diff --git a/changelog.d/fixes/12321-usage-fetcher-registration.md b/changelog.d/fixes/12321-usage-fetcher-registration.md
new file mode 100644
index 0000000000..89574d811c
--- /dev/null
+++ b/changelog.d/fixes/12321-usage-fetcher-registration.md
@@ -0,0 +1 @@
+- **fix(usage):** `adobe-firefly` and `firefly` have had a working usage fetcher since Adobe Firefly landed, but neither was ever added to the registration list, so the provider-plugin manifest, `genericQuotaFetcher` and the free-access quota cache all reported them as having no usage support — while `USAGE_SUPPORTED_PROVIDERS` said the opposite. Both are now declared, which also means their credit balance is fetched like any other declared provider's: `registerGenericQuotaFetchers` now registers a generic quota fetcher for them, and `resolveFreeAccessState` no longer returns early. A test holds the registration list to the dispatcher's switch in both directions, which is what the module's own docstring already asked for in prose ([#12321](https://github.com/diegosouzapw/OmniRoute/pull/12321))
diff --git a/open-sse/services/usage/fetcherProviders.ts b/open-sse/services/usage/fetcherProviders.ts
index d299748933..88af055632 100644
--- a/open-sse/services/usage/fetcherProviders.ts
+++ b/open-sse/services/usage/fetcherProviders.ts
@@ -59,6 +59,14 @@ export const USAGE_FETCHER_PROVIDERS = [
   // PromptQL playground credits (data.pro.ql.app getCreditSummary)
   "promptql",
   "pql",
+  // Adobe Firefly credit balance (GET firefly.adobe.io/v1/credits/balance).
+  // Dispatched since #8006; the registration list was missed at the time, so the
+  // manifest and the quota fetchers reported no usage support for either id.
+  // Declaring them here is what makes `registerGenericQuotaFetchers` wire a
+  // generic fetcher for them and `resolveFreeAccessState` stop returning early —
+  // i.e. the balance is now actually fetched, which is the point.
+  "adobe-firefly",
+  "firefly",
   // HyperAgent billing usage (creditBlocks USD)
   "hyperagent",
   "ha",
diff --git a/tests/unit/usage-fetcher-registration-coverage.test.ts b/tests/unit/usage-fetcher-registration-coverage.test.ts
new file mode 100644
index 0000000000..1a702cbfcb
--- /dev/null
+++ b/tests/unit/usage-fetcher-registration-coverage.test.ts
@@ -0,0 +1,134 @@
+/**
+ * `usage/fetcherProviders.ts` says of itself that it exists "so the registration
+ * list can't drift from the dispatcher's switch statement", and asks whoever adds
+ * a case to remember to add it here too. Nothing enforced that, and it drifted:
+ * #8006 added `adobe-firefly`/`firefly` to the switch and to
+ * `USAGE_SUPPORTED_PROVIDERS` but not to this list, so three consumers
+ * (`genericQuotaFetcher.ts`, `freeAccessQuota.ts`, the provider-plugin manifest)
+ * were told those providers had no usage fetcher when in fact they do.
+ *
+ * This test is the enforcement the comment asked for.
+ */
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import path from "node:path";
+import test from "node:test";
+import { fileURLToPath } from "node:url";
+
+import { USAGE_FETCHER_PROVIDERS } from "../../open-sse/services/usage/fetcherProviders.ts";
+import { USAGE_SUPPORTED_PROVIDERS } from "../../src/shared/constants/providers.ts";
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+
+/**
+ * The provider ids `getUsageForProvider` actually dispatches on. Read from the
+ * source rather than by calling the function: importing the dispatcher pulls in
+ * its whole fetcher graph (DB, sockets, child_process), which is precisely the
+ * weight `fetcherProviders.ts` was extracted to avoid.
+ */
+function dispatchedProviderIds(): string[] {
+  const source = fs.readFileSync(path.resolve(here, "../../open-sse/services/usage.ts"), "utf8");
+
+  // Anchor on the dispatcher itself, not on the first occurrence of the word
+  // "switch" -- that one is in a doc comment twenty lines above it. Then stop at
+  // the closing brace of that switch, so a second switch added later in the file
+  // cannot contribute cases to an invariant that is only about this one.
