io.github.cyanheads/crossref-mcp-server
crossref-mcp-server
Resolve DOIs, search ~155M scholarly works, and fetch references via the Crossref REST API.
alive probed 2026-10-09 · HTTP 200
7tools
6.8ktokens in Claude Opus 5.5
6.9ktokens in Claude Code
3.4 %of a 200k context window
4.3ko200k_base estimate
249 msto initialize
68 msto list tools
- Endpoint
- https://crossref.caseyjhand.com/mcp (streamable-http)
- Host
- crossref.caseyjhand.com
- Protocol
- 2025-11-25
- Reports itself as
- crossref-mcp-server 0.4.2
- Capabilities
- logging, prompts, resources, tools
- Instructions
- 1 064 characters
- Claude count
- Claude Opus 5.5, measured 2026-10-05. Counted again when the tool definitions change. Method.
- Repository
- https://github.com/cyanheads/crossref-mcp-server
- Registry
- active, updated 2026-10-08 · registry entry
- Reachable
- 7 of the last 7 probes
Most expensive tools
| Tool | Tokens (o200k) | Share of this server |
|---|---|---|
| crossref_search_works | 1 189 | 28 % |
| crossref_search_funders | 925 | 22 % |
| crossref_search_journals | 772 | 18 % |
| crossref_get_work | 599 | 14 % |
| crossref_get_references | 392 | 9 % |
History
We add a row when the result changes. A server with no change keeps its last row.
| Probed | Result | Init | Tools | Claude | o200k |
|---|---|---|---|---|---|
| 2026-10-09 11:18 | alive | 613 ms | 7 | 6.8k | 4.3k |
| 2026-10-05 14:38 | alive | 249 ms | 7 | 6.8k | 4.3k |
| 2026-10-05 00:33 | alive | 300 ms | 7 | 4.3k | |
| 2026-10-04 10:04 | alive | 368 ms | 7 | 4.3k | |
| 2026-10-04 07:57 | alive | 363 ms | 7 | 4.3k | |
| 2026-10-03 20:37 | alive | 1.0 s | 7 | 4.3k | |
| 2026-10-03 17:53 | alive | 555 ms | 7 | 4.3k |
Badge and feed
[](https://mcpcost.ulehla.dev/s/io.github.cyanheads/crossref-mcp-server)
An entry for every probe that changed the result, the tool count or the token cost: Atom feed. Add it to a feed reader or a Slack RSS app to hear when the server stops answering or its tool set grows.