paperpal
This server exposes two MCP tools for paper discovery and metadata verification.
semantic_search_papers_on_huggingface: search Hugging Face papers semantically with a query; optionally settop_n(default 10); returns titles, summaries, IDs, and upvotes.fetch_paper_details_from_arxiv: fetch arXiv metadata/details for one arXiv ID (string) or multiple IDs (list of strings).
Note: this schema does not include the other README-documented paperpal tools such as top-tier venue search, daily papers, trending models, Semantic Scholar lookup, evidence cards, full text grep, or notes rendering.
Enables searching and accessing research papers from arXiv's database to aid in literature reviews and academic research
Provides access to research papers hosted on Hugging Face, allowing users to discover and discuss AI/ML research
Mentioned as a planned integration for future development, likely to support academic writing workflows
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@paperpalfind recent papers about large language model alignment"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
paperpal
ML literature research for agents and humans: find it, verify it, score it, cite it.
paperpal is a plugin for coding agents (Claude Code, Codex, and any MCP client). It gives your agent a research methodology and the tools to follow it:
Find: semantic search over top-tier venues (NeurIPS, ICML, ICLR, AISTATS, …), Hugging Face papers (with community upvotes), today's daily papers, trending models
Verify: arXiv metadata (current title and version, venue hints), Semantic Scholar (venue, citations), and full text via arxiv-txt.org with regex grep, so numbers get quoted in context
Score: an evidence card per paper (venue from three sources, citations, age, code link) with a suggested 1–5 credibility band. You or your agent make the final call.
Cite: a barebones notes template, rendered to a static HTML page where every citation is a clickable link. Select all → paste into Google Docs, and links and tables survive. LaTeX (
$..$,$$..$$) is rendered with KaTeX; only pages that contain math get a script.
LLMs can still hallucinate and semantic search is never perfect. paperpal is built around making every claim checkable.
Install
Claude Code
git clone https://github.com/jerpint/paperpal
claude --plugin-dir ./paperpalThe plugin registers the paperpal skill and the paperpal MCP server (run with uv).
Codex
paperpal ships a portable Agent Plugins 1.0.0 manifest and a local marketplace:
git clone https://github.com/jerpint/paperpal
codex plugin marketplace add ./paperpal
codex plugin add paperpal@paperpal-local
codex mcp list # → paperpalClaude Desktop, Cursor, or any MCP client
Add the server to your client's MCP config (for Claude Desktop on macOS, that's ~/Library/Application Support/Claude/claude_desktop_config.json; for Cursor, .cursor/mcp.json):
{
"mcpServers": {
"paperpal": {
"command": "uv",
"args": ["run", "--directory", "/path/to/paperpal", "paperpal-mcp"]
}
}
}Skill only
Any agent that reads the open skills format can use the methodology without the server: copy skills/paperpal/ into your agent's skills folder (e.g. .agents/skills/ for Codex). The skill falls back to the CLI.
CLI
cd paperpal && uv sync
uv run paperpal -hRequires uv and Python ≥ 3.11.
Related MCP server: Research Assistant
Use
Ask your agent things like:
"Find peer-reviewed evidence that alignment training reduces output diversity, and score each source."
"Was this arXiv paper accepted anywhere? Check the exact number it reports for X."
"Prep research notes on small language models for a Google Doc: pointers only, every citation linked."
Or drive it directly:
uv run paperpal top "persona consistency role-playing" --n 5 # top-tier venues
uv run paperpal hf "ternary quantization" --n 5 # Hugging Face papers
uv run paperpal daily # today's HF daily papers
uv run paperpal meta 2510.22954 # arXiv metadata + venue hints
uv run paperpal card 2510.22954 # evidence card → suggested band
uv run paperpal full 2310.11324 --grep "76 accuracy points" # verify a number in the full text
uv run paperpal new notes.md --title "My topic" # start from the template
uv run paperpal render notes.md # → notes.html (gdoc-pasteable)Tools
MCP tool | CLI | what it does |
|
| semantic search over top-tier venue papers (paperz) |
|
| Hugging Face papers search (recency, upvotes) |
|
| today's Hugging Face daily papers |
|
| trending models on the Hub |
|
| arXiv title, authors, versions, comment / journal-ref venue hints |
|
| Semantic Scholar venue and citation counts |
|
| credibility evidence + a suggested 1–5 band with reasons |
|
| abstract, categories and BibTeX (arxiv-txt) |
|
| full paper text, or regex matches with context |
|
| linkify citations and write static, gdoc-pasteable HTML |
— |
| create a notes doc from the template |
The methodology
The skill (skills/paperpal/SKILL.md) tells agents how to research. The full guide is METHODOLOGY.md, which also works standalone for humans. In short:
Primary sources only. Papers, model cards, repos, vendor posts. Blog summaries are leads, not citations.
Verify every kept item: metadata → top-tier venue → the exact number in the full text.
Score credibility (1–5) on venue, lab, public code and data, age, and replication. Build arguments on ≥4.5, hedge 3–4, and footnote or drop ≤2.
Tag everything:
source type:
[peer-reviewed][preprint][industry][secondary][news]status: known / inferred / unknown
Pointers, not prose, unless asked to write.
