MCP servers for Claude Code · Research
Best research MCP server for Claude Code, tested
In ToolPassed's hands-on tests in Claude Code, arXiv MCP is our provisional candidate for research: it passed install, connect, tools and an agent task on 2026-10-20. We ran 4 research MCP servers in Claude Code; 3 passed every step; not a pass: Paper Search MCP (failed).
Last tested · runs from 2026-10-15 to 2026-10-22 · one run per server · How we test
Results in Claude Code
| Server | Claude Code |
|---|---|
| arXiv MCP Research | Passed 2026-10-20 · install, connect, tools, agent task |
| Hugging Face MCP Server Research | Passed 2026-10-22 · install, connect, tools, agent task |
| Simple arXiv MCP Research | Passed 2026-10-15 · install, connect, tools, agent task |
| Paper Search MCP Research | Failed 2026-10-15 · did not connect, so the agent task could not use it |
Dated results
- arXiv MCP passed in Claude Code on 2026-10-20 (Claude Code 2.1.296, arxiv-mcp-server 0.8.2, connected in 2.8s). Full result
- Hugging Face MCP Server passed in Claude Code on 2026-10-22 (Claude Code 2.1.296, mcp-remote 0.15.2, connected in 2.4s). Full result
- Simple arXiv MCP passed in Claude Code on 2026-10-15 (Claude Code 2.1.296, server reported v0.6.0, connect time not recorded). Full result
- Paper Search MCP failed in Claude Code on 2026-10-15 (Claude Code 2.1.296, package version not recorded, connect time not recorded). Full result
Why arXiv MCP is the candidate
arXiv MCP passed every step in Claude Code. It is the group’s site-wide candidate (judged 2026-10-20): Found 'Attention Is All You Need' and returned its arXiv ID (1706.03762) in both Claude Code and Cursor in 2 calls in total, and also passed in ChatGPT (Codex). Simple arXiv MCP passed both with 3 calls. Paper Search MCP failed to start in both clients on Oct 15 (its published uvx command crashes on current dependencies). Zotero MCP needs a local Zotero library and isn't tested. Confirmed Oct 20, 2026: a second run in Claude Code and Cursor passed both tasks again (arxiv-mcp-server 0.8.2).
Provisional: based on one dated run per app (no repeat runs yet), so treat it as a candidate, not a final pick. How we test.
Same servers in all 4 apps
| Server | Claude Code | Cursor | Claude Desktop | ChatGPT (Codex) |
|---|---|---|---|---|
| arXiv MCP Research | Passed 2026-10-20 · install, connect, tools, agent task | Passed 2026-10-20 · install, connect, tools, agent task | Passed 2026-10-18 · install, connect, tools, agent task | Passed 2026-10-15 · install, connect, tools, agent task |
| Hugging Face MCP Server Research | Passed 2026-10-22 · install, connect, tools, agent task | Passed 2026-10-22 · install, connect, tools, agent task | Not tested yet | Passed 2026-10-22 · install, connect, tools, agent task |
| Simple arXiv MCP Research | Passed 2026-10-15 · install, connect, tools, agent task | Passed 2026-10-15 · install, connect, tools, agent task | Passed 2026-10-18 · install, connect, tools, agent task | Passed 2026-10-19 · install, connect, tools, agent task |
| Paper Search MCP Research | Failed 2026-10-15 · did not connect, so the agent task could not use it | Failed 2026-10-15 · did not connect, so the agent task could not use it | Not tested yet | Failed 2026-10-22 · agent task failed (no successful call to this server's tools; answer missing ['1706.03762']; no tool result containing ['1706.03762']) |
What failed or is partial in Claude Code
- Paper Search MCP: failed on 2026-10-15. Recorded reason:
no successful call to this server's tools; no tool result containing ['1706.03762']
Install in Claude Code
The exact snippet we tested is on the arXiv MCP page (pick the Claude Code tab). Not connecting? Claude Code MCP troubleshooting.
Not tested in Claude Code yet
Perplexity MCP, Gemini Notebook MCP + CLI, Zotero MCP, Korean Law MCP, OpenCity Record, Reyda MCP, Arcmira MCP, Folklore Clinical Variant Interpretation MCP, PaperGraph MCP. Listed from their source; no result in Claude Code yet.
Questions
What is the best research MCP server for Claude Code?
In ToolPassed's hands-on tests in Claude Code, arXiv MCP is our provisional candidate for research: it passed install, connect, tools and an agent task on 2026-10-20. We ran 4 research MCP servers in Claude Code; 3 passed every step; not a pass: Paper Search MCP (failed).
Does arXiv MCP work with Claude Code?
arXiv MCP passed in Claude Code on 2026-10-20 (Claude Code 2.1.296, arxiv-mcp-server 0.8.2, connected in 2.8s).
Does Paper Search MCP work with Claude Code?
No, not in our test: Paper Search MCP failed in Claude Code on 2026-10-15 (Claude Code 2.1.296, package version not recorded, connect time not recorded). Recorded reason: no successful call to this server's tools; no tool result containing ['1706.03762']
More: all MCP servers tested in Claude Code · Research in every app · How we test