Agent skill · software engineering · jeremylongshore
anth-local-dev-loop
Configure a local development workflow for Anthropic Claude API projects.
Why this skill is useful
Adds specific scripts and patterns for managing local development with the Anthropic Claude API that the AI wouldn't reliably generate on its own.
What it needs
Requires node, python installed locally. Requires anthropic account access. About 3k tokens when loaded. Last updated 2026-08-07. 2,604 stars on the source repository.
What this skill does
Anthropic Local Dev Loop Overview Set up a fast local development cycle for Claude API projects with environment management, request logging, cost tracking, and hot-reload. Prerequisites Completed anth-install-auth setup Node.js 18+ or Python 3.8+ .env file with ANTHROPICAPIKEY Instructions Step 1: Project Structure Step 2: Singleton Client with Request Logging Step 3: Mock Responses for Tests Step 4: Hot-Reload Dev Script Output The development loop produces a repeatable local project layout, a single configured client, mock-backed tests, and a request log that records model and token usage. A change can then be exercised with no API spend in the normal test suite or with deliberately enabled live traffic when investigating a prompt or integration behavior. Examples While editing a prompt, run the default vitest command against a saved mock response and confirm the application handles the expected text and stop reason. When a real API check is needed, set LIVEAPI=1 only for that invocation, choose the lower-cost development model, and inspect the logger for token use. If the live response changes the contract, first update the fixture and its assertions, then rerun the mock suite so later local iterations remain fast and deterministic. Environment Management Cost Control During Development Error Handling Issue Cause Solution ------- ------- ---------- Hot reload triggers duplicate requests File save causes restart Add debounce or save-on-explicit-action .env not loading Missing dotenv setup Use dotenv package or tsx --env-file=.env Mock tests pass but live fails Response shape changed Update mocks from real API responses Resources SDK Debug Logging Pricing Next Steps Apply patterns in anth-sdk-patterns for production-ready code.
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills jeremylongshore/anth-local-dev-loop