+  const start = source.indexOf("switch (provider) {");
+  assert.notEqual(start, -1, "could not find `switch (provider) {` in services/usage.ts");
+  assert.equal(
+    source.indexOf("switch (provider) {", start + 1),
+    -1,
+    "more than one `switch (provider)` — this reader would merge them"
+  );
+
+  let depth = 0;
+  let end = start;
+  for (let i = source.indexOf("{", start); i < source.length; i += 1) {
+    if (source[i] === "{") depth += 1;
+    else if (source[i] === "}") {
+      depth -= 1;
+      if (depth === 0) {
+        end = i;
+        break;
+      }
+    }
+  }
+  assert.ok(end > start, "unbalanced braces in the dispatcher switch");
+
+  const body = source.slice(start, end);
+  const ids = [...body.matchAll(/^\s*case ["']([^"']+)["']:/gm)].map((match) => match[1]);
+  assert.ok(ids.length > 0, "parsed no cases out of the dispatcher — the reader is broken");
+  return [...new Set(ids)];
+}
+
+test("every provider the dispatcher handles is declared as having a fetcher", () => {
+  const undeclared = dispatchedProviderIds().filter(
+    (id) => !(USAGE_FETCHER_PROVIDERS as readonly string[]).includes(id)
+  );
+  assert.deepEqual(
+    undeclared,
+    [],
+    "these providers have a usage fetcher the dispatcher will happily call, but nothing " +
+      "declares it — so genericQuotaFetcher, freeAccessQuota and the plugin manifest all " +
+      "report them as having no usage support: " +
+      undeclared.join(", ")
+  );
+});
+
+test("nothing is declared that the dispatcher would not handle", () => {
+  const dispatched = dispatchedProviderIds();
+  const phantom = (USAGE_FETCHER_PROVIDERS as readonly string[]).filter(
+    (id) => !dispatched.includes(id)
+  );
+  assert.deepEqual(
+    phantom,
+    [],
+    `declared but unreachable, so a quota fetch would silently return nothing: ${phantom.join(", ")}`
+  );
+});
+
+/**
+ * The fetcher list and the "usage supported" connection list are not the same
+ * set, and should not be forced to converge — but every difference needs a
+ * reason on record, or the next drift hides among the ones we accepted.
+ */
+const ACCEPTED_DIVERGENCE: Record<string, string> = {
+  // Aggregators: a usage fetcher exists, but a connection to them is not itself
+  // presented as a usage-reporting account in the UI.
+  opencode: "aggregator — fetcher exists, not surfaced as a usage-reporting connection",
+  "opencode-zen": "aggregator — same as opencode",
+  xai: "reached through xai-oauth for connection purposes",
+  openrouter: "aggregator — fetcher exists, not surfaced as a usage-reporting connection",
+  // Declared supported, no fetcher: a real gap, left alone here on purpose so
+  // this PR stays about the two providers whose fetcher already exists.
+  "xiaomi-mimo-token-plan": "declared supported with no fetcher — open question, not fixed here",
+};
+
+test("every difference between the two lists is one we have written down", () => {
+  const fetcher = new Set<string>(USAGE_FETCHER_PROVIDERS as readonly string[]);
+  const supported = new Set<string>(USAGE_SUPPORTED_PROVIDERS as readonly string[]);
+  const unexplained = [
+    ...[...fetcher].filter((id) => !supported.has(id)),
+    ...[...supported].filter((id) => !fetcher.has(id)),
+  ].filter((id) => !(id in ACCEPTED_DIVERGENCE));
+
+  assert.deepEqual(
+    unexplained,
+    [],
+    "the two lists differ here for no recorded reason — either wire it up, or add it to " +
+      `ACCEPTED_DIVERGENCE with why: ${unexplained.join(", ")}`
+  );
+});
+
+test("the recorded divergences are still real, so the list does not rot", () => {
+  const fetcher = new Set<string>(USAGE_FETCHER_PROVIDERS as readonly string[]);
+  const supported = new Set<string>(USAGE_SUPPORTED_PROVIDERS as readonly string[]);
+  const stale = Object.keys(ACCEPTED_DIVERGENCE).filter(
+    (id) => fetcher.has(id) === supported.has(id)
+  );
+  assert.deepEqual(
+    stale,
+    [],
+    `these no longer differ; drop them from ACCEPTED_DIVERGENCE: ${stale.join(", ")}`
+  );
+});