Tutorial: Package Registry

Software

Data source: npm, PyPI, crates.io, OSV.dev

Overview

Package Registry wraps npm, PyPI, crates.io, OSV.dev, handling authentication, pagination, and rate limits for you. This tutorial covers all 7 tools with working code examples you can copy and run.

Prerequisites

Sign up at https://context.gnist.ai/signup for a free API key (100 calls/day).
Choose your integration method: MCP protocol or REST API.

Connect via MCP

Add to your MCP client config (Claude Desktop, Cursor, etc.):

MCP Config

{
  "mcpServers": {
    "gnist-package-registry": {
      "url": "https://context.gnist.ai/mcp/package-registry/",
      "headers": {
        "Gnist-API-Key": "YOUR_API_KEY"
      }
    }
  }
}

Tools (7)

`get_package`

Get metadata for a package — latest version, description, license, maintainers. Args: ecosystem: Package ecosystem: 'npm', 'pypi', or 'crates'. name: Package name (e.g. 'express', 'requests', 'tokio'). Returns: Package metadata including version, description, license, homepage, repository URL, maintainers, and keywords.

Parameter	Type	Required	Description
`ecosystem`	string	required	Package ecosystem: 'npm', 'pypi', or 'crates'.
`name`	string	required	Package name (e.g. 'express', 'requests', 'tokio').

curl -X POST "https://context.gnist.ai/mcp/package-registry/" \
  -H "Content-Type: application/json" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "get_package", "arguments": {"ecosystem": "example", "name": "'express'"}}}'

import httpx

resp = httpx.post(
    "https://context.gnist.ai/mcp/package-registry/",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    json={'id': 1,
 'jsonrpc': '2.0',
 'method': 'tools/call',
 'params': {'arguments': {'ecosystem': 'example', 'name': "'express'"},
            'name': 'get_package'}},
)
print(resp.json())

`get_package_versions`

Get full release history for a package with publish timestamps. Args: ecosystem: Package ecosystem: 'npm', 'pypi', or 'crates'. name: Package name. Returns: Dictionary with count and versions list (version string + published_at timestamp).

Parameter	Type	Required	Description
`ecosystem`	string	required	Package ecosystem: 'npm', 'pypi', or 'crates'.
`name`	string	required	Package name.

curl -X POST "https://context.gnist.ai/mcp/package-registry/" \
  -H "Content-Type: application/json" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "get_package_versions", "arguments": {"ecosystem": "example", "name": "example"}}}'

import httpx

resp = httpx.post(
    "https://context.gnist.ai/mcp/package-registry/",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    json={'id': 1,
 'jsonrpc': '2.0',
 'method': 'tools/call',
 'params': {'arguments': {'ecosystem': 'example', 'name': 'example'},
            'name': 'get_package_versions'}},
)
print(resp.json())

`get_download_stats`

Get download statistics for a package. Args: ecosystem: Package ecosystem: 'npm', 'pypi', or 'crates'. name: Package name. period: Time period — 'last-week' or 'last-month' (npm and PyPI). crates.io always returns recent 90-day downloads. Returns: Dictionary with ecosystem, name, period, and download count.

Parameter	Type	Required	Description
`ecosystem`	string	required	Package ecosystem: 'npm', 'pypi', or 'crates'.
`name`	string	required	Package name.
`period`	string	optional	Time period — 'last-week' or 'last-month' (npm and PyPI). crates.io always returns recent 90-day downloads. (default: `last-week`)

curl -X POST "https://context.gnist.ai/mcp/package-registry/" \
  -H "Content-Type: application/json" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "get_download_stats", "arguments": {"ecosystem": "example", "name": "example"}}}'

import httpx

resp = httpx.post(
    "https://context.gnist.ai/mcp/package-registry/",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    json={'id': 1,
 'jsonrpc': '2.0',
 'method': 'tools/call',
 'params': {'arguments': {'ecosystem': 'example', 'name': 'example'},
            'name': 'get_download_stats'}},
)
print(resp.json())

`get_dependencies`

Get direct dependencies for a package version. Args: ecosystem: Package ecosystem: 'npm', 'pypi', or 'crates'. name: Package name. version: Specific version string. If omitted, uses the latest release. Returns: Dictionary with count and dependencies list (name, version_req, kind). For crates, kind may be 'normal', 'dev', or 'build'.

