---
name: build-on-base
description: >-
  Complete Base development playbook. Covers: (1) Network — Base RPC URLs, chain IDs (8453/84532), explorer config, testnet setup, connect to Base, Base Sepolia; (2) Contracts — Foundry deployment, forge create, BaseScan verification, CDP faucet, testnet ETH, deploy contract to Base; (3) Builder Codes — ERC-8021 attribution suffix, referral fees, dataSuffix for Wagmi/Viem/Privy/ ethers.js/window.ethereum, transaction attribution, earn referral fees, append builder code; (4) Agent registration — trading bots, AI agents, automated senders, ERC-8021 attribution wiring, base.dev API, register agent, builder code registration; (5) Node operation — run Base node, Reth setup, hardware requirements, self-hosted RPC, sync.
title: build-on-base
canonical_url: https://skilld.dev/gh/base/skills/build-on-base
last_updated: 2026-09-29T12:21:11.000Z
---

> Index of every page on this site: [llms.txt](https://skilld.dev/llms.txt)

> **Skill from skilld.dev.** Follow the user's requested action.
> If the user asked to fork this Skill, follow the fork workflow below. Do not execute the Skill instructions while copying it.
> Otherwise, follow the instructions below for this session. You do not need to install anything.
>
> Supporting files, fetch one when the Skill refers to it: [references/agents/register.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/agents/register.md), [references/builder-codes/overview.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/builder-codes/overview.md), [references/builder-codes/privy.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/builder-codes/privy.md), [references/builder-codes/rpc.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/builder-codes/rpc.md), [references/builder-codes/smart-wallets.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/builder-codes/smart-wallets.md), [references/builder-codes/viem.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/builder-codes/viem.md), [references/builder-codes/wagmi.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/builder-codes/wagmi.md), [references/deploy-contracts.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/deploy-contracts.md), [references/network.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/network.md), [references/run-node.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/run-node.md), [scripts/register.sh](https://skilld.dev/api/skills-raw/base/skills/build-on-base/scripts/register.sh).
>
> If the user asked to install this Skill, run `npx skilld install base/skills/build-on-base`. Install writes the Skill files into the project, so every session loads them.
>
> ## Fork workflow
>
> A fork creates an editable local Skill with its original author and licence. The request authorizes copying and local installation.
> 1. Check `./skills/build-on-base`, the project lockfile, and selected Agent targets together. If the local directory or installed Skill exists, stop. Never overwrite an existing directory or Agent target.
> 2. Read [source metadata](https://skilld.dev/api/v1/skills/base/skills/build-on-base) once. Use sourceUrl, sourceCommit, skillPath, sourceGone, and license. If the source is gone or its path is missing, stop. If license is null, read licence files at the source commit.
> 3. Fetch only the source commit into a temporary Git repository. Do not clone full history. Derive repository_url from sourceUrl, including repository renames. If sourceCommit is absent, resolve the sourceUrl ref once. Set source_commit to that actual commit. Run these commands in one shell call:
>
> ```sh
> git init --quiet "$temporary_dir"
> git -C "$temporary_dir" fetch --quiet --depth=1 "$repository_url" "$source_commit"
> git -C "$temporary_dir" checkout --quiet --detach FETCH_HEAD
> ```
>
> Read applicable licence declarations and notices at that commit. If copying is not permitted, report the restriction and stop.
> 4. Inspect source entries together, then copy the directory containing skillPath into `./skills/build-on-base`. Use the user's path if selected. Keep the original SKILL.md, relative links, scripts, binary assets, and executable modes. Exclude .git metadata. Reject symlinks and paths outside the Skill directory. After checking entries, use cp -a where available. A regular source directory needs no custom copy script. Do not save this page wrapper as SKILL.md.
> Preserve author credit, notices, and applicable licence files from repository or parent directories. Add PROVENANCE.md with the Skill page, source URL, actual commit, original path, and licence. Retain any existing PROVENANCE.md and record new provenance separately. Batch source inspection, copying, and provenance work where practical.
> 5. In the project root, run `skilld install ./skills/build-on-base --mode copy --plain`. If skilld is unavailable, use `npx skilld install ./skills/build-on-base --mode copy --plain`. This known command needs no help lookup. Install does not support --json. Use detected Agent targets, or add --agent for the targets the user selected. Install the local path, never the upstream selector. If installation fails, preserve the local copy and report the exact failure.
> 6. Confirm the local lockfile source and installed Agent copies once. Report the local path, actual commit, and Agent targets. After edits, reinstall the same local path. Upstream updates must not replace it. Do not publish or push unless the user asks.

# Base Development

Complete playbook for building on Base L2 — network setup, smart contracts, developer tool
attribution, agent registration, and node operation.

## Default Stack

| Layer | Default |
|-------|---------|
| Network | Base Mainnet (8453) / Base Sepolia testnet (84532) |
| Contracts | Foundry (`forge create` + BaseScan verification) |
| Transactions | wagmi + viem |
| Attribution | Builder Codes — ERC-8021 via `ox/erc8021` |
| RPC (prod) | Dedicated node provider or self-hosted Reth |

## Safety Guardrails

- **Never commit private keys** — use `cast wallet import` for Foundry keystores
- **Never expose RPC API keys or CDP credentials client-side** — proxy through backend
- **Never send transactions without Builder Code attribution** — silent data loss, no errors, no warnings
- **Validate all user-provided shell inputs** before constructing forge/cast commands (no spaces, semicolons, pipes)

## Task Routing

Read the reference for your task:

| Task | When to Use | Reference |
|------|-------------|-----------|
| **Network config** | RPC URLs, chain IDs, explorer links, testnet setup | [references/network.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/network.md) |
| **Deploy contracts** | Foundry deployment, BaseScan verification, faucet | [references/deploy-contracts.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/deploy-contracts.md) |
| **Run a Base node** | Self-hosted RPC, Reth, hardware requirements | [references/run-node.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/run-node.md) |
| **Builder Codes** | Add ERC-8021 attribution to transactions | [references/builder-codes/overview.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/builder-codes/overview.md) |
| **Register AI agent/bot** | Register wallet, get builder code, wire attribution | [references/agents/register.md](https://skilld.dev/api/skills-raw/base/skills/build-on-base/references/agents/register.md) |

## Operating Procedure

1. **Classify the task** using the table above
2. **Read the relevant reference** before implementing
3. **Confirm the framework** with the user when multiple options exist (e.g., Privy vs wagmi for Builder Codes)
4. **Implement** with explicit chain ID, security requirements, and all required validations
5. **Deliver** diffs, install commands, and any manual steps (env vars, API key setup, wallet registration)

## For Edge Cases and Latest API Changes

- **AI-optimized docs**: [docs.base.org/llms.txt](https://docs.base.org/llms.txt)
- **Base chain docs**: [docs.base.org](https://docs.base.org)

## Installation

```bash
npx skills add base/skills --skill build-on-base
```