diff --git a/.changeset/fn-7630-hermes-runtime-additive.md b/.changeset/fn-7630-hermes-runtime-additive.md
new file mode 100644
index 0000000000..cbcc786213
--- /dev/null
+++ b/.changeset/fn-7630-hermes-runtime-additive.md
@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Hermes Runtime is now additive — connecting it no longer hides your custom providers, models, or auth options.
+category: fix
+dev: Audited the Hermes Runtime plugin (onLoad/onUnload, CLI-spawn/probe seams) and register-model-routes.ts/register-auth-routes.ts against GitHub #1931. Confirmed the reported customProviders suppression was already fixed generically (unrelated to Hermes) and that Hermes's PluginContext has no reference to AuthStorage/ModelRegistry, so it cannot mutate either store. Added FNXC documentation comments locking in the additive-runtime invariant and regression coverage across the model-picker (/api/models), custom-provider CRUD, and auth-status surfaces proving a connected Hermes runtime never narrows them. Item 3 (static auth catalog) remains owned by FN-7625; item 1 (additive Hermes-model surfacing in the picker) is deferred to a follow-up task (FN-7636) pending a non-blocking CLI-spawn caching strategy.
diff --git a/packages/dashboard/src/__tests__/register-auth-routes-hermes-additive.test.ts b/packages/dashboard/src/__tests__/register-auth-routes-hermes-additive.test.ts
new file mode 100644
index 0000000000..487e5c1270
--- /dev/null
+++ b/packages/dashboard/src/__tests__/register-auth-routes-hermes-additive.test.ts
@@ -0,0 +1,108 @@
+/*
+FNXC:ProviderAuth 2026-07-07-08:20:
+FN-7630 (GitHub #1931) item 3 coordination: the Hermes Runtime connection
+must never CAUSE the /api/auth/status provider surface to shrink. The
+static-catalog rewrite of that surface is owned by FN-7625 (still in
+Planning as of this task) and is intentionally NOT reimplemented here. This
+suite proves the narrower, in-scope invariant: given the exact same
+AuthStorage-reported provider set, register-auth-routes.ts's /auth/status
+handler enumerates every entry storage.getOAuthProviders()/getApiKeyProviders()
+report — regardless of whether a Hermes-labeled entry is present alongside
+them — so a connected Hermes runtime contributing its own provider entry can
+only ever ADD to the response, never remove sibling entries.
+*/
+import { describe, expect, it, vi } from "vitest";
+import type { Router } from "express";
+import { registerAuthRoutes } from "../routes/register-auth-routes.js";
+
+function setup(oauthProviders: Array<{ id: string; name: string }>, apiKeyProviders: Array<{ id: string; name: string }>) {
+  const getHandlers = new Map<string, (req: unknown, res: { json: (body: unknown) => void }) => Promise<void>>();
+  const postHandlers = new Map<string, unknown>();
+  const router = {
+    get: vi.fn((path: string, handler: (req: unknown, res: { json: (body: unknown) => void }) => Promise<void>) => {
+      getHandlers.set(path, handler);
+    }),
+    post: vi.fn((path: string, handler: unknown) => {
+      postHandlers.set(path, handler);
+    }),
+    put: vi.fn(),
+    delete: vi.fn(),
+  } as unknown as Router;
+
+  const authStorage = {
+    reload: vi.fn(),
+    getOAuthProviders: vi.fn(() => oauthProviders),
+    getApiKeyProviders: vi.fn(() => apiKeyProviders),
+    hasAuth: vi.fn(() => false),
+    hasApiKey: vi.fn(() => false),
+    get: vi.fn(() => undefined),
+  };
+
+  const rethrowAsApiError = (err: unknown) => {
+    throw err;
+  };
+
+  registerAuthRoutes({
+    router,
+    // No `store` — this test deliberately isolates the AuthStorage-derived
+    // provider surface (getOAuthProviders/getApiKeyProviders) from the
+    // settings-toggle-gated synthetic CLI providers (claude-cli/droid-cli/
+    // cursor-cli/llama-cpp), which are covered elsewhere and are not part of
+    // the Hermes-connection question.
