diff --git a/scripts/verify-deepseek-routing.mjs b/scripts/verify-deepseek-routing.mjs
new file mode 100755
index 00000000..fadd82c9
--- /dev/null
+++ b/scripts/verify-deepseek-routing.mjs
@@ -0,0 +1,90 @@
+#!/usr/bin/env node
+import { spawn } from 'node:child_process';
+import { existsSync } from 'node:fs';
+import { pathToFileURL } from 'node:url';
+
+export const DSH_VERSION = '0.1.5-rc.2';
+
+export const cases = [
+  { name: 'copilotkit', prompt: 'Fix a CopilotKit generative UI rendering bug. Return exactly one line: owner=copilotkit verifier=false', owner: 'copilotkit', verifier: false },
+  { name: 'systematic-debugging', prompt: 'The application build is failing and we do not know which subsystem is responsible. Return exactly one line: owner=systematic-debugging verifier=false', owner: 'systematic-debugging', verifier: false },
+  { name: 'supabase-s4', prompt: 'Change Supabase RLS tenant access rules in production. Return exactly one line: owner=supabase verifier=true', owner: 'supabase', verifier: true },
+  { name: 'mastra', prompt: 'Fix a known Mastra workflow suspend/resume bug. Return exactly one line: owner=mastra verifier=false', owner: 'mastra', verifier: false },
+  { name: 'gemini', prompt: 'Fix a known Gemini model/provider configuration bug. Return exactly one line: owner=gemini verifier=false', owner: 'gemini', verifier: false },
+  { name: 'stripe-s4', prompt: 'Fix a production Stripe payment retry that could duplicate a charge. Return exactly one line: owner=stripe verifier=true', owner: 'stripe', verifier: true },
+];
+
+export function extractFinalAnswer(output) {
+  const lines = String(output).split(/\r?\n/).map((line) => line.trim()).filter(Boolean);
+  const explicit = [...lines].reverse().find((line) => /^final answer:/i.test(line));
+  if (explicit) return explicit.replace(/^final answer:\s*/i, '').trim();
+  const structured = [...lines].reverse().find((line) => /^owner=[a-z0-9-]+\s+verifier=(true|false)$/i.test(line));
+  if (structured) return structured;
+  const nonDiagnostic = lines.filter((line) => !/^(dsh:|\[\d+\]|debug:|warning:|warn:|error:)/i.test(line));
+  return nonDiagnostic.at(-1) ?? '';
+}
+
+export function evaluateCase(probe, status, output) {
+  const answer = extractFinalAnswer(output);
+  const match = answer.match(/^owner=([a-z0-9-]+)\s+verifier=(true|false)$/i);
+  const ok = status === 0 && !!match && match[1].toLowerCase() === probe.owner && (match[2].toLowerCase() === 'true') === probe.verifier;
+  return { ok, answer };
+}
+
+export function getDshCommand() {
+  const configuredHarness = process.env.DSH_CLI_PATH;
+  if (configuredHarness && existsSync(configuredHarness)) {
+    return { command: process.execPath, args: [configuredHarness, '--profile', 'headless'] };
+  }
+  return { command: 'npx', args: ['--yes', '--package', `@deepseek-ai/dsh@${DSH_VERSION}`, 'dsh', '--profile', 'headless'] };
+}
+
+export function runProbe(probe) {
+  return new Promise((resolve) => {
+    const dsh = getDshCommand();
+    const child = spawn(dsh.command, [...dsh.args, probe.prompt], {
+      cwd: process.cwd(),
+      env: process.env,
+      stdio: ['ignore', 'pipe', 'pipe'],
+    });
+    let output = '';
+    child.stdout.on('data', (chunk) => { output += chunk; });
+    child.stderr.on('data', (chunk) => { output += chunk; });
+    let timedOut = false;
+    const timer = setTimeout(() => { timedOut = true; child.kill('SIGTERM'); }, 120000);
+    child.on('close', (status) => {
+      clearTimeout(timer);
+      resolve({ status: timedOut ? 124 : (status ?? 1), output });
+    });
+    child.on('error', (error) => {
+      clearTimeout(timer);
+      resolve({ status: 1, output: `${output}\n${error.message}` });
+    });
+  });
+}
+
+export async function runCases(probes = cases, runner = runProbe) {
+  const executions = [];
+  for (const probe of probes) {
+    const result = await runner(probe);
+    const evaluated = evaluateCase(probe, result.status, result.output);
+    executions.push({ ...probe, ...evaluated, status: result.status, output: result.output });
+  }
+  return { failed: executions.filter((item) => !item.ok).length, results: executions };
+}
+
+async function main() {
+  const { failed, results } = await runCases();
+  for (const item of results) {
+    console.log(`${item.ok ? 'PASS' : 'FAIL'} ${item.name}`);
+    if (!item.ok) {
+      console.error(`Expected owner=${item.owner} verifier=${item.verifier}; exit=${item.status}; answer=${JSON.stringify(item.answer)}`);
+    }
+  }
+  if (failed > 0) process.exitCode = 1;
+  else console.log(`DeepSeek routing certification: PASS (${results.length}/${results.length})`);
+}
+
+if (import.meta.url === pathToFileURL(process.argv[1] ?? '').href) {
+  await main();
+}
diff --git a/src/lib/deepseek/verify-deepseek-routing.test.ts b/src/lib/deepseek/verify-deepseek-routing.test.ts
new file mode 100644
index 00000000..cae89dc5
--- /dev/null
+++ b/src/lib/deepseek/verify-deepseek-routing.test.ts
@@ -0,0 +1,32 @@
+import { describe, expect, it, vi } from 'vitest';
+import { evaluateCase, runCases } from '../../../scripts/verify-deepseek-routing.mjs';
+
+describe('DeepSeek routing certification', () => {
+  it('evaluates only the final answer, not echoed prompt diagnostics', () => {
+    const probe = { name: 'copilotkit', prompt: 'prompt mentions copilotkit', owner: 'copilotkit', verifier: false };
+    const output = 'debug: prompt mentions copilotkit\ndsh: reasoning: wrong owner\nfinal answer: maps';
+    expect(evaluateCase(probe, 0, output)).toEqual({ ok: false, answer: 'maps' });
+  });
+
+  it('accepts exact owner and verifier decisions', () => {
+    const s4 = { name: 'supabase-s4', prompt: 'x', owner: 'supabase', verifier: true };
+    expect(evaluateCase(s4, 0, 'dsh: reasoning: ...\nfinal answer: owner=supabase verifier=true')).toEqual({
+      ok: true,
+      answer: 'owner=supabase verifier=true',
+    });
+  });
+
+  it('aggregates failures across probes', async () => {
+    const probes = [
+      { name: 'a', prompt: 'a', owner: 'copilotkit', verifier: false },
+      { name: 'b', prompt: 'b', owner: 'mastra', verifier: false },
+    ];
+    const runner = vi.fn(async (probe: { name: string }) =>
+      probe.name === 'a' ? { status: 0, output: 'owner=copilotkit verifier=false' } : { status: 0, output: 'owner=gemini verifier=false' },
+    );
+    const result = await runCases(probes, runner);
+    expect(runner).toHaveBeenCalledTimes(2);
+    expect(result.failed).toBe(1);
+    expect(result.results.map((item) => item.ok)).toEqual([true, false]);
+  });
+});