.

Where to report what

Please do not send bugs in this client to OpenAlex. Their support handles a free service used by the whole research community, and misrouted reports cost them time that should go to the data. If you are unsure which side a problem sits on, open an issue here and it can be triaged.

Data-quality caveats worth knowing before reporting anything as a bug are in Known limits; fragmented author records in particular are an OpenAlex-side issue and are already documented upstream.

Using the API responsibly

• Bring your own key. None is bundled. Get one free at https://openalex.org/settings/api.

• Keep the spend cap. It defaults to $0.25/day and exists to stop an agent loop hammering a free service. If you fork this, leave it on.

• Keep an honest User-Agent. The server identifies itself as openalex-mcp/<version>, with your email appended if you set one, so OpenAlex can see what is generating traffic and contact you if something misbehaves. If you fork and change behaviour, change the User-Agent string too, so problems from your fork are not attributed to this project or to anyone else's deployment.

• Prefer the free calls. get_work by DOI is a free singleton lookup. Use it instead of a search when you already have the identifier.

Credit

OpenAlex data is released under CC0. If you use this tool in work you publish, cite OpenAlex rather than this client:

Priem, J., Piwowar, H., & Orr, R. (2022). OpenAlex: A fully-open index of scholarly works, authors, venues, institutions, and concepts. arXiv:2205.01833. https://doi.org/10.48550/arXiv.2205.01833

Known limits

• Author identity is fragmented. OpenAlex may split one researcher across many author records. Searching by name silently undercounts; in one measured case a name query returned 16 works where the ORCID returned 25. Pass an ORCID whenever you have one. OpenAlex is rewriting author disambiguation during 2026.

• Funding coverage is uneven. Award data depends on funders and publishers depositing grant metadata. An empty award result is evidence about deposit practice, not about the publication record.

• Abstracts are reconstructed from an inverted index, so spacing and punctuation can be imperfect. The DOI is authoritative.

Development

npm ci
npm test
npm run pack        # writes openalex-search.mcpb

The published artifact is the esbuild bundle in dist/, not server/index.js. Editing the source without rebuilding ships nothing.

Licence

MIT. See LICENSE.

The MIT licence covers this client only. It grants no rights over OpenAlex, their API, or their trademarks, and carries no warranty: if you deploy this and it misbehaves against a third-party service, that is on you.

Data from OpenAlex, released under CC0.