whichlib

Official3 tools

by josifb · JavaScript

Dependency picker for coding agents: recommends, compares and scores GitHub repos with a verdict.

io.github.josifb/whichlib — Model Context Protocol (MCP) Server

The MCP server io.github.josifb/whichlib is a “dependency picker for coding agents.” It recommends repositories, compares them, and scores options to produce a verdict, using the server’s description as the basis for its stated purpose.

🛠️ Key Features

Recommends GitHub repositories
Compares GitHub repositories
Scores repositories
Produces a verdict

🚀 Use Cases

Selecting dependencies for coding agents
Evaluating multiple GitHub repo options
Determining which repository to choose based on a verdict

⚡ Developer Benefits

Clear comparison and scoring workflow for GitHub repos
Output includes a verdict, supporting decision-making in agent tooling

⚠️ Limitations

Available metadata does not specify supported tools, configuration, or how scoring/verdicts are computed

Topics

ai-agentsclaude-codecursordependenciesdeveloper-toolsgithubmcpmcp-servermodel-context-protocolnpm

Captured live from the server via tools/list.

recommend_repos

Find the best open-source library for a need before adding a dependency. Give the need in plain words and get up to `limit` GitHub repositories ranked by fit = score x relevance to the need. Each result has a 0-100 score (momentum 40% (stars gained per week; without history, lifetime stars per week scaled by the npm/PyPI download trend), maintenance 25%, adoption incl. npm/PyPI weekly downloads 25%, license 10%), a tier (Strong >=75, Solid >=50, Watch >=25, Avoid <25; New for repos under 30 days old, too new to judge), a one-line verdict and the full breakdown. Use this when you do not yet have candidates; use compare_repos when you already have names. Makes 3 GitHub searches plus npm/PyPI lookups for the shortlist. Hosted: 50 free tool calls per day per user; send header X-GitHub-Token with your own GitHub token for unlimited use, or run the npm package locally (npx -y whichlib).

Parameters3

need	string	required	The need in plain words, e.g. "python pdf parser", "react state management". Name the task, not a library.
language	string	optional	GitHub language name, e.g. "TypeScript", "Python", "Rust", "C++". JavaScript also matches TypeScript repositories and the reverse; Python also matches Jupyter Notebook. Omit to search all languages.
limit	integer	optional	How many repositories to return, 1-10.

Raw schema

{
  "type": "object",
  "properties": {
    "need": {
      "type": "string",
      "minLength": 2,
      "maxLength": 200,
      "description": "The need in plain words, e.g. \"python pdf parser\", \"react state management\". Name the task, not a library."
    },
    "language": {
      "description": "GitHub language name, e.g. \"TypeScript\", \"Python\", \"Rust\", \"C++\". JavaScript also matches TypeScript repositories and the reverse; Python also matches Jupyter Notebook. Omit to search all languages.",
      "type": "string",
      "minLength": 1,
      "maxLength": 40
    },
    "limit": {
      "default": 5,
      "description": "How many repositories to return, 1-10.",
      "type": "integer",
      "minimum": 1,
      "maximum": 10
    }
  },
  "required": [
    "need"
  ],
  "$schema": "https://json-schema.org/draft/2020-12/schema"
}

compare_repos

Compare 2-10 known GitHub repositories side by side, best score first: score and tier, stars, forks, open issues, last push, license, npm/PyPI weekly downloads (only when the registry links back to the repository) and a verdict. Each result has a 0-100 score (momentum 40% (stars gained per week; without history, lifetime stars per week scaled by the npm/PyPI download trend), maintenance 25%, adoption incl. npm/PyPI weekly downloads 25%, license 10%), a tier (Strong >=75, Solid >=50, Watch >=25, Avoid <25; New for repos under 30 days old, too new to judge), a one-line verdict and the full breakdown. Use this to choose between candidates you already have (for example zod vs valibot) or to check a dependency the project already uses; use recommend_repos to find candidates. One GitHub API call per repository plus npm/PyPI lookups. A repository that does not exist is listed under notFound and the rest are still compared; the call fails only if none can be fetched, or when GitHub's rate limit is reached or the token is rejected. Hosted: 50 free tool calls per day per user; send header X-GitHub-Token with your own GitHub token for unlimited use, or run the npm package locally (npx -y whichlib).

Parameters1

repos

array

required

Repository names as owner/repo, e.g. ["colinhacks/zod", "fabian-hiller/valibot"]. Not URLs or npm/PyPI package names.