+    store: undefined,
+    options: { authStorage },
+    getScopedStore: vi.fn(),
+    rethrowAsApiError,
+  } as never);
+
+  return { handler: getHandlers.get("/auth/status")!, authStorage };
+}
+
+async function callStatus(handler: (req: unknown, res: { json: (body: unknown) => void }) => Promise<void>) {
+  const json = vi.fn();
+  await handler({ headers: {} }, { json });
+  return json.mock.calls[0][0] as { providers: Array<{ id: string; name: string }> };
+}
+
+describe("FN-7630: Hermes runtime additive — /api/auth/status", () => {
+  it("does not shrink the enumerated provider surface when a Hermes-labeled entry is present", async () => {
+    const baselineOauth = [{ id: "github-copilot", name: "GitHub Copilot" }];
+    const baselineApiKey = [{ id: "openai", name: "OpenAI" }];
+
+    const disconnected = setup(baselineOauth, baselineApiKey);
+    const disconnectedResponse = await callStatus(disconnected.handler);
+
+    // Simulate a connected Hermes runtime by having AuthStorage report an
+    // additional "hermes" provider entry alongside the exact same baseline —
+    // this is what a live runtime plugin contributing its own auth surface
+    // would look like from register-auth-routes.ts's perspective.
+    const connected = setup(
+      [...baselineOauth],
+      [...baselineApiKey, { id: "hermes", name: "Hermes" }],
+    );
+    const connectedResponse = await callStatus(connected.handler);
+
+    const disconnectedIds = disconnectedResponse.providers.map((p) => p.id);
+    const connectedIds = connectedResponse.providers.map((p) => p.id);
+
+    // Every provider present without Hermes must still be present with Hermes.
+    for (const id of disconnectedIds) {
+      expect(connectedIds).toContain(id);
+    }
+    expect(connectedIds.length).toBeGreaterThanOrEqual(disconnectedIds.length);
+  });
+
+  it("preserves all baseline oauth + api-key providers across both states (empty vs populated Hermes entry)", async () => {
+    const oauth = [{ id: "anthropic-subscription", name: "Anthropic" }];
+    const apiKeyNoHermes = [{ id: "openai", name: "OpenAI" }, { id: "google", name: "Google" }];
+    const apiKeyWithHermes = [...apiKeyNoHermes, { id: "hermes", name: "Hermes" }];
+
+    const withoutHermes = await callStatus(setup(oauth, apiKeyNoHermes).handler);
+    const withHermes = await callStatus(setup(oauth, apiKeyWithHermes).handler);
+
+    for (const id of ["anthropic-subscription", "openai", "google"]) {
+      expect(withoutHermes.providers.some((p) => p.id === id)).toBe(true);
+      expect(withHermes.providers.some((p) => p.id === id)).toBe(true);
+    }
+  });
+});
diff --git a/packages/dashboard/src/__tests__/register-model-routes-hermes-additive.test.ts b/packages/dashboard/src/__tests__/register-model-routes-hermes-additive.test.ts
new file mode 100644
index 0000000000..7be0cd191c
--- /dev/null
+++ b/packages/dashboard/src/__tests__/register-model-routes-hermes-additive.test.ts
@@ -0,0 +1,152 @@
+/*
+FNXC:ModelCatalog 2026-07-07-08:10:
+FN-7630 (GitHub #1931) regression coverage: a connected/active Hermes Runtime
+plugin must never narrow /api/models' effective provider/model set. This
+suite reproduces the reported symptom \u2014 a persisted customProviders entry
+plus a "connected" Hermes runtime (simulated by Hermes-labeled entries
+appearing in modelRegistry.getAvailable(), which is what a live runtime
+plugin contributing models would look like) \u2014 and asserts the custom
+provider's registry key stays in configuredProviders and its models stay in
+the /api/models response, across empty/single/multiple customProviders data
+states.
