fix: serialize BigInt values in readContract responses

readContract returns BigInt for uint256 fields which JSON.stringify
can't handle. Convert recursively to strings before returning.

Bumps CLI to 0.1.6.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jarrodwatts

packages/agw-cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@abstract-foundation/agw-cli",
-  "version": "0.1.5",
+  "version": "0.1.6",
   "type": "module",
   "description": "Agent-first CLI for Abstract Global Wallet workflows",
   "license": "MIT",

packages/agw-cli/src/index.ts

@@ -145,7 +145,7 @@ async function main(): Promise<void> {
   program
     .name("agw-cli")
     .description("Agent-first CLI for Abstract Global Wallet workflows.")
-    .version("0.1.5")
+    .version("0.1.6")
     .showHelpAfterError();
 
   program

packages/agw-core/src/tools/write-contract.ts

@@ -4,6 +4,17 @@ import { assertToolCapability } from "./capability-guard.js";
 import { resolveToolNetworkConfig } from "./network.js";
 import type { ToolHandler } from "./types.js";
 
+function toJsonSafe(value: unknown): unknown {
+  if (typeof value === "bigint") return value.toString();
+  if (Array.isArray(value)) return value.map(toJsonSafe);
+  if (value !== null && typeof value === "object") {
+    return Object.fromEntries(
+      Object.entries(value).map(([k, v]) => [k, toJsonSafe(v)]),
+    );
+  }
+  return value;
+}
+
 function isViewOrPure(abi: Abi, functionName: string): boolean {
   const fn = abi.find(
     (item): item is AbiFunction =>
@@ -109,7 +120,7 @@ export const writeContractTool: ToolHandler = {
       } as never);
 
       return {
-        result,
+        result: toJsonSafe(result),
         accountAddress: session.accountAddress,
         chainId: session.chainId,
         contract: { address, functionName, args: args ?? [] },