Supports cloning and managing source code from Git-based repositories for querying and context-efficient batch operations.
Provides capabilities to fetch and query source code directly from GitHub repositories by owner, repo, and specific Git refs.
Facilitates fetching, reading, and searching through source code for JavaScript and TypeScript packages and their dependencies.
Allows fetching, searching, and querying source code from the npm registry, enabling context-efficient analysis of Node.js dependencies.
Enables fetching and searching Python package source code from the Python Package Index (PyPI) for server-side querying and analysis.
Allows for the retrieval and exploration of Python dependency source code through PyPI and pip-compatible sources.
Supports fetching and searching source code for Rust crates from the crates.io registry.
Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@opensrc-mcpfetch the zod package and search for where parse is defined"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
opensrc-mcp
A codemode MCP server for fetching and querying dependency source code.
Why?
Traditional MCP exposes tools directly to LLMs. This server uses the codemode pattern: agents write JavaScript that executes server-side, and only results return. Benefits:
Context efficient - Large source trees stay server-side
Batch operations - One call to search/read multiple files
LLMs are better at code - More training data for JS than tool-calling
Installation
npm install -g opensrc-mcp
# or
npx opensrc-mcpOpenCode Configuration
Add to your OpenCode config (~/.config/opencode/config.json or project opencode.json):
{
"mcp": {
"opensrc": {
"type": "local",
"command": "npx",
"args": ["-y", "opensrc-mcp"]
}
}
}Tool
execute
Single tool exposing all operations. Agents write JS that runs server-side; only results return.
// Available in sandbox:
declare const opensrc: {
// Read operations
list(): Source[];
has(name: string, version?: string): boolean;
get(name: string): Source | undefined;
files(sourceName: string, glob?: string): Promise<FileEntry[]>;
tree(sourceName: string, options?: { depth?: number }): Promise<TreeNode>;
grep(pattern: string, options?: {
sources?: string[];
include?: string;
maxResults?: number;
}): Promise<GrepResult[]>;
astGrep(sourceName: string, pattern: string, options?: {
glob?: string;
lang?: string | string[];
limit?: number;
}): Promise<AstGrepMatch[]>;
read(sourceName: string, filePath: string): Promise<string>;
readMany(sourceName: string, paths: string[]): Promise<Record<string, string>>;
resolve(spec: string): Promise<ParsedSpec>;
// Mutation operations
fetch(specs: string | string[], options?: { modify?: boolean }): Promise<FetchedSource[]>;
remove(names: string[]): Promise<RemoveResult>;
clean(options?: {
packages?: boolean;
repos?: boolean;
npm?: boolean;
pypi?: boolean;
crates?: boolean;
}): Promise<RemoveResult>;
};
declare const sources: Source[]; // All fetched sources
declare const cwd: string; // Project directoryExamples:
// List all fetched sources
async () => opensrc.list()
// Fetch npm package (auto-detects version from lockfile)
async () => opensrc.fetch("zod")
// Fetch multiple packages
async () => opensrc.fetch(["zod", "drizzle-orm", "hono"])
// Fetch GitHub repo at specific ref
async () => opensrc.fetch("vercel/ai@v3.0.0")
// Fetch from other registries
async () => opensrc.fetch("pypi:requests")
async () => opensrc.fetch("crates:serde")
// Get directory tree
async () => opensrc.tree("zod", { depth: 2 })
// Find TypeScript files
async () => opensrc.files("zod", "**/*.ts")
// Text search
async () => opensrc.grep("parse", { sources: ["zod"], include: "*.ts" })
// AST search (structural pattern matching)
async () => opensrc.astGrep("zod", "function $NAME($$$ARGS)", { glob: "**/*.ts" })
// Read a specific file
async () => opensrc.read("zod", "src/index.ts")
// Read multiple files (supports globs)
async () => opensrc.readMany("zod", ["src/index.ts", "packages/*/package.json"])
// Remove a source
async () => opensrc.remove(["zod"])
// Clean all npm packages
async () => opensrc.clean({ npm: true })Package Formats
Format | Example | Description |
|
| npm (auto-detects version) |
|
| npm specific version |
|
| explicit npm |
|
| Python/PyPI |
|
| alias for pypi |
|
| Rust/crates.io |
|
| alias for crates |
|
| GitHub repo |
|
| GitHub at ref |
|
| explicit GitHub |
Storage
Sources are stored globally at ~/.local/share/opensrc/ (XDG compliant):
~/.local/share/opensrc/
├── sources.json # Index of fetched sources
├── packages/ # npm/pypi/crates packages
│ └── zod/
│ ├── src/
│ ├── package.json
│ └── ...
└── repos/ # GitHub repos
└── github.com/
└── vercel/
└── ai/Override with $OPENSRC_DIR or $XDG_DATA_HOME.
How It Works
Agent calls
executetool with JS code:async () => opensrc.fetch("zod")Code runs in sandboxed
vmcontext with injectedopensrcAPIServer fetches package via opensrc (handles registry lookup, git clone)
Only the result returns to agent context
┌─────────────────────────────────────────────────────────────┐
│ Agent Context │
├─────────────────────────────────────────────────────────────┤
│ Tool call: execute({ code: "async () => opensrc.fetch..." })│
│ ↓ │
│ Result: { success: true, source: { name: "zod", ... } } │
└─────────────────────────────────────────────────────────────┘
↕
┌─────────────────────────────────────────────────────────────┐
│ opensrc-mcp Server │
├─────────────────────────────────────────────────────────────┤
│ Sandbox executes code with injected opensrc API │
│ Full source tree stays here, never sent to agent │
└─────────────────────────────────────────────────────────────┘License
MIT
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