diff --git a/.changeset/signed-requests-preflight-fix.md b/.changeset/signed-requests-preflight-fix.md
new file mode 100644
index 000000000..98fc1a715
--- /dev/null
+++ b/.changeset/signed-requests-preflight-fix.md
@@ -0,0 +1,34 @@
+---
+'@adcp/sdk': patch
+---
+
+Unblock 3.1 `signed-requests` adopters. Two coupled fixes; the runner-side fix alone leaves adopters stuck on the boot guard, and vice versa (per #2237 triage).
+
+**1. Pre-flight `resolveStoryboardsForCapabilities` (`compliance.ts`).**
+`resolveStoryboardsForCapabilities` was throwing `unknown_specialism` on the
+deprecated `signed-requests` claim because the bundle lives under
+`universal/signed-requests.yaml`, not `specialisms/signed-requests/`. That
+blocked every other storyboard from running and prevented the
+`signed_requests_specialism_deprecated` notice (#2082) from ever firing.
+
+Adds `DEPRECATED_SPECIALISM_UNIVERSAL_ALIASES` mapping the deprecated
+specialism enum value to its universal bundle base name. When the deprecated
+alias is declared AND the universal bundle is present in the cache,
+resolution continues silently (the universal storyboard is pushed
+unconditionally and the deprecation notice fires from runner.ts).
+Otherwise the throw is preserved — unknown specialism without a universal
+fallback is still a configuration error.
+
+**2. Boot guard `createAdcpServer` (`create-adcp-server.ts`).**
+The previous guard required the deprecated `signed-requests` specialism claim
+whenever `signedRequests` was configured, contradicting the universal
+storyboard's "drop the now-redundant specialism claim and rely solely on
+`request_signing.supported: true`" guidance. Widens the guard to accept
+either discovery surface: the canonical 3.1+ form
+(`capabilities.request_signing.supported: true`, no deprecated claim) or
+the back-compat form (`specialisms: ['signed-requests']`). Still rejects
+the "config present, nothing advertised" case so buyers can't be left
+unable to discover the signing requirement. JSDoc on `SignedRequestsConfig`
+updated to document both paths.
+
+Closes #2237.
diff --git a/src/lib/server/create-adcp-server.ts b/src/lib/server/create-adcp-server.ts
index 386f756ff..6615034fd 100644
--- a/src/lib/server/create-adcp-server.ts
+++ b/src/lib/server/create-adcp-server.ts
@@ -1080,11 +1080,26 @@ export interface AdcpCapabilitiesOverrides {
  * mounts it as the transport-layer `preTransport` hook, so every inbound MCP
  * request passes the verifier before reaching the JSON-RPC router.
  *
- * A seller that declares the `signed-requests` specialism in
- * `capabilities.specialisms` MUST provide this config, and vice-versa — both
- * together or neither. `createAdcpServer` throws at construction time when
- * only one is set, closing the footgun where claiming the specialism
- * accepts unsigned mutating traffic.
+ * A seller wiring this config MUST also publish a buyer-visible discovery
+ * surface in `capabilities`, one of:
+ *
+ * - **3.1+ canonical (recommended):** set
+ *   `capabilities.request_signing.supported: true`. Buyers learn the agent
+ *   verifies signatures from `get_adcp_capabilities`; no deprecated specialism
+ *   claim required. The universal `signed_requests` storyboard grades on this
+ *   signal alone.
+ * - **Back-compat:** add `'signed-requests'` to `capabilities.specialisms`.
+ *   The 3.0-era enum value is preserved through the AdCP 4.0 deprecation cycle
+ *   (adcp#3075); when this path is taken the runner emits
+ *   `signed_requests_specialism_deprecated` (adcp-client#2082, adcp#4796).
+ *
+ * `createAdcpServer` throws at construction time when `signedRequests` is set
+ * but neither discovery surface is declared, closing the footgun where the
+ * verifier silently rejects every signed request from buyers who never learned
+ * to sign. The inverse (specialism or capability declared without a
+ * `signedRequests` config) is logged loudly but not thrown — legacy servers
+ * that hand-build the middleware via `serve({ preTransport })` stay
+ * conformant.