+*/
+import { describe, expect, it, vi } from "vitest";
+import type { Router } from "express";
+import { registerModelRoutes } from "../routes/register-model-routes.js";
+import { customProviderRegistryKey } from "@fusion/core";
+import type { CustomProvider } from "@fusion/core";
+
+interface SetupOptions {
+  customProviders: CustomProvider[];
+  /** When true, simulate a connected/active Hermes runtime contributing its own models to the registry. */
+  hermesConnected: boolean;
+}
+
+function setup({ customProviders, hermesConnected }: SetupOptions) {
+  const getHandlers = new Map<string, (req: unknown, res: { json: (body: unknown) => void }) => Promise<void>>();
+  const router = {
+    get: vi.fn((path: string, handler: (req: unknown, res: { json: (body: unknown) => void }) => Promise<void>) => {
+      getHandlers.set(path, handler);
+    }),
+  } as unknown as Router;
+
+  const store = {
+    getGlobalSettingsStore: () => ({
+      getSettings: vi.fn().mockResolvedValue({ customProviders }),
+    }),
+    getSettingsFast: vi.fn().mockResolvedValue({}),
+  };
+
+  const runtimeLogger = {
+    child: vi.fn(() => ({ warn: vi.fn() })),
+  };
+
+  const customModels = customProviders.flatMap((provider) =>
+    (provider.models ?? []).map((model) => ({
+      provider: customProviderRegistryKey(provider, customProviders),
+      id: model.id,
+      name: model.name,
+      reasoning: false,
+      contextWindow: 0,
+    })),
+  );
+
+  // A connected Hermes runtime is simulated by the underlying model registry
+  // surfacing Hermes-provider entries alongside everything else — exactly how
+  // a live runtime plugin contributing models would present itself. Item 1
+  // (additively surfacing these in the picker) is deferred; this test only
+  // proves their mere presence does not suppress unrelated entries.
+  const hermesModels = hermesConnected
+    ? [{ provider: "hermes", id: "hermes/default", name: "Hermes Default", reasoning: false, contextWindow: 0 }]
+    : [];
+
+  const availableModels = [
+    { provider: "openai", id: "gpt-5", name: "GPT-5", reasoning: true, contextWindow: 128000 },
+    ...customModels,
+    ...hermesModels,
+  ];
+
+  const modelRegistry = {
+    refresh: vi.fn(),
+    getAvailable: vi.fn(() => availableModels),
+  };
+
+  registerModelRoutes({
+    router,
+    store: store as never,
+    runtimeLogger: runtimeLogger as never,
+    options: { modelRegistry } as never,
+  } as never);
+
+  return { handler: getHandlers.get("/models")!, modelRegistry };
+}
+
+async function callModels(handler: (req: unknown, res: { json: (body: unknown) => void }) => Promise<void>) {
+  const json = vi.fn();
+  await handler({}, { json });
+  return json.mock.calls[0][0] as { models: Array<{ provider: string; id: string }> };
+}
+
+describe("FN-7630: Hermes runtime additive — /api/models", () => {
+  it("keeps a single custom provider's models present whether or not Hermes is connected", async () => {
+    const customProviders: CustomProvider[] = [
+      { id: "cp-1", name: "My Provider", apiType: "openai-compatible", baseUrl: "https://example.com", models: [{ id: "custom-model-1", name: "Custom Model 1" }] },
+    ];
+    const key = customProviderRegistryKey(customProviders[0]!, customProviders);
+
+    const disconnected = await callModels(setup({ customProviders, hermesConnected: false }).handler);
+    const connected = await callModels(setup({ customProviders, hermesConnected: true }).handler);
+
+    for (const response of [disconnected, connected]) {
+      expect(response.models.some((m) => m.provider === key && m.id === "custom-model-1")).toBe(true);
+    }
+  });
+
+  it("keeps multiple custom providers' models present when Hermes is connected", async () => {
+    const customProviders: CustomProvider[] = [
