langchain-toolstem v0.1.3 ships Finance and SEC EDGAR tools with per-call USDC payments
u/Toolstem published `langchain-toolstem` v0.1.3 to npm, a LangChain helper package wrapping Finance equities and SEC EDGAR MCP servers with built-in x402 micropayment support, charging per-call USDC fees settled on Base mainnet.
Score breakdown
The package demonstrates a working per-call USDC micropayment model for LangChain agent tool consumption, with a confirmed live payment, offering a concrete alternative to subscription pricing for tools that vary widely in compute cost.
- 01langchain-toolstem v0.1.3 published to npm with provenance; Python package v0.1.0 available via `pip install langchain-toolstem`.
- 02Wraps two MCP servers — Finance equities and SEC EDGAR — as native LangChain tools.
- 03Uses x402 micropayment protocol: payments auto-signed on HTTP 402 responses, settled in USDC on Base mainnet.
u/Toolstem published `langchain-toolstem` v0.1.3 to npm and v0.1.0 to PyPI, a helper package that wraps two MCP servers — Finance equities and SEC EDGAR data — as native LangChain tools. The key design choice is an x402 micropayment layer integrated directly into the HTTP fetch function: a `createX402Fetch` call (TypeScript) or `create_x402_httpx_client` (Python) is initialized with a private key and an optional `maxPaymentUsd` per-call safety cap, and it automatically signs USDC payments whenever a server returns an HTTP 402 response. All payments settle on Base mainnet.
Tool names and schemas are discovered live via MCP `tools/list` on startup rather than being hardcoded.
The package exposes three exports: `createFinanceTools` (providing `get_stock_snapshot`, `get_company_metrics`, and `compare_companies`), `createSecTools` (five tools ranging from a simple filings summary at `$0.005/call` up to `compare_disclosure_signals` — which cross-references insider trades, 13F institutional moves, and 8-K events — at `$0.50/call`), and `createX402Proxy`, a convenience wrapper that spawns a local reverse proxy at `localhost:4021` for environments requiring a plain `http://` URL. Tool names and schemas are discovered live via MCP `tools/list` on startup rather than being hardcoded.
The author frames the per-call pricing model as a deliberate alternative to subscriptions, arguing that the tools vary so widely in compute cost — a ticker snapshot versus a multi-signal SEC disclosure digest touching dozens of EDGAR filings — that flat pricing would misalign cost attribution. The post reports one confirmed external paid call on June 3, and frames the project as an ongoing experiment in whether per-call micropayment economics are viable for real agent workloads. A walletless demo using cached AAPL/MSFT/GOOGL data is available at toolstem.com/playground.
Key facts
- 01langchain-toolstem v0.1.3 published to npm with provenance; Python package v0.1.0 available via `pip install langchain-toolstem`.
- 02Wraps two MCP servers — Finance equities and SEC EDGAR — as native LangChain tools.
- 03Uses x402 micropayment protocol: payments auto-signed on HTTP 402 responses, settled in USDC on Base mainnet.
- 04Finance tools cost $0.01 USDC per call; SEC tools range from $0.005 to $0.50 per call depending on complexity.
- 05Three exports: `createFinanceTools`, `createSecTools`, and `createX402Proxy` (local reverse proxy at localhost:4021).
- 06Tool names and schemas are discovered live via MCP `tools/list` on startup — nothing hardcoded.
- 07One confirmed external paid call recorded on June 3, 2026.
Topics
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