Raw schema

{
  "type": "object",
  "properties": {
    "repos": {
      "minItems": 2,
      "maxItems": 10,
      "type": "array",
      "items": {
        "type": "string",
        "minLength": 3,
        "maxLength": 140
      },
      "description": "Repository names as owner/repo, e.g. [\"colinhacks/zod\", \"fabian-hiller/valibot\"]. Not URLs or npm/PyPI package names."
    }
  },
  "required": [
    "repos"
  ],
  "$schema": "https://json-schema.org/draft/2020-12/schema"
}

trending_repos

Discover projects: the most-starred GitHub repositories created in the last day, week or month, or with period "rising" repositories of any age that gained the most stars this week (like GitHub Trending; risingRank keeps that order). Optionally one language; each scored and returned sorted by score (starsRank keeps the stars order). Each result has a 0-100 score (momentum 40% (stars gained per week; without history, lifetime stars per week scaled by the npm/PyPI download trend), maintenance 25%, adoption incl. npm/PyPI weekly downloads 25%, license 10%), a tier (Strong >=75, Solid >=50, Watch >=25, Avoid <25; New for repos under 30 days old, too new to judge), a one-line verdict and the full breakdown. Not the right tool for picking a dependency, since new repositories have little maintenance history; use recommend_repos for that. One GitHub search (rising: one download of the daily list from raw.githubusercontent.com instead), plus one npm/PyPI lookup per repository when withDownloads is true. Hosted: 50 free tool calls per day per user; send header X-GitHub-Token with your own GitHub token for unlimited use, or run the npm package locally (npx -y whichlib).

Parameters4

period	string	optional	"day", "week" or "month": repos created in the last 24 hours, 7 days or 30 days. "rising": repos of any age by stars gained this week (the top 1,000 repos per language plus new ones are tracked).
language	string	optional	GitHub language name, e.g. "TypeScript", "Python", "Rust". Matches that language only. Omit for all languages.
limit	integer	optional	How many repositories to return, 1-100.
withDownloads	boolean	optional	Also look up npm/PyPI weekly downloads for each repository. Slower: one registry lookup per repository.

Raw schema

{
  "type": "object",
  "properties": {
    "period": {
      "default": "week",
      "description": "\"day\", \"week\" or \"month\": repos created in the last 24 hours, 7 days or 30 days. \"rising\": repos of any age by stars gained this week (the top 1,000 repos per language plus new ones are tracked).",
      "type": "string",
      "enum": [
        "day",
        "week",
        "month",
        "rising"
      ]
    },
    "language": {
      "description": "GitHub language name, e.g. \"TypeScript\", \"Python\", \"Rust\". Matches that language only. Omit for all languages.",
      "type": "string",
      "minLength": 1,
      "maxLength": 40
    },
    "limit": {
      "default": 20,
      "description": "How many repositories to return, 1-100.",
      "type": "integer",
      "minimum": 1,
      "maximum": 100
    },
    "withDownloads": {
      "default": false,
      "description": "Also look up npm/PyPI weekly downloads for each repository. Slower: one registry lookup per repository.",
      "type": "boolean"
    }
  },
  "$schema": "https://json-schema.org/draft/2020-12/schema"
}

whichlib/README.md5 KBView on GitHub

whichlib

The dependency picker for coding agents. Ask which library to use and get a scored, verified answer instead of a guess.

whichlib is an MCP server with three tools. It speaks MCP 2026-07-28; older clients keep working. Every repository it returns carries a transparent 0–100 score (momentum, maintenance, adoption including npm and PyPI downloads, license), a tier, a one-line verdict and the full breakdown, so the agent can justify the pick and you can read why.

For teams (waitlist): alerts when a dependency your repos use goes stale, and rules your team's coding agents must follow when they add one. Add a 👍 to the waitlist issue; at 20 signups it gets built. whichlib itself stays free.

Install

Claude Code:

code

claude mcp add whichlib -- npx -y whichlib

Cursor, Windsurf and other MCP clients:

json

{ "mcpServers": { "whichlib": { "command": "npx", "args": ["-y", "whichlib"] } } }

Requires Node 22 or newer. No account, no API key.

Use it without installing (hosted, no Node needed):

code

claude mcp add --transport http whichlib https://whichlib.com/mcp

Limits and the web API: https://whichlib.com/docs/

Tools

Tool	Ask	You get
`recommend_repos`	`need` in plain words, optional `language`, `limit` 1–10	The best repositories for the need, ranked by fit (score × relevance), with downloads and a verdict each
`compare_repos`	`repos`: 2–10 names as `owner/repo`	The repositories side by side, best first, same breakdown
`trending_repos`	`period` day / week / month / rising, optional `language`, `limit`	Most-starred repositories created in the period, scored; `rising`: repositories of any age by stars gained this week

Example, in Claude Code: "which Python PDF parser should I use?" → MinerU, pdfplumber, pypdf with scores, weekly downloads and verdicts like "Rising fast, 26k downloads/wk, pushed 3 days ago, Apache-2.0".