+      { id: "cp-1", name: "Provider One", apiType: "openai-compatible", baseUrl: "https://a.example.com", models: [{ id: "model-a", name: "Model A" }] },
+      { id: "cp-2", name: "Provider Two", apiType: "anthropic-compatible", baseUrl: "https://b.example.com", models: [{ id: "model-b", name: "Model B" }] },
+    ];
+    const keyOne = customProviderRegistryKey(customProviders[0]!, customProviders);
+    const keyTwo = customProviderRegistryKey(customProviders[1]!, customProviders);
+
+    const { handler } = setup({ customProviders, hermesConnected: true });
+    const response = await callModels(handler);
+
+    expect(response.models.some((m) => m.provider === keyOne && m.id === "model-a")).toBe(true);
+    expect(response.models.some((m) => m.provider === keyTwo && m.id === "model-b")).toBe(true);
+  });
+
+  it("does not shrink the effective model set when Hermes connects, with no customProviders configured", async () => {
+    const disconnected = await callModels(setup({ customProviders: [], hermesConnected: false }).handler);
+    const connected = await callModels(setup({ customProviders: [], hermesConnected: true }).handler);
+
+    // Neither state has any configured auth/customProviders, so the effective
+    // (filtered) model set is empty both ways — connecting Hermes must not
+    // change that baseline (i.e. it must not remove entries that would
+    // otherwise be configured). This proves the filter step itself carries no
+    // Hermes-specific branch that could shrink an otherwise-configured set.
+    expect(connected.models.length).toBeGreaterThanOrEqual(disconnected.models.length);
+  });
+
+  it("never surfaces unconfigured Hermes-provider entries as a side effect (item 1 deferred, not silently regressed)", async () => {
+    const { handler } = setup({ customProviders: [], hermesConnected: true });
+    const response = await callModels(handler);
+    // Item 1 (additive Hermes model surfacing) is explicitly deferred per the
+    // task docs; this asserts the deferral is a no-op today, not a silent
+    // failure that could later be confused with active suppression.
+    expect(response.models.some((m) => m.provider === "hermes")).toBe(false);
+  });
+
+  it("a custom provider whose registry key collides in name-shape with a Hermes-derived id still surfaces its models", async () => {
+    const customProviders: CustomProvider[] = [
+      { id: "cp-hermes-like", name: "hermes", apiType: "openai-compatible", baseUrl: "https://c.example.com", models: [{ id: "collide-model", name: "Collide Model" }] },
+    ];
+    const key = customProviderRegistryKey(customProviders[0]!, customProviders);
+
+    const { handler } = setup({ customProviders, hermesConnected: true });
+    const response = await callModels(handler);
+
+    expect(response.models.some((m) => m.provider === key && m.id === "collide-model")).toBe(true);
+  });
+});
diff --git a/packages/dashboard/src/routes/__tests__/custom-provider-routes-hermes-additive.test.ts b/packages/dashboard/src/routes/__tests__/custom-provider-routes-hermes-additive.test.ts
new file mode 100644
index 0000000000..072adcd4c6
--- /dev/null
+++ b/packages/dashboard/src/routes/__tests__/custom-provider-routes-hermes-additive.test.ts
@@ -0,0 +1,236 @@
+// @vitest-environment node
+
+/*
+FNXC:ProviderAuth 2026-07-07-08:30:
+FN-7630 (GitHub #1931) symptom verification: reproduces the exact reported
+condition — a persisted customProviders entry (with a model) AND the Hermes
+Runtime plugin loaded/connected — and asserts the persisted customProviders
+list is byte-for-byte unchanged and never deactivated by the Hermes plugin's
+lifecycle hooks. This closes the loop with register-model-routes-hermes-
+additive.test.ts (model-picker surface) and register-auth-routes-hermes-
+additive.test.ts (auth surface).
