From f97a59bd42816c128aba005fe0cd3e6613e43f3c Mon Sep 17 00:00:00 2001
From: Taras Shchybovyk <taras@eigenlabs.org>
Date: Thu, 19 Mar 2026 12:55:28 -0700
Subject: [PATCH] feat(sdk): add local development environment

Adds a "local" environment entry that points all HTTP APIs at
localhost:4399, enabling end-to-end local development with a fake
EigenCloud server and an Anvil Sepolia fork instead of real infrastructure.

- LOCAL_CHAIN_ID (31337) constant for anvil
- "local" environment config reusing sepolia-dev contract addresses
- "local" included in available environments for dev builds
- KMS keys for "local" reuse sepolia dev keys (fake server skips verification)
- Environment type union in browser.ts includes "local"
---
 packages/sdk/src/browser.ts                   |  2 +-
 .../src/client/common/config/environment.ts   | 28 +++++++++++++++++--
 packages/sdk/src/client/common/utils/keys.ts  |  8 ++++++
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/packages/sdk/src/browser.ts b/packages/sdk/src/browser.ts
index b381faa9..c9a8486c 100644
--- a/packages/sdk/src/browser.ts
+++ b/packages/sdk/src/browser.ts
@@ -251,4 +251,4 @@ export { getKMSKeysForEnvironment } from "./client/common/utils/keys";
 // =============================================================================
 // Re-export common types
 // =============================================================================
-export type Environment = "sepolia" | "sepolia-dev" | "mainnet-alpha";
+export type Environment = "sepolia" | "sepolia-dev" | "mainnet-alpha" | "local";
diff --git a/packages/sdk/src/client/common/config/environment.ts b/packages/sdk/src/client/common/config/environment.ts
index 5fdfe9a6..fa03b10c 100644
--- a/packages/sdk/src/client/common/config/environment.ts
+++ b/packages/sdk/src/client/common/config/environment.ts
@@ -8,6 +8,7 @@ import { BillingEnvironmentConfig, EnvironmentConfig } from "../types";
 // Chain IDs
 export const SEPOLIA_CHAIN_ID = 11155111;
 export const MAINNET_CHAIN_ID = 1;
+export const LOCAL_CHAIN_ID = 31337; // anvil default
 
 // Common addresses across all chains
 export const CommonAddresses: Record<string, string> = {
@@ -36,6 +37,26 @@ const BILLING_ENVIRONMENTS: Record<"dev" | "prod", BillingEnvironmentConfig> = {
 
 // Chain environment configurations
 const ENVIRONMENTS: Record<string, Omit<EnvironmentConfig, "chainID">> = {
+  /**
+   * Local development environment.
+   * Points all HTTP APIs at localhost:4399 — run a fake EigenCloud API server
+   * that implements the UserAPI and BuildAPI endpoints locally.
+   *
+   * Uses the same contract addresses as sepolia-dev so that an Anvil Sepolia
+   * fork works out of the box:
+   *   anvil --fork-url https://ethereum-sepolia-rpc.publicnode.com
+   */
+  local: {
+    name: "local",
+    build: "dev",
+    appControllerAddress: "0xa86DC1C47cb2518327fB4f9A1627F51966c83B92" as Address,
+    permissionControllerAddress: ChainAddresses[SEPOLIA_CHAIN_ID].PermissionController,
+    erc7702DelegatorAddress: CommonAddresses.ERC7702Delegator,
+    kmsServerURL: "http://localhost:4399",
+    userApiServerURL: "http://localhost:4399",
+    defaultRPCURL: "http://localhost:8545",
+    usdcCreditsAddress: "0xbdA3897c3A428763B59015C64AB766c288C97376" as Address,
+  },
   "sepolia-dev": {
     name: "sepolia",
     build: "dev",
@@ -103,12 +124,13 @@ export function getEnvironmentConfig(environment: string, chainID?: bigint): Env
   }
 
   // Determine chain ID from environment if not provided
-  // Both "sepolia" and "sepolia-dev" use Sepolia chain ID
   const resolvedChainID =
     chainID ||
     (environment === "sepolia" || environment === "sepolia-dev"
       ? SEPOLIA_CHAIN_ID
-      : MAINNET_CHAIN_ID);
+      : environment === "local"
+        ? LOCAL_CHAIN_ID
+        : MAINNET_CHAIN_ID);
 
   return {
     ...env,
@@ -170,7 +192,7 @@ export function getAvailableEnvironments(): string[] {
   const buildType = getBuildType();
 
   if (buildType === "dev") {
-    return ["sepolia-dev"];
+    return ["sepolia-dev", "local"];
   }
 
   // prod build
diff --git a/packages/sdk/src/client/common/utils/keys.ts b/packages/sdk/src/client/common/utils/keys.ts
index 2d026690..368a040c 100644
--- a/packages/sdk/src/client/common/utils/keys.ts
+++ b/packages/sdk/src/client/common/utils/keys.ts
@@ -14,6 +14,14 @@ type BuildType = "dev" | "prod";
 type KeyPair = { encryption: string; signing: string };
 
 const KEYS = {
+  // Local development — reuses sepolia dev keys since the fake EigenCloud server
+  // does not perform KMS verification. These keys are not security-sensitive here.
+  local: {
+    dev: {
+      encryption: sepoliaDevEncryption,
+      signing: sepoliaDevSigning,
+    },
+  },
   "mainnet-alpha": {
     prod: {
       encryption: mainnetAlphaProdEncryption,