diff --git a/packages/spark/src/coding-tools.ts b/packages/spark/src/coding-tools.ts
index 662866a..9696411 100644
--- a/packages/spark/src/coding-tools.ts
+++ b/packages/spark/src/coding-tools.ts
@@ -1,6 +1,8 @@
 export {
   buildClaudeCommandForTest,
+  buildClaudeSmokeCommandForTest,
   buildCodexCommandForTest,
+  buildCodexSmokeCommandForTest,
   codingToolLabel,
   discoverCodingTools,
   parseClaudeEventForTest,
diff --git a/packages/spark/src/coding-tools/claude.ts b/packages/spark/src/coding-tools/claude.ts
index da03286..b13bca7 100644
--- a/packages/spark/src/coding-tools/claude.ts
+++ b/packages/spark/src/coding-tools/claude.ts
@@ -23,6 +23,10 @@ export const claudeAdapter: Adapter = {
     command: commandPath,
     args: [
       "-p",
+      "--model",
+      "haiku",
+      "--effort",
+      "low",
       "--verbose",
       "--output-format",
       "stream-json",
diff --git a/packages/spark/src/coding-tools/codex.ts b/packages/spark/src/coding-tools/codex.ts
index d2992e9..e509684 100644
--- a/packages/spark/src/coding-tools/codex.ts
+++ b/packages/spark/src/coding-tools/codex.ts
@@ -14,7 +14,14 @@ import {
   stringField,
 } from "./utils";
 
-const CODEX_MODEL_ARGS = [
+const CODEX_SMOKE_MODEL_ARGS = [
+  "--model",
+  "gpt-5.4-mini",
+  "-c",
+  'model_reasoning_effort="low"',
+] as const;
+
+const CODEX_RUN_MODEL_ARGS = [
   "--model",
   "gpt-5.5",
   "-c",
@@ -33,7 +40,7 @@ export const codexAdapter: Adapter = {
       "--json",
       "--ephemeral",
       "--skip-git-repo-check",
-      ...CODEX_MODEL_ARGS,
+      ...CODEX_SMOKE_MODEL_ARGS,
       "-s",
       "read-only",
       "-C",
@@ -50,7 +57,7 @@ export const codexAdapter: Adapter = {
       "--json",
       "--ephemeral",
       "--skip-git-repo-check",
-      ...CODEX_MODEL_ARGS,
+      ...CODEX_RUN_MODEL_ARGS,
       "-s",
       "danger-full-access",
       "--dangerously-bypass-approvals-and-sandbox",
diff --git a/packages/spark/src/coding-tools/index.ts b/packages/spark/src/coding-tools/index.ts
index ffc73f2..2ddaa16 100644
--- a/packages/spark/src/coding-tools/index.ts
+++ b/packages/spark/src/coding-tools/index.ts
@@ -100,6 +100,14 @@ export function buildClaudeCommandForTest(args: {
   return adapterFor("claude").runCommand(args);
 }
 
+export function buildClaudeSmokeCommandForTest(args: {
+  readonly commandPath: string;
+  readonly cwd: string;
+  readonly prompt: string;
+}): CommandSpec {
+  return adapterFor("claude").smokeCommand(args);
+}
+
 export function buildCodexCommandForTest(args: {
   readonly commandPath: string;
   readonly cwd: string;
@@ -109,6 +117,14 @@ export function buildCodexCommandForTest(args: {
   return adapterFor("codex").runCommand(args);
 }
 
+export function buildCodexSmokeCommandForTest(args: {
+  readonly commandPath: string;
+  readonly cwd: string;
+  readonly prompt: string;
+}): CommandSpec {
+  return adapterFor("codex").smokeCommand(args);
+}
+
 export function parseClaudeEventForTest(
   value: unknown,
   cwd: string,
diff --git a/packages/spark/test/coding-tools.test.ts b/packages/spark/test/coding-tools.test.ts
index 87af9e3..30e1ded 100644
--- a/packages/spark/test/coding-tools.test.ts
+++ b/packages/spark/test/coding-tools.test.ts
@@ -2,7 +2,9 @@ import { describe, expect, it } from "vitest";
 
 import {
   buildClaudeCommandForTest,
+  buildClaudeSmokeCommandForTest,
   buildCodexCommandForTest,
+  buildCodexSmokeCommandForTest,
   parseClaudeEventForTest,
   parseClaudeEventsForTest,
   parseClaudeStatusForTest,
@@ -115,6 +117,25 @@ describe("coding tool command construction", () => {
     expect(spec.stdin).toBe("prompt");
   });
 
+  it("builds low-cost Claude Code smoke command", () => {
+    const spec = buildClaudeSmokeCommandForTest({
+      commandPath: "/bin/claude",
+      cwd: CWD,
+      prompt: "prompt",
+    });
+
+    expect(spec.command).toBe("/bin/claude");
+    expect(spec.args).toContain("--model");
+    expect(spec.args).toContain("haiku");
+    expect(spec.args).toContain("--effort");
+    expect(spec.args).toContain("low");
+    expect(spec.args).toContain("--tools");
+    expect(spec.args).toContain("");
+    expect(spec.args).not.toContain("bypassPermissions");
+    expect(spec.args).not.toContain("--dangerously-skip-permissions");
+    expect(spec.stdin).toBe("prompt");
+  });
+
   it("builds autonomous Codex command", () => {
     const spec = buildCodexCommandForTest({
       commandPath: "/bin/codex",
@@ -134,6 +155,27 @@ describe("coding tool command construction", () => {
     expect(spec.args.at(-1)).toBe("-");
     expect(spec.stdin).toBe("prompt");
   });
+
+  it("builds low-cost Codex smoke command", () => {
+    const spec = buildCodexSmokeCommandForTest({
+      commandPath: "/bin/codex",
+      cwd: CWD,
+      prompt: "prompt",
+    });
+
+    expect(spec.command).toBe("/bin/codex");
+    expect(spec.args).toContain("--json");
+    expect(spec.args).toContain("--model");
+    expect(spec.args).toContain("gpt-5.4-mini");
+    expect(spec.args).toContain('model_reasoning_effort="low"');
+    expect(spec.args).toContain("read-only");
+    expect(spec.args).not.toContain("danger-full-access");
+    expect(spec.args).not.toContain(
+      "--dangerously-bypass-approvals-and-sandbox",
+    );
+    expect(spec.args.at(-1)).toBe("-");
+    expect(spec.stdin).toBe("prompt");
+  });
 });
 
 describe("coding tool event normalization", () => {