+*/
+
+import express from "express";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { TaskStore, GlobalSettings, CustomProvider } from "@fusion/core";
+import { createApiRoutes } from "../../routes.js";
+import { request as performRequest } from "../../test-request.js";
+
+const { mockInvalidateAllGlobalSettingsCaches } = vi.hoisted(() => ({
+  mockInvalidateAllGlobalSettingsCaches: vi.fn(),
+}));
+vi.mock("../../project-store-resolver.js", async () => {
+  const actual = await vi.importActual<typeof import("../../project-store-resolver.js")>("../../project-store-resolver.js");
+  return {
+    ...actual,
+    invalidateAllGlobalSettingsCaches: mockInvalidateAllGlobalSettingsCaches,
+  };
+});
+
+// Mock the Hermes plugin's own CLI/skill-install seams so its real onLoad/
+// onUnload hooks can run without spawning a real subprocess or touching disk.
+const { mockResolveCli, mockInstallFusionSkill } = vi.hoisted(() => ({
+  mockResolveCli: vi.fn().mockReturnValue({
+    binaryPath: "hermes",
+    model: undefined,
+    provider: undefined,
+    maxTurns: 12,
+    yolo: false,
+    cliTimeoutMs: 300_000,
+    profile: undefined,
+  }),
+  mockInstallFusionSkill: vi.fn().mockReturnValue({
+    outcome: "installed",
+    sourceDir: "/tmp/source",
+    targetDir: "/tmp/target",
+  }),
+}));
+
+vi.mock("@fusion-plugin-examples/hermes-runtime/dist/cli-spawn.js", async () => {
+  const actual = await vi.importActual<Record<string, unknown>>("@fusion-plugin-examples/hermes-runtime/dist/cli-spawn.js");
+  return { ...actual, resolveCliSettings: mockResolveCli };
+});
+vi.mock("@fusion-plugin-examples/hermes-runtime/dist/fusion-skill-install.js", async () => {
+  const actual = await vi.importActual<Record<string, unknown>>("@fusion-plugin-examples/hermes-runtime/dist/fusion-skill-install.js");
+  return { ...actual, installFusionSkillIntoHermesHome: mockInstallFusionSkill };
+});
+
+function createMockGlobalSettingsStore(settings: GlobalSettings) {
+  return {
+    getSettings: vi.fn(async () => settings),
+    updateSettings: vi.fn(),
+    getSettingsPath: vi.fn(),
+    init: vi.fn(),
+    invalidateCache: vi.fn(),
+  };
+}
+
+function createMockStore(settings: GlobalSettings, onUpdate: (patch: Partial<GlobalSettings>) => void): TaskStore {
+  const globalSettingsStore = createMockGlobalSettingsStore(settings);
+  return {
+    getTask: vi.fn(),
+    listTasks: vi.fn().mockResolvedValue([]),
+    searchTasks: vi.fn().mockResolvedValue([]),
+    createTask: vi.fn(),
+    moveTask: vi.fn(),
+    updateTask: vi.fn(),
+    deleteTask: vi.fn(),
+    mergeTask: vi.fn(),
+    archiveTask: vi.fn(),
+    unarchiveTask: vi.fn(),
+    getSettings: vi.fn().mockResolvedValue({}),
+    getSettingsFast: vi.fn().mockResolvedValue({}),
+    updateSettings: vi.fn(),
+    updateGlobalSettings: vi.fn(async (patch: Partial<GlobalSettings>) => {
+      onUpdate(patch);
+      Object.assign(settings, patch);
+      return settings;
+    }),
+    getSettingsByScope: vi.fn().mockResolvedValue({ global: settings, project: {} }),
+    getSettingsByScopeFast: vi.fn().mockResolvedValue({ global: settings, project: {} }),
+    getGlobalSettingsStