Opensrc

vercel-labs/opensrc

Fetch dependency source code to give AI agents deeper implementation context. Use when the agent needs to understand how a library works internally, read source code for a package, fetch implementation details for a dependency, or explore how an npm/PyPI/crates.io package is built. Triggers include "fetch source for", "read the source of", "how does X work internally", "get the implementation of", "opensrc path", or any task requiring access to dependency source code beyond types and docs.

719 tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

2920

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/vercel-labs/opensrc --skill opensrc

What it tells the agent to use

found in the instruction text

Bash runs shell commands — read the instruction before connecting

The instruction itself

6 sections, as written by the author

Source Code Fetching with opensrc

Fetches dependency source code so agents can read implementations, not just types. Clones repositories at the correct version tag and caches them globally at ~/.opensrc/.

Core Pattern

rg "parse" $(opensrc path zod)
cat $(opensrc path zod)/src/types.ts
find $(opensrc path zod) -name "*.test.ts"

opensrc path <pkg> prints the absolute path to cached source. If not cached, it fetches automatically. Progress goes to stderr, path to stdout, so $(opensrc path ...) works in subshells.

Fetching Source Code

opensrc path zod
opensrc path pypi:requests
opensrc path crates:serde
opensrc path facebook/react

# Multiple packages at once
opensrc path zod react next
opensrc path pypi:requests pypi:flask
opensrc path crates:serde crates:tokio

# Specific versions
opensrc path [email protected]
opensrc path pypi:[email protected]
opensrc path owner/[email protected]
opensrc path owner/repo#main

Version Resolution

For npm packages, opensrc auto-detects the installed version from lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock). Use --cwd to resolve from a different project:

opensrc path zod --cwd /path/to/project

For PyPI and crates.io, explicit versions or latest are used. For repos, use @ref or #ref to pin a branch, tag, or commit.

Managing the Cache

Source is cached globally at ~/.opensrc/ (override with OPENSRC_HOME).

opensrc list                     # show all cached sources
opensrc list --json              # JSON output

opensrc remove zod               # remove a package
opensrc remove facebook/react    # remove a repo

opensrc clean                    # remove everything
opensrc clean --npm              # only npm packages
opensrc clean --pypi             # only PyPI packages
opensrc clean --crates           # only crates.io packages
opensrc clean --packages         # all packages, keep repos
opensrc clean --repos            # all repos, keep packages

When to Fetch Source

Fetch source when you need to:

Understand internal behavior that types don't reveal
Debug unexpected library behavior
Learn patterns from well-known implementations
Verify how a function handles edge cases

Don't fetch source for simple API usage questions that docs or types can answer.

How to use it

Copy the folder

Take vercel-labs/opensrc from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.