Score

Part	Weight	Signal
Momentum	40%	Stars gained over 7 days (from daily star counts when available), else stars per day since creation, scaled by the npm/PyPI download trend when known (0.5–2x). Log scale.
Maintenance	25%	Days since last push, full marks to 30 days, zero at a year. Widely used repos (10k+ stars or 100k+ weekly downloads) never drop below half.
Adoption	25%	Stars, forks and npm / PyPI weekly downloads, log scale.
License	10%	Permissive 1.0, weak copyleft 0.75, strong copyleft 0.5, none 0.

Tiers: Strong ≥ 75, Solid ≥ 50, Watch ≥ 25, Avoid; repos younger than 30 days are New ("Too new to judge"), whatever their score. Archived repos are capped at 20. On a 20-need eval the top recommendation is an accepted answer 75% of the time and the top five contain one 100% of the time; the eval and its reports live in the repository.

Environment variables, all optional

GITHUB_TOKEN: raises GitHub's search limit from 10 to 30 per minute. A fine-grained token with no permissions is enough. Recommend makes three searches per call.
WHICHLIB_HISTORY=off: do not download daily star counts. By default the server keeps the last 10 days in ~/.whichlib/stars/, refreshed in the background at most every 12 hours from raw.githubusercontent.com, so momentum uses real stars gained per week for the top 1,000 repos per language and new trending repos. Nothing is sent with that download.
FRESH_REPOS_DATA_DIR: a folder of daily snapshots or star counts to use instead (see the repository's data branch).
WHICHLIB_TELEMETRY=off or DO_NOT_TRACK=1: disables anonymous call counting. What is counted: tool name, a random install id, version, platform, Node major version, the MCP protocol version of the call. Never queries, repository names or results. The aggregate numbers are public at https://whichlib-telemetry.todorovskijosif.workers.dev/stats.

Source, dashboard, data

Repository: https://github.com/josifb/whichlib (MIT). It also holds the Fresh Repos dashboard (most-starred new repositories, day / week / month, sortable, one HTML file), the nightly snapshot and enrichment jobs, the recommendation eval, and 80+ unit tests.

Development, from the whichlib/ folder of the repository:

code

npm test           # unit tests, no network
npm run mcp:smoke  # start the server over stdio and call every tool live
npm run eval       # 20-need recommendation eval (set GITHUB_TOKEN)
npm run snapshot   # today's top repos per period and language -> data/snapshots/
npm run enrich     # add npm / PyPI packages and weekly downloads to the latest snapshot
npm run score      # top repos from the latest snapshot with score and verdict
npm run pull-data  # copy snapshots from the data branch

Layout:

code

mcp/server.mjs         MCP entry (stdio)        mcp/tools.mjs       tool logic
mcp/expand.mjs         query expansion          mcp/telemetry.mjs   anonymous call counting
mcp/github-api.mjs     GitHub client + cache    mcp/data.mjs        snapshot history provider
mcp/eval/              needs, metrics, runner, inspect, results/
lib/score.js           the score, shared by browser and Node
snapshot/src/          query, normalize, github, registry, enrich, history, run, score-report, pull-data
dashboard/index.html   redirect to whichlib.com/repos (Fresh Repos)

Install

Tools (3)

recommend_reposcompare_repostrending_repos

Configuration

Environment variables

GITHUB_TOKENsecret

Optional. Raises GitHub's search limit from 10 to 30 requests per minute. A fine-grained token with no permissions is enough.

WHICHLIB_TELEMETRY

Optional. Set to "off" to disable anonymous call counting (tool name, random install id, version, platform, Node major). DO_NOT_TRACK=1 also disables it.

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "whichlib": {
      "command": "npx",
      "args": [
        "-y",
        "whichlib@0.2.3"
      ],
      "env": {
        "GITHUB_TOKEN": "<YOUR_GITHUB_TOKEN>",
        "WHICHLIB_TELEMETRY": "<YOUR_WHICHLIB_TELEMETRY>"
      }
    }
  }
}

io.github.josifb/whichlib — Model Context Protocol (MCP) Server

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

⚠️ Limitations

Topics

recommend_repos

compare_repos

trending_repos

whichlib

Install

Tools

Score

Environment variables, all optional

Source, dashboard, data

Install

Configuration

Related servers