Opensrc Agent Skill
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.
Install
one command, takes just this skill from the repositorynpx skills add https://github.com/vercel-labs/opensrc --skill opensrcWhat it tells the agent to use
found in the instruction textThe instruction itself
6 sections, as written by the authorSource 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.
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How to use it
Take vercel-labs/opensrc from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
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.