Every citation is a link. Render to static HTML before sharing.
Configuration
env var | purpose |
| optional Semantic Scholar API key. Unauthenticated requests share a small rate limit. |
paperpal throttles requests per host (arXiv ≈ 1 request / 3 s), retries on 406 / 429 / 5xx, and falls back from arXiv to Hugging Face to arxiv-txt for metadata.
Development
See AGENTS.md. Quick version:
uv sync
uv run pytest -q # offline tests
claude plugin validate . # Claude Code manifestRoadmap
BibTeX export (the arxiv-txt parser already captures BibTeX)
More venue sources for the evidence card
License
MIT
Available Tools
2 toolsfetch_paper_details_from_arxivB
Get the Arxiv info for a list of papers.
Args:
arxiv_ids (list[str] | str): The IDs of the papers to get the Arxiv info for, e.g. ["2503.01469", "2503.01470"]
| Name | Required | Description | Default |
|---|---|---|---|
| arxiv_ids | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool fetches info but doesn't describe key behaviors like whether it's a read-only operation, error handling for invalid IDs, rate limits, or authentication needs. This is a significant gap for a tool with no annotation coverage.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is appropriately sized and front-loaded, with the main purpose stated first and parameter details following. It uses two sentences efficiently, with no wasted words, making it easy to parse quickly.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's low complexity (1 parameter) and the presence of an output schema, the description is somewhat complete but has gaps. It covers the basic purpose and parameter usage but lacks behavioral details and usage guidelines. With an output schema, it doesn't need to explain return values, but overall it's only minimally adequate.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description adds meaningful semantics beyond the input schema. The schema has 0% description coverage, but the description explains that 'arxiv_ids' can be a list or string and provides an example (e.g., ["2503.01469", "2503.01470"]), clarifying usage. With only one parameter, this compensates well for the low schema coverage.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: 'Get the Arxiv info for a list of papers.' It specifies the verb ('Get') and resource ('Arxiv info'), making it understandable. However, it doesn't explicitly differentiate from the sibling tool 'semantic_search_papers_on_huggingface', which appears to be a search tool rather than a direct fetch by ID, so it misses full sibling distinction.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides no guidance on when to use this tool versus alternatives. It doesn't mention the sibling tool or any other context for usage, such as prerequisites or scenarios where this tool is preferred over others. This leaves the agent without explicit direction on tool selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
semantic_search_papers_on_huggingfaceB
Search for papers on HuggingFace using semantic search.
Args:
query (str): The query term to search for. It will automatically determine if it should use keywords or a natural language query, so format your queries accordingly.
top_n (int): The number of papers to return. Default is 10, but you can set it to any number.
Returns:
str: A list of papers with the title, summary, ID, and upvotes.
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | ||
| top_n | No |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions that the query 'will automatically determine if it should use keywords or a natural language query,' which adds some context about the tool's behavior. However, it lacks details on rate limits, authentication needs, error handling, or what happens with invalid inputs, which are important for a search tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is appropriately sized and front-loaded, with the core purpose stated first. The Args and Returns sections are structured clearly, though the 'Returns' section could be more concise (e.g., listing fields without full sentences). Overall, it's efficient with minimal waste.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's moderate complexity (2 parameters, no annotations, but with an output schema), the description is reasonably complete. It explains the parameters and return format, and the output schema likely covers the return structure in detail. However, it could benefit from more behavioral context (e.g., search scope, limitations) to be fully comprehensive.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description adds significant meaning beyond the input schema, which has 0% description coverage. It explains that 'query' can be keywords or natural language and will be automatically interpreted, and it specifies the default and flexibility for 'top_n'. This compensates well for the schema's lack of descriptions, though it doesn't cover all possible edge cases (e.g., query length limits).
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: 'Search for papers on HuggingFace using semantic search.' This specifies the verb (search), resource (papers on HuggingFace), and method (semantic search). However, it doesn't explicitly differentiate from the sibling tool 'fetch_paper_details_from_arxiv' (which appears to fetch details rather than search), so it doesn't reach the highest score.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides no guidance on when to use this tool versus alternatives. While it mentions semantic search, it doesn't explain when to prefer this over keyword-based search or the sibling tool. There's no mention of prerequisites, limitations, or typical use cases, leaving the agent with minimal context for selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
2 tool updates
- First observed
fetch_paper_details_from_arxiv - First observed
semantic_search_papers_on_huggingface
TDQS
Scored across 2 tools
The two tools have clearly distinct purposes: one fetches details for specific Arxiv papers by ID, while the other performs semantic searches on HuggingFace. There is no overlap in functionality or ambiguity between them.
Both tools follow a consistent snake_case naming pattern with descriptive verb_noun structures (fetch_paper_details_from_arxiv and semantic_search_papers_on_huggingface). The naming is predictable and readable throughout.
With only two tools, the server feels under-scoped for a paper-related domain. It lacks basic operations like listing papers, filtering, or managing collections, which limits its utility for comprehensive paper handling tasks.
The toolset is severely incomplete for paper management. It covers fetching details and searching, but misses essential CRUD operations (e.g., saving, organizing, or annotating papers) and lacks integration between the two sources, leaving significant gaps in workflow coverage.
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