Parameter	Type	Required	Description
`ecosystem`	string	required	Package ecosystem: 'npm', 'pypi', or 'crates'.
`name`	string	required	Package name.
`version`	any	optional	Specific version string. If omitted, uses the latest release.

curl -X POST "https://context.gnist.ai/mcp/package-registry/" \
  -H "Content-Type: application/json" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "get_dependencies", "arguments": {"ecosystem": "example", "name": "example"}}}'

import httpx

resp = httpx.post(
    "https://context.gnist.ai/mcp/package-registry/",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    json={'id': 1,
 'jsonrpc': '2.0',
 'method': 'tools/call',
 'params': {'arguments': {'ecosystem': 'example', 'name': 'example'},
            'name': 'get_dependencies'}},
)
print(resp.json())

`get_vulnerabilities`

Get known vulnerabilities for a package via OSV.dev (covers npm, PyPI, crates.io). Args: ecosystem: Package ecosystem: 'npm', 'pypi', or 'crates'. name: Package name. version: Specific version to check. If omitted, returns all known vulns for the package. Returns: Dictionary with count and vulnerabilities list (OSV ID, summary, severity, aliases like CVE numbers, affected version ranges, references, published/modified dates).

Parameter	Type	Required	Description
`ecosystem`	string	required	Package ecosystem: 'npm', 'pypi', or 'crates'.
`name`	string	required	Package name.
`version`	any	optional	Specific version to check. If omitted, returns all known vulns for the package.

curl -X POST "https://context.gnist.ai/mcp/package-registry/" \
  -H "Content-Type: application/json" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "get_vulnerabilities", "arguments": {"ecosystem": "example", "name": "example"}}}'

import httpx

resp = httpx.post(
    "https://context.gnist.ai/mcp/package-registry/",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    json={'id': 1,
 'jsonrpc': '2.0',
 'method': 'tools/call',
 'params': {'arguments': {'ecosystem': 'example', 'name': 'example'},
            'name': 'get_vulnerabilities'}},
)
print(resp.json())

`search_packages`

Search for packages by keyword across npm, PyPI, or crates.io. Args: ecosystem: Package ecosystem: 'npm', 'pypi', or 'crates'. query: Search keywords (e.g. 'http client async', 'date parsing'). limit: Maximum results (1–50, default 20). Returns: Dictionary with count and packages list (name, version, description, downloads where available).

Parameter	Type	Required	Description
`ecosystem`	string	required	Package ecosystem: 'npm', 'pypi', or 'crates'.
`query`	string	required	Search keywords (e.g. 'http client async', 'date parsing').
`limit`	integer	optional	Maximum results (1–50, default 20). (default: `20`)

curl -X POST "https://context.gnist.ai/mcp/package-registry/" \
  -H "Content-Type: application/json" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "search_packages", "arguments": {"ecosystem": "example", "query": "'http"}}}'

import httpx

resp = httpx.post(
    "https://context.gnist.ai/mcp/package-registry/",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    json={'id': 1,
 'jsonrpc': '2.0',
 'method': 'tools/call',
 'params': {'arguments': {'ecosystem': 'example', 'query': "'http"},
            'name': 'search_packages'}},
)
print(resp.json())

`report_feedback`

Report a bug, feature request, or general feedback for this data source. Use this when something doesn't work as expected, when you'd like a new feature, or when you have suggestions for improvement. Args: feedback: Describe the issue or suggestion. feedback_type: One of 'bug', 'feature_request', or 'general'.

Parameter	Type	Required	Description
`feedback`	string	required
`feedback_type`	string	optional	(default: `general`)

curl -X POST "https://context.gnist.ai/mcp/package-registry/" \
  -H "Content-Type: application/json" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "report_feedback", "arguments": {"feedback": "example"}}}'

import httpx

resp = httpx.post(
    "https://context.gnist.ai/mcp/package-registry/",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    json={'id': 1,
 'jsonrpc': '2.0',
 'method': 'tools/call',
 'params': {'arguments': {'feedback': 'example'}, 'name': 'report_feedback'}},
)
print(resp.json())

Common Patterns

Search then retrieve
Use search_packages to find items, then get_package to get full details. This two-step pattern is common for exploring data before drilling down.

Pagination
Several tools support limit, offset, or page parameters. Start with small limits during development, then increase for production queries.

FAQ

What data does Package Registry provide?

Package metadata and vulnerability data from npm, PyPI, crates.io, and OSV. It exposes 7 tools: get_package, get_package_versions, get_download_stats, get_dependencies, get_vulnerabilities, search_packages, report_feedback.

What do I need to get started?

A Gnist API key (free tier: 100 calls/day). Sign up at https://context.gnist.ai/signup.

What format does the Package Registry API return?

JSON, via either MCP protocol (JSON-RPC 2.0) or REST API.

Next Steps

Interactive Playground

Try tools in your browser — no setup required.

Full Reference

Complete docs for all 7 tools.

Getting Started with Package Registry