  *
  * `jwks`, `replayStore`, and `revocationStore` should be hoisted outside
  * the agent factory so a single verifier instance serves every request —
@@ -3645,26 +3660,39 @@ export function createAdcpServer<TAccount = unknown>(config: AdcpServerConfig<TA
     }
   }
 
-  // Enforce lock-step between the `signed-requests` specialism claim and the
-  // verifier config for the auto-wiring path. When `signedRequests` is set
-  // but the specialism isn't declared, buyers can't discover the signing
-  // requirement from `get_adcp_capabilities` — they won't sign, the
-  // verifier rejects every mutating call, and the agent is dead on arrival.
-  // That's unambiguously wrong, so we throw.
+  // Enforce that the verifier config has a buyer-visible discovery surface.
+  // When `signedRequests` is set but neither the deprecated `signed-requests`
+  // specialism claim NOR `capabilities.request_signing.supported: true` is
+  // declared, buyers can't discover the signing requirement from
+  // `get_adcp_capabilities` — they won't sign, the verifier rejects every
+  // mutating call, and the agent is dead on arrival. Two discovery surfaces
+  // are accepted:
+  //
+  // - **3.1+ canonical (recommended):** `capabilities.request_signing.supported: true`.
+  //   The universal signed_requests storyboard runs on this signal alone and
+  //   the runner emits `request_signing.required` notices for buyers.
+  // - **Back-compat:** `specialisms: ['signed-requests']`. The 3.0-era enum
+  //   is preserved through the AdCP 4.0 deprecation cycle (adcp#3075). The
+  //   runner emits `signed_requests_specialism_deprecated` notice when this
+  //   path is taken (adcp-client#2082, adcp#4796).
   //
-  // The opposite direction — claiming the specialism without a
-  // `signedRequests` config — is only wrong when the agent also doesn't
-  // wire a verifier via `serve({ preTransport })`. Legacy servers that
-  // hand-build the middleware fall into this case and are still conformant.
-  // We log a loud error so operators notice (matching the idempotency
-  // guardrail precedent) but don't throw, leaving the manual path working.
+  // The opposite direction — advertising signing without a `signedRequests`
+  // config — is only wrong when the agent also doesn't wire a verifier via
+  // `serve({ preTransport })`. Legacy servers that hand-build the middleware
+  // fall into this case and are still conformant. We log a loud error so
+  // operators notice (matching the idempotency guardrail precedent) but
+  // don't throw, leaving the manual path working.
   const specialismsClaimed = capConfig?.specialisms ?? [];
   const claimsSignedRequests = specialismsClaimed.includes('signed-requests');
-  if (signedRequests && !claimsSignedRequests) {
+  const declaresRequestSigningCapability = capConfig?.request_signing?.supported === true;
+  if (signedRequests && !claimsSignedRequests && !declaresRequestSigningCapability) {
     throw new Error(
-      'createAdcpServer: `signedRequests` is configured but `capabilities.specialisms` does not include "signed-requests". ' +
-        'Add "signed-requests" to the specialisms list — buyers discover the signing requirement from get_adcp_capabilities, ' +
-        "and omitting the claim means they won't sign their requests."
+      'createAdcpServer: `signedRequests` is configured but neither ' +
+        '`capabilities.request_signing.supported: true` nor `capabilities.specialisms: ["signed-requests"]` is declared. ' +
+        'Buyers discover the signing requirement from get_adcp_capabilities — ' +
+        'set `capabilities.request_signing = { supported: true, ... }` (canonical 3.1+ form, recommended) ' +
+        'or claim the deprecated `signed-requests` specialism (back-compat). ' +
+        "Omitting both surfaces means buyers won't sign their requests."
     );
   }
   if (claimsSignedRequests && !signedRequests) {
diff --git a/src/lib/testing/storyboard/compliance.ts b/src/lib/testing/storyboard/compliance.ts
index 483efa241..a353cd334 100644
--- a/src/lib/testing/storyboard/compliance.ts
+++ b/src/lib/testing/storyboard/compliance.ts
@@ -78,6 +78,27 @@ export const UNBASELINED_SUPPORTED_PROTOCOLS: ReadonlySet<string> = new Set([
   'measurement',
 ]);
 
+/**
+ * Specialism enum values that are deprecated aliases for universal-bundle
+ * storyboards. When an agent declares one of these in
+ * `get_adcp_capabilities.specialisms`, resolution MUST NOT throw
+ * `unknown_specialism` — the bundle lives in `universal/<file>.yaml` and
+ * runs unconditionally already. The deprecated claim is honored for
+ * backward compatibility per the universal storyboard's
+ * "Backward-compatible specialism claims" clause (currently
+ * `signed-requests`; see `universal/signed-requests.yaml` and the
+ * `signed_requests_specialism_deprecated` notice emitted from
+ * `runner.ts:collectCapabilityNotices`).
