librarian
Multi-repository codebase exploration. Research library internals, find code patterns, understand architecture, compare implementations across GitHub/npm/PyPI/crates. Use when needing deep understanding of how libraries work, finding implementations across open source, or exploring remote repository structure.
Installation
Follow the repository instructions for this skill and your agent. Review the files and dependencies before adding it to your workflow.
View source ↗GuidesSkill instructions
Librarian Skill
Deep codebase exploration across remote repositories.
How to Use This Skill
Reference Structure
| File | Purpose | When to Read |
|---|---|---|
tool-routing.md |
Tool selection decision trees | Always read first |
opensrc-api.md |
API reference, types | Writing opensrc code |
opensrc-examples.md |
JavaScript patterns, workflows | Implementation examples |
linking.md |
GitHub URL patterns | Formatting responses |
diagrams.md |
Mermaid patterns | Visualizing architecture |
Reading Order
-
Start with
tool-routing.md→ choose tool strategy -
If using opensrc:
- Read
opensrc-api.mdfor API details - Read
opensrc-examples.mdfor patterns
- Read
-
Before responding:
linking.md+diagrams.mdfor output formatting
Tool Arsenal
| Tool | Best For | Limitations |
|---|---|---|
| grep_app | Find patterns across ALL public GitHub | Literal search only |
| context7 | Library docs, API examples, usage | Known libraries only |
| opensrc | Fetch full source for deep exploration | Must fetch before read |
Quick Decision Trees
"How does X work?"
Known library?
├─ Yes → context7.resolve-library-id → context7.query-docs
│ └─ Need internals? → opensrc.fetch → read source
└─ No → grep_app search → opensrc.fetch top result
"Find pattern X"
Specific repo?
├─ Yes → opensrc.fetch → opensrc.grep → read matches
└─ No → grep_app (broad) → opensrc.fetch interesting repos
"Explore repo structure"
1. opensrc.fetch(target)
2. opensrc.tree(source.name) → quick overview
3. opensrc.files(source.name, "**/*.ts") → detailed listing
4. Read: README, package.json, src/index.*
5. Create architecture diagram (see diagrams.md)
"Compare X vs Y"
1. opensrc.fetch(["X", "Y"])
2. Use source.name from results for subsequent calls
3. opensrc.grep(pattern, { sources: [nameX, nameY] })
4. Read comparable files, synthesize differences
Critical: Source Naming Convention
After fetching, always use source.name for subsequent calls:
const [{ source }] = await opensrc.fetch("vercel/ai");
const files = await opensrc.files(source.name, "**/*.ts");
| Type | Fetch Spec | Source Name |
|---|---|---|
| npm | "zod" |
"zod" |
| npm scoped | "@tanstack/react-query" |
"@tanstack/react-query" |
| pypi | "pypi:requests" |
"requests" |
| crates | "crates:serde" |
"serde" |
| GitHub | "vercel/ai" |
"github.com/vercel/ai" |
| GitLab | "gitlab:org/repo" |
"gitlab.com/org/repo" |
When NOT to Use opensrc
| Scenario | Use Instead |
|---|---|
| Simple library API questions | context7 |
| Finding examples across many repos | grep_app |
| Very large monorepos (>10GB) | Clone locally |
| Private repositories | Direct access |
Output Guidelines
- Comprehensive final message - only last message returns to main agent
- Parallel tool calls - maximize efficiency
-
Link every file reference - see
linking.md -
Diagram complex relationships - see
diagrams.md - Never mention tool names - say "I'll search" not "I'll use opensrc"
References
Examples
Read the usage examples in the source repository.
View source ↗Source history
- Indexed on
- 2026-01-20
- Index updated
- 2026-01-28
- Branch
- main
Index and sync dates describe this directory. View the source repository for code history.
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