# Research Paper & DOI Lookup (Crossref)

> Verify a DOI or find papers via Crossref metadata. $0.005/call via x402.

- name: io.github.pcp183/paper-lookup
- version: 0.2.0
- connection class: unknown (unknown)
- trust: 67/100 flags: unreachable
- quality: 73/100 (new)
- owner: not claimed
- descriptor: https://api.protogrid.dev/v1/servers/io.github.pcp183%2Fpaper-lookup
- tools: https://api.protogrid.dev/v1/servers/io.github.pcp183%2Fpaper-lookup/tools

**Not classified yet.** The remote endpoints have not been probed successfully, or the listing has nothing to connect to.

## Connection (mcpServers)

```json
{
  "mcpServers": {
    "paper-lookup": {
      "type": "http",
      "url": "https://paper-lookup-production-56b0.up.railway.app/mcp"
    }
  }
}
```


## Trust

- hygiene: 100
- liveness: 0
- freshness: 100
- provenance: 90
- drivers: +repository +namespace-matches-repo +website -unreachable(4 failures) +updated-4d-ago
- Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed.

## Quality 73/100 (new)

### protocol: 75 (weight 25)

- warn `protocol.modern`: newest supported version is 2025-11-25; 2026-07-28 not supported, older versions are deprecated until 2027-07-28
- n/a `protocol.stateless`: only applies to 2026-07-28 servers
- pass `protocol.transport`: streamable HTTP
- n/a `protocol.list_ttl`: only applies to 2026-07-28 servers

### authorization: n/a (weight 15)

- n/a `auth.prm`, `auth.as_metadata`, `auth.cimd`: no remote uses OAuth
- n/a `auth.secret_in_url`: no templated URL

### tool hygiene: 71 (weight 30)

- pass `tools.descriptions`: every tool has a description
- pass `tools.description_length`: descriptions are concise
- pass `tools.schemas`: every tool has an object input schema
- fail `tools.annotations`: no tool declares readOnlyHint or destructiveHint, so clients cannot tell safe calls from risky ones
- fail `tools.directory_hints`: no tool declares all four of readOnlyHint, destructiveHint, idempotentHint and openWorldHint; missing: paper_lookup (readOnlyHint, destructiveHint, idempotentHint, openWorldHint)
- pass `tools.token_cost`: about 328 tokens to load every tool
- pass `tools.api_dump`: tools are not a one-to-one API dump

### stability: n/a (weight 15)

- n/a `stability.changes`, `stability.rug_pull`: tool history recorded for 3 of the 7 days needed

### dependencies: n/a (weight 15)

- n/a `deps.known_vulns`, `deps.mcp_sdk_version`, `deps.resolvable`: no npm or PyPI package

- tools: 1, about 328 tokens to load them all
- tool set hash: 4a25b4bd2b4a6f4765b29f932295b5a1
- badge: [![protogrid quality](https://protogrid.dev/badge/io.github.pcp183/paper-lookup.svg)](https://protogrid.dev/servers/io.github.pcp183/paper-lookup)
- Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed.

### Tool changes

_No tool definition changes recorded._

## Remotes

- https://paper-lookup-production-56b0.up.railway.app/mcp (streamable-http, auth none, reachable false, uptime30d 0.33333334)

## Packages

_none_

## Tools (1)

- `paper_lookup`: Scholarly works metadata from Crossref (150M+ records): resolve a DOI, or search by keywords, author or title with year and type filters. Returns title, authors with ORCID, journal or publisher, publication date, type, ISSN/ISBN, citation count, references count, licence and full-text links, funders. Abstracts are excluded. Use when an agent must verify a citation or DOI, find papers on a topic, or get a paper's authors, journal, date, citation count and links. Paid per call via x402 (USDC on Base).