+ *
+ * Map shape: deprecated specialism enum value → universal bundle base name
+ * (file under `universal/<name>.yaml`, matched against `index.universal`).
+ * Removed in AdCP 4.0 along with the enum value itself
+ * (adcontextprotocol/adcp#3075).
+ */
+export const DEPRECATED_SPECIALISM_UNIVERSAL_ALIASES: Readonly<Record<string, string>> = Object.freeze({
+  'signed-requests': 'signed-requests',
+});
+
 export interface ComplianceIndexProtocol {
   id: string;
   title: string | null;
@@ -821,6 +842,15 @@ export function resolveStoryboardsForCapabilities(
   for (const specialism of declaredSpecialisms) {
     const entry = index.specialisms.find(s => s.id === specialism);
     if (!entry) {
+      // Deprecated alias path: some 3.0-era specialism enum values now resolve
+      // to a `universal/` bundle (e.g. `signed-requests` → `universal/signed-requests.yaml`).
+      // The universal storyboard is pushed unconditionally above; the deprecated
+      // claim is graded there and the deprecation notice fires from runner.ts.
+      // Don't throw — that would block every other storyboard.
+      const universalAlias = DEPRECATED_SPECIALISM_UNIVERSAL_ALIASES[specialism];
+      if (universalAlias && index.universal.includes(universalAlias)) {
+        continue;
+      }
       throw new CapabilityResolutionError({
         code: 'unknown_specialism',
         specialism,
diff --git a/test/lib/storyboard-security.test.js b/test/lib/storyboard-security.test.js
index 4bb984462..feb952385 100644
--- a/test/lib/storyboard-security.test.js
+++ b/test/lib/storyboard-security.test.js
@@ -2390,6 +2390,68 @@ describe('resolveStoryboardsForCapabilities: typed errors', () => {
       fs.rmSync(dir, { recursive: true, force: true });
     }
   });
+
+  // Deprecated `signed-requests` specialism resolves to `universal/signed-requests.yaml`
+  // — must NOT throw unknown_specialism. The universal storyboard runs and the
+  // deprecation notice fires from runner.ts. See adcp-client#2237.
+  it('does NOT throw on deprecated `signed-requests` specialism alias when universal bundle exists', () => {
+    const dir = makeFakeComplianceCache({
+      universalStoryboards: [{ id: 'signed-requests', title: 'Signed requests' }],
+    });
+    try {
+      const { storyboards, not_applicable } = resolveStoryboardsForCapabilities(
+        { specialisms: ['signed-requests'] },
+        { complianceDir: dir }
+      );
+      assert.deepStrictEqual(
+        storyboards.map(s => s.id),
+        ['signed-requests']
+      );
+      assert.deepStrictEqual(not_applicable, []);
+    } finally {
+      fs.rmSync(dir, { recursive: true, force: true });
+    }
+  });
+
+  it('still throws unknown_specialism for non-aliased specialisms without a bundle', () => {
+    const dir = makeFakeComplianceCache({
+      universalStoryboards: [{ id: 'signed-requests', title: 'Signed requests' }],
+    });
+    try {
+      assert.throws(
+        () => resolveStoryboardsForCapabilities({ specialisms: ['not-a-real-specialism'] }, { complianceDir: dir }),
+        err => {
+          assert.ok(err instanceof CapabilityResolutionError);
+          assert.strictEqual(err.code, 'unknown_specialism');
+          assert.strictEqual(err.specialism, 'not-a-real-specialism');
+          return true;
+        }
+      );
+    } finally {
+      fs.rmSync(dir, { recursive: true, force: true });
+    }
+  });
+
+  it('throws unknown_specialism for deprecated alias when the universal bundle is absent (stale cache)', () => {
+    // Cache has neither specialisms/signed-requests/ nor universal/signed-requests.yaml
+    // (e.g. cache pinned to a pre-3.1 version). The deprecated-alias fast path
+    // must require the universal bundle's presence — otherwise we'd silently
+    // skip a real configuration error.
+    const dir = makeFakeComplianceCache({ universalStoryboards: [] });
+    try {
+      assert.throws(
+        () => resolveStoryboardsForCapabilities({ specialisms: ['signed-requests'] }, { complianceDir: dir }),
+        err => {
+          assert.ok(err instanceof CapabilityResolutionError);
+          assert.strictEqual(err.code, 'unknown_specialism');
+          assert.strictEqual(err.specialism, 'signed-requests');
+          return true;
+        }
+      );
+    } finally {
+      fs.rmSync(dir, { recursive: true, force: true });
+    }
+  });
 });
 
 // ────────────────────────────────────────────────────────────
diff --git a/test/server-auto-signed-requests.test.js b/test/server-auto-signed-requests.test.js
index 24e94dae4..92c3375f6 100644
--- a/test/server-auto-signed-requests.test.js
+++ b/test/server-auto-signed-requests.test.js
@@ -181,10 +181,42 @@ async function postSigned({ url, body, sign, nonce }) {
 
 describe('createAdcpServer: signedRequests auto-wiring', () => {
   describe('startup validation', () => {
-    it('throws when signedRequests config is provided without the specialism', () => {
+    // Canonical 3.1+ path: signedRequests config + request_signing.supported:true,
+    // no deprecated `signed-requests` specialism claim. Should boot. The universal
+    // signed_requests storyboard grades on the capability flag alone — the deprecated
+    // claim is only kept for back-compat through the AdCP 4.0 deprecation window.
+    // See adcp-client#2237.
+    it('does not throw when signedRequests + request_signing.supported:true (no deprecated specialism claim)', () => {
+      assert.doesNotThrow(() => createAdcpServer(sellerConfig({ withSignedRequests: true, withSpecialism: false })));
+    });
+
+    it('throws when signedRequests config is provided with neither discovery surface declared', () => {
       assert.throws(
-        () => createAdcpServer(sellerConfig({ withSignedRequests: true, withSpecialism: false })),
-        /specialisms.*does not include "signed-requests"/
+        () =>
+          createAdcpServer({
+            ...sellerConfig({ withSignedRequests: true, withSpecialism: false }),
+            capabilities: {
+              features: { inlineCreativeManagement: false },
+              specialisms: [],
+              // request_signing omitted — no discovery surface at all.
+            },
+          }),
+        err => /request_signing\.supported: true.*specialisms.*signed-requests/.test(err.message)
+      );
+    });
+
+    it('throws when signedRequests + specialism omitted + request_signing.supported:false', () => {
+      assert.throws(
+        () =>
+          createAdcpServer({
+            ...sellerConfig({ withSignedRequests: true, withSpecialism: false }),
+            capabilities: {
+              features: { inlineCreativeManagement: false },
+              specialisms: [],
+              request_signing: { supported: false },
+            },
+          }),
+        err => /request_signing\.supported: true.*specialisms.*signed-requests/.test(err.message)
       );
     });
 
@@ -243,12 +275,23 @@ describe('createAdcpServer: signedRequests auto-wiring', () => {
     });
 
     it('gives the expected error message shape for each misconfiguration pattern', () => {
-      // config + no claim
+      // config + no discovery surface (no claim AND request_signing absent/supported:false)
       assert.throws(
-        () => createAdcpServer(sellerConfig({ withSignedRequests: true, withSpecialism: false })),
-        err => /signedRequests.*is configured but.*specialisms.*does not include "signed-requests"/.test(err.message)
+        () =>
+          createAdcpServer({
+            ...sellerConfig({ withSignedRequests: true, withSpecialism: false }),
+            capabilities: {
+              features: { inlineCreativeManagement: false },
+              specialisms: [],
+              request_signing: { supported: false },
+            },
+          }),
+        err =>
+          /signedRequests.*is configured but neither.*request_signing\.supported: true.*specialisms.*signed-requests/.test(
+            err.message
+          )
       );
-      // claim + supported:false — third guard
+      // claim + supported:false — third guard (back-compat path requires capability flag too)
       assert.throws(
         () =>
           createAdcpServer({