nonameuserd/paybond-kit

**Your AI agent shouldn't accidentally spend $20,000.**
An unsupervised agent that can book travel, call paid APIs, or buy compute can also loop through “approved” tool calls until the budget is gone — each charge succeeds, and nothing proves the work was delivered. Per-transaction caps alone do not stop that.
**@paybond/kit** is the TypeScript SDK for delegated agent spend controls: authorize against a bounded budget and policy *before* a paid tool runs, then release or refund only after signed completion evidence. Wrap three lines around any paid tool call — authorize → execute → verify. Keep your runtime. Keep your payment rails (prefer Stripe Connect / x402; Stripe ACH Direct Debit and USDC-on-Base are also available). You get spend authorization, evidence-gated settlement, refunds, disputes, and a portable signed receipt — without building your own proof-gated release middleware.
Under the hood, Kit opens hosted Gateway sessions, verifies capability tokens, signs intent and evidence payloads, and can read tenant-scoped Signal, fraud, ledger, protocol, and A2A data, with adapters for common agent runtimes.
Docs · TypeScript quickstart · Support matrix · Free sandbox signup · Python package
When to use Paybond
Reach for Paybond Kit whenever an AI agent can move money and you need spend that stays inside a budget — not just token metering: agentic payments and commerce, tool-call spend limits, outcome evidence before release, and audit-ready records — across OpenAI, Gemini, Claude/Anthropic, Vercel AI SDK, LangGraph, MCP hosts, and custom runtimes, settling through the payment rails your tenant already uses.
- **Use Paybond Kit** when spend needs authorization against a bounded budget, proof-gated release/refund/dispute handling, or audit-ready receipts.
- **Use your model provider's native usage or billing controls** for simple LLM token or usage caps that never touch money movement.
Start here (sandbox in ~60 seconds)
No account and no API key — rehearse the full authorize → execute → evidence loop locally, then open the trace dashboard:
paybond dev trace renders the middleware timeline at http://127.0.0.1:9477.
To try the same flow against the real hosted sandbox Gateway, first create a free Free Developer workspace if you do not already have a Paybond account (no card required), then:
paybond login opens a browser device-approval step; the workspace owner (you, right after signup) approves it and the CLI writes a sandbox PAYBOND_API_KEY to .env.local.
Launch the tenant-bound MCP server for MCP hosts (after paybond login):
For coding agents and LLMs, the full discovery guide lives at , and coding-agent setup ships a clean Markdown mirror at .
Install
@paybond/kit is an ESM-only package for Node.js runtimes. Use import from a Node ESM / NodeNext project or a compatible bundler.
Optional framework integrations
The core package is enough for Harbor sessions, spend guards, policy files, and paybond agent sandbox smoke. Install optional peers only when you import a framework subpath:
| Subpath | Peer dependency |
| --- | --- |
| @paybond/kit/vercel-ai | ai |
| @paybond/kit/openai-agents | @openai/agents |
| @paybond/kit/langgraph | @langchain/core, @langchain/langgraph |
| @paybond/kit/claude-agents | @anthropic-ai/claude-agent-sdk |
| @paybond/kit/google-adk | @google/adk |
| @paybond/kit/mastra | @mastra/core |
| @paybond/kit/cloudflare-agents | agents, ai |
| @paybond/kit/mcp, @paybond/kit/agent, @paybond/kit/policy | none — no extra peers required |
Thin npm wrappers (@paybond/vercel-ai, @paybond/langgraph, @paybond/openai-agents, @paybond/claude-agents, @paybond/google-adk, @paybond/mastra, @paybond/cloudflare-agents, @paybond/agent, @paybond/mcp) re-export the same subpaths for npm discoverability — install whichever matches your framework instead of the whole peer list above.