diff --git a/ts/packages/defi-cli/src/commands/wallet.test.ts b/ts/packages/defi-cli/src/commands/wallet.test.ts
new file mode 100644
index 0000000..43250d8
--- /dev/null
+++ b/ts/packages/defi-cli/src/commands/wallet.test.ts
@@ -0,0 +1,167 @@
+// Unit tests for `defi wallet` — covers the address command (env-driven,
+// no RPC) and the no-wallet error path of balance. The happy-path
+// balance branch hits live RPC via viem and is intentionally exercised
+// by integration / Anvil-fork tests rather than mocked here.
+import { Command } from "commander";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+
+import { parseOutputMode } from "../output.js";
+import { registerWallet } from "./wallet.js";
+
+interface CapturedOutput {
+  json: string[];
+  text: string[];
+}
+
+function captureConsole(): { capture: CapturedOutput; restore: () => void } {
+  const originalLog = console.log;
+  const capture: CapturedOutput = { json: [], text: [] };
+  console.log = (msg?: unknown, ...rest: unknown[]) => {
+    const line = [msg, ...rest]
+      .map((m) => (typeof m === "string" ? m : JSON.stringify(m)))
+      .join(" ");
+    if (line.trim().startsWith("[") || line.trim().startsWith("{")) {
+      capture.json.push(line);
+    } else {
+      capture.text.push(line);
+    }
+  };
+  return {
+    capture,
+    restore: () => {
+      console.log = originalLog;
+    },
+  };
+}
+
+function buildProgram(): Command {
+  const program = new Command();
+  program.exitOverride();
+  program.option("--chain <chain>", "Target chain");
+  program.option("--json", "Output as JSON");
+  program.option("--ndjson", "Output as newline-delimited JSON");
+  program.option("--fields <fields>", "Filter output fields");
+  registerWallet(program, () =>
+    parseOutputMode(program.opts<{ json?: boolean; ndjson?: boolean; fields?: string }>()),
+  );
+  return program;
+}
+
+// Snapshot + restore the env vars resolveWalletWithSigner() consults so
+// each test runs in isolation regardless of host shell.
+const ENV_KEYS = ["DEFI_WALLET_ADDRESS", "DEFI_PRIVATE_KEY"] as const;
+let snapshot: Record<string, string | undefined> = {};
+
+beforeEach(() => {
+  snapshot = {};
+  for (const k of ENV_KEYS) {
+    snapshot[k] = process.env[k];
+    delete process.env[k];
+  }
+});
+
+afterEach(() => {
+  for (const k of ENV_KEYS) {
+    if (snapshot[k] === undefined) delete process.env[k];
+    else process.env[k] = snapshot[k];
+  }
+});
+
+describe("defi wallet address", () => {
+  it("returns null + source=none when no env vars are set", async () => {
+    const program = buildProgram();
+    const { capture, restore } = captureConsole();
+    try {
+      await program.parseAsync(["node", "defi", "--json", "wallet", "address"]);
+    } finally {
+      restore();
+    }
+    expect(capture.json.length).toBeGreaterThan(0);
+    const data = JSON.parse(capture.json.join("\n")) as { address: unknown; source: string };
+    expect(data.address).toBeNull();
+    expect(data.source).toBe("none");
+  });
+
+  it("returns the configured DEFI_WALLET_ADDRESS with source=env", async () => {
+    const fixture = "0x000000000000000000000000000000000000dEaD";
+    process.env["DEFI_WALLET_ADDRESS"] = fixture;
+
+    const program = buildProgram();
+    const { capture, restore } = captureConsole();
+    try {
+      await program.parseAsync(["node", "defi", "--json", "wallet", "address"]);
+    } finally {
+      restore();
+    }
+    const data = JSON.parse(capture.json.join("\n")) as { address: string; source: string };
+    expect(data.address).toBe(fixture);
+    expect(data.source).toBe("env");
+  });
+
+  it("derives the address from DEFI_PRIVATE_KEY with source=private_key", async () => {
+    // Hardhat's well-known account #0 — same key the defi-cli docs use
+    // for dry-run examples. Public knowledge, no funds at risk.
+    process.env["DEFI_PRIVATE_KEY"] =
+      "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80";
+
+    const program = buildProgram();
+    const { capture, restore } = captureConsole();
+    try {
+      await program.parseAsync(["node", "defi", "--json", "wallet", "address"]);
+    } finally {
+      restore();
+    }
+    const data = JSON.parse(capture.json.join("\n")) as { address: string; source: string };
+    expect(data.address.toLowerCase()).toBe(
+      "0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266",
+    );
+    expect(data.source).toBe("private_key");
+  });
+});
+
+describe("defi wallet balance", () => {
+  it("rejects with a structured error when no wallet is configured", async () => {
+    // Pre-condition: env scrubbed by beforeEach. The handler should
+    // short-circuit BEFORE touching viem / the RPC, so this test is
+    // safe to run without a network and without a chain RPC.
+    const program = buildProgram();
+    const { capture, restore } = captureConsole();
+    try {
+      await program.parseAsync([
+        "node",
+        "defi",
+        "--json",
+        "--chain",
+        "hyperevm",
+        "wallet",
+        "balance",
+      ]);
+    } finally {
+      restore();
+    }
+    expect(capture.json.length).toBeGreaterThan(0);
+    const data = JSON.parse(capture.json.join("\n")) as { error?: string };
+    expect(data.error).toBeTruthy();
+    expect(data.error).toMatch(/wallet/i);
+    expect(data.error).toMatch(/DEFI_WALLET_ADDRESS|DEFI_PRIVATE_KEY|--address/);
+  });
+
+  it("requires --chain (multi-chain balance fan-out is intentionally not supported)", async () => {
+    process.env["DEFI_WALLET_ADDRESS"] = "0x000000000000000000000000000000000000dEaD";
+    const program = buildProgram();
+    const { capture, restore } = captureConsole();
+    try {
+      // No --chain flag. requireChain() should print an error envelope
+      // and the handler must not proceed to a real RPC call.
+      await program.parseAsync(["node", "defi", "--json", "wallet", "balance"]);
+    } finally {
+      restore();
+    }
+    // Either an error envelope on the JSON channel or a stderr text
+    // explaining --chain is required is acceptable. We assert at least
+    // one channel surfaced something.
+    const everything = [...capture.json, ...capture.text].join("\n");
+    expect(everything.length).toBeGreaterThan(0);
+    expect(everything).toMatch(/chain/i);
+  });
+});