diff --git a/docs/product-catalog.json b/docs/product-catalog.json
index 299e8cc9f..ca86ea0d7 100644
--- a/docs/product-catalog.json
+++ b/docs/product-catalog.json
@@ -671,7 +671,8 @@
       "tools_sha256": "5a88bf598a1e0fe705761db6af92f1ceabaf026cb6efa425e87b9633f1d7a3de",
       "prompts_sha256": "f6da3ad38a1000c11364d1710f122ac4990551f04efd8c53ffb2e819b5cf5707",
       "resources_sha256": "339a984ea8cd8be5f234adf24395bf0295258d990492005cf6fe1f293d12cd46",
-      "combined_sha256": "861cd8618e793342daa8b149bc2944360d84b077fd19cf22f6e0a57b6b249c73"
+      "combined_sha256": "861cd8618e793342daa8b149bc2944360d84b077fd19cf22f6e0a57b6b249c73",
+      "providers_sha256": "918ccd6b8ae442cd5844dcfde55086f458176241c8d166c1e9dd0f242ccd2bb0"
     }
   }
 }
diff --git a/scripts/lib/catalog-core.mjs b/scripts/lib/catalog-core.mjs
index 25fd557e2..e75692c36 100644
--- a/scripts/lib/catalog-core.mjs
+++ b/scripts/lib/catalog-core.mjs
@@ -1,6 +1,9 @@
+import { createHash } from "node:crypto";
 import { join } from "node:path";
 import { pathToFileURL } from "node:url";
 
+import canonicalize from "canonicalize";
+
 const load = (root, path) => import(pathToFileURL(join(root, path)).href);
 
 /** Sort tool/provider names alphabetically. */
@@ -9,6 +12,14 @@ export const names = (contracts) =>
     .map(({ name }) => name)
     .sort((left, right) => left.localeCompare(right));
 
+/** Return the stable digest for a generated catalog projection. */
+export const digest = (value) => {
+  const encoded = canonicalize(value);
+  if (encoded === undefined)
+    throw new TypeError("Catalog projection is not canonical JSON");
+  return createHash("sha256").update(encoded).digest("hex");
+};
+
 /** Throw when two name lists diverge. */
 export const assertSameNames = (label, actual, expected) => {
   const actualSet = new Set(actual);
diff --git a/scripts/lib/product-catalog.d.mts b/scripts/lib/product-catalog.d.mts
index 8dc637cd3..b0a5336d5 100644
--- a/scripts/lib/product-catalog.d.mts
+++ b/scripts/lib/product-catalog.d.mts
@@ -46,6 +46,9 @@ export interface ProductCatalog {
 }
 
 export function createProductCatalog(root: string): Promise<ProductCatalog>;
+export function providerCatalogDigest(
+  providers: ProductCatalog["providers"],
+): string;
 export function createCliInventory(cli: unknown): {
   readonly primary: readonly string[];
   readonly aliases: readonly {
diff --git a/scripts/lib/product-catalog.mjs b/scripts/lib/product-catalog.mjs
index bfc38914d..b676f28d8 100644
--- a/scripts/lib/product-catalog.mjs
+++ b/scripts/lib/product-catalog.mjs
@@ -1,6 +1,6 @@
 import { format } from "prettier";
 
-import { assertSameNames, loadSources } from "./catalog-core.mjs";
+import { assertSameNames, digest, loadSources } from "./catalog-core.mjs";
 import {
   createCliInventory,
   cliCommandDescriptionIssues,
@@ -15,6 +15,9 @@ export {
   cliCommandOptionNames,
 };
 
+/** Return the stable digest for the source-derived provider projection. */
+export const providerCatalogDigest = (providers) => digest(providers);
+
 /** Project current runtime contracts into deterministic, machine-readable facts. */
 export const createProductCatalog = async (root) => {
   const sources = await loadSources(root);
@@ -25,6 +28,7 @@ export const createProductCatalog = async (root) => {
     sources.catalogIdentity.CLI_COMMAND_NAMES,
   );
   const tools = toolFamilyCatalog(sources);
+  const providers = providerCatalog(sources);
   const metadata = sources.packageMetadata.PACKAGE_METADATA;
   return {
     catalog_schema_version: 1,
@@ -39,7 +43,7 @@ export const createProductCatalog = async (root) => {
       skill_version: metadata.skillVersion,
     },
     tools,
-    providers: providerCatalog(sources),
+    providers,
     setup_clients: sources.supportedClients.SUPPORTED_CLIENT_DEFINITIONS.map(
       ({ name, displayName, format }) => ({
         id: name,
@@ -56,7 +60,10 @@ export const createProductCatalog = async (root) => {
     },
     runtime_catalog: {
       counts: sources.catalogIdentity.CATALOG_IDENTITY.counts,
-      digests: sources.catalogIdentity.CATALOG_IDENTITY.digests,
+      digests: {
+        ...sources.catalogIdentity.CATALOG_IDENTITY.digests,
+        providers_sha256: providerCatalogDigest(providers),
+      },
     },
   };
 };
diff --git a/tests/productCatalog.test.ts b/tests/productCatalog.test.ts
index 90bcc567b..63c21af90 100644
--- a/tests/productCatalog.test.ts
+++ b/tests/productCatalog.test.ts
@@ -44,6 +44,7 @@ import {
   cliCommandDescriptionIssues,
   cliCommandOptionNames,
   createProductCatalog,
+  providerCatalogDigest,
   serializeProductCatalog,
 } from "../scripts/lib/product-catalog.mjs";
 
@@ -139,6 +140,9 @@ describe("canonical product catalog", () => {
       "project_managed_application_graph",
       "verify_managed_native_boundaries",
     ]);
+    expect(catalog.runtime_catalog.digests.providers_sha256).toBe(
+      providerCatalogDigest(catalog.providers),
+    );
     expect(
       z.toJSONSchema(analysisSnapshotSchema).properties?.snapshot_version,
     ).toMatchObject({
@@ -230,6 +234,19 @@ describe("canonical product catalog", () => {
     );
   });
 
+  it("changes the provider projection digest when provider facts drift", async () => {
+    const catalog = await createProductCatalog(root);
+    const firstProvider = catalog.providers[0];
+    if (firstProvider === undefined) throw new TypeError("Missing provider");
+    const driftedProviders = [
+      { ...firstProvider, name: `${firstProvider.name} drifted` },
+      ...catalog.providers.slice(1),
+    ];
+    expect(providerCatalogDigest(driftedProviders)).not.toBe(
+      catalog.runtime_catalog.digests.providers_sha256,
+    );
+  });
+
   it("fails check mode without rewriting a stale generated artifact", async () => {
     const directory = await createTestTempDirectory("rea-generated-check-");
     temporaryRoots.push(directory);