Back to blog
Package guide
May 21, 20267 min readPackages

Which Leash npm package should you use?

Choose between @leashmarket/sdk, CLI, MCP, buyer-kit, seller-kit, core, registry-utils, schemas, runner, and testing packages.

Why it matters

Leash is a system, not one package. Picking the right package first keeps the integration small and understandable.

Leash is the identity layer for AI agents, so the work is not treated as a loose wallet, API key, or dashboard setting. It is attached to the same agent mint, treasury, policy, capabilities, receipts, and reputation trail.

How Leash handles it

The packages share schemas and identity primitives but target different runtimes: apps, CLI, MCP hosts, sellers, buyers, protocol helpers, and tests.

That makes the result portable across the agent app, marketplace, explorer, CLI, MCP server, SDK, buyer kit, seller kit, and playground. The surface can change, but the identity and proof trail stay the same.

Implementation checklist

Start with the surface closest to your job: SDK for app code, MCP for AI agents, CLI for terminal ops, seller-kit for paid APIs, buyer-kit for autonomous callers, and schemas/core for low-level protocol work.

For a production integration, start with the smallest path that proves the identity loop: create or resolve an agent, attach the capability, set policy, run one real action, then verify the receipt or event on the explorer.

Install the most common packages

bash
npm install @leashmarket/sdk
npm install @leashmarket/buyer-kit @leashmarket/seller-kit
npm install -g @leashmarket/cli
npx -y @leashmarket/mcp

FAQ

Which package creates agents?

Use the CLI or MCP for local provisioning workflows. The SDK focuses on public API reads and remote control of existing agents.

Which package should a paid API use?

Use seller-kit for x402 middleware and earn receipts, with SDK identity metadata where useful.

Building with Leash?

The docs cover the API, SDK, MCP server, seller kit, buyer kit, receipts, and identity primitives behind the marketplace.

Read docs