diff --git a/packages/iios-service/src/capability/capability.certification.spec.ts b/packages/iios-service/src/capability/capability.certification.spec.ts
new file mode 100644
index 0000000..b515bfa
--- /dev/null
+++ b/packages/iios-service/src/capability/capability.certification.spec.ts
@@ -0,0 +1,27 @@
+import { describe, it, expect } from 'vitest';
+import type { CapabilityProvider, CapabilityRequest, ProviderResult } from '@insignia/iios-contracts';
+import { certifyProvider } from './capability.certification';
+import { SandboxProvider } from './sandbox.provider';
+
+describe('adapter certification checklist (P9)', () => {
+  it('SandboxProvider passes certification', async () => {
+    const report = await certifyProvider(new SandboxProvider(['WEBHOOK']));
+    expect(report.passed).toBe(true);
+    expect(report.checks.every((c) => c.ok)).toBe(true);
+  });
+
+  it('a broken provider fails with the specific failing checks', async () => {
+    const broken: CapabilityProvider = {
+      name: 'broken',
+      channelTypes: [], // no declared channels
+      capabilities: { canSend: false },
+      async send(_req: CapabilityRequest): Promise<ProviderResult> {
+        throw new Error('kaboom'); // throws instead of returning FAILED
+      },
+    };
+    const report = await certifyProvider(broken);
+    expect(report.passed).toBe(false);
+    expect(report.checks.find((c) => c.name === 'declares-capabilities')?.ok).toBe(false);
+    expect(report.checks.find((c) => c.name === 'returns-providerRef-and-outcome')?.ok).toBe(false);
+  });
+});
diff --git a/packages/iios-service/src/capability/capability.certification.ts b/packages/iios-service/src/capability/capability.certification.ts
new file mode 100644
index 0000000..47ec1fa
--- /dev/null
+++ b/packages/iios-service/src/capability/capability.certification.ts
@@ -0,0 +1,67 @@
+import type { CapabilityProvider, CapabilityRequest } from '@insignia/iios-contracts';
+
+export interface CertificationCheck {
+  name: string;
+  ok: boolean;
+  detail?: string;
+}
+export interface CertificationReport {
+  provider: string;
+  passed: boolean;
+  checks: CertificationCheck[];
+}
+
+/**
+ * The P9 adapter-certification checklist as runnable code. Before a provider is
+ * allowed to back a channel it must pass these — mirroring the critics' adapter
+ * doctrine: declare explicit capabilities, ack/return a provider ref, be
+ * idempotent/repeatable, tolerate edge payloads, and surface transport errors as
+ * FAILED rather than throwing (never swallow, never crash the egress path).
+ */
+export async function certifyProvider(provider: CapabilityProvider): Promise<CertificationReport> {
+  const checks: CertificationCheck[] = [];
+  const req = (over: Partial<CapabilityRequest> = {}): CapabilityRequest => ({
+    capability: 'channel.send',
+    channelType: provider.channelTypes[0] ?? 'WEBHOOK',
+    target: 'cert@test',
+    payload: { text: 'certification probe' },
+    idempotencyKey: 'cert-1',
+    ...over,
+  });
+
+  // 1. Declares explicit capabilities.
+  checks.push({
+    name: 'declares-capabilities',
+    ok: provider.channelTypes.length > 0 && provider.capabilities.canSend === true,
+    detail: `channels=${provider.channelTypes.join(',')} canSend=${provider.capabilities.canSend}`,
+  });
+
+  // 2. Returns a providerRef + a recognized outcome (never throws on a normal send).
+  let normalOk = false;
+  try {
+    const r = await provider.send(req());
+    normalOk = !!r.providerRef && ['SENT', 'BLOCKED', 'FAILED', 'RATE_LIMITED'].includes(r.outcome);
+    checks.push({ name: 'returns-providerRef-and-outcome', ok: normalOk, detail: `ref=${r.providerRef} outcome=${r.outcome}` });
+  } catch (e) {
+    checks.push({ name: 'returns-providerRef-and-outcome', ok: false, detail: `threw: ${(e as Error).message}` });
+  }
+
+  // 3. Idempotent/repeatable — same request twice succeeds both times, no throw.
+  try {
+    const a = await provider.send(req({ idempotencyKey: 'cert-idem' }));
+    const b = await provider.send(req({ idempotencyKey: 'cert-idem' }));
+    checks.push({ name: 'repeatable', ok: !!a.providerRef && !!b.providerRef, detail: 'two sends returned refs' });
+  } catch (e) {
+    checks.push({ name: 'repeatable', ok: false, detail: `threw: ${(e as Error).message}` });
+  }
+
+  // 4. Tolerates an empty payload (surfaces channel quirks, never crashes).
+  try {
+    const r = await provider.send(req({ payload: {}, idempotencyKey: 'cert-empty' }));
+    checks.push({ name: 'tolerates-empty-payload', ok: !!r.providerRef, detail: `outcome=${r.outcome}` });
+  } catch (e) {
+    checks.push({ name: 'tolerates-empty-payload', ok: false, detail: `threw: ${(e as Error).message}` });
+  }
+
+  return { provider: provider.name, passed: checks.every((c) => c.ok), checks };
+}