Agent skill · software engineering · jeremylongshore
alchemy-local-dev-loop
Establish a deterministic local EVM development loop with pinned forks, synthetic fixtures, and bounded Alchemy usage. Use when adding local chain tests or repairing flaky fork-based development. Trigger with "Alchemy local dev", "Hardhat fork with Alchemy", or "pin a mainnet fork".
Why this skill is useful
Adds executable scripts for setting up a local Web3 development environment with Alchemy and Hardhat, which are not commonly found in public documentation.
What it needs
Requires node installed locally. Requires alchemy account access. About 3k tokens when loaded. Last updated 2026-08-07. 2,604 stars on the source repository.
What this skill does
Alchemy Deterministic Local Development Loop Overview Establish a deterministic local EVM development loop with pinned forks, synthetic fixtures, and bounded Alchemy usage. This workflow produces a reviewable artifact and negative-path evidence before any live side effect. Prerequisites Current first-party Alchemy documentation for the selected product, chain, feature, client, authentication method, limit, and lifecycle. Named product, application, security, data/privacy, budget, release, and operations owners appropriate to the requested scope. Synthetic or approved non-production fixtures, a credential canary, explicit success criteria, and a tested rollback boundary. Current Contract A remote mainnet fork is reproducible only when the chain, block number, dependency versions, and fixture state are pinned. It still consumes account-level throughput and can diverge when historical access, method support, or upstream state is unavailable. Alchemy Sandbox is a separate simulation option and must be evaluated against the required test semantics. Authentication Use a development-only app key from local secret injection. Never copy a production key or deployer private key into .env, task output, shell history, fixtures, or committed fork URLs. Instructions 1. Inventory the project's current Hardhat, Foundry, Anvil, or other EVM test runner and preserve its existing commands. 2. Confirm the target chain and historical method support, then select and record a stable fork block with the business reason for changing it. 3. Inject a development Alchemy endpoint through the established local secret mechanism and ensure configuration fails clearly when it is absent. 4. Use synthetic accounts and deterministic impersonation or funded fixtures; never import a real user or production signer. 5. Run the smallest fork test, a clean-room rerun, and an offline/unit fallback; record request volume and wall time without claiming a universal benchmark. 6. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills jeremylongshore/alchemy-local-dev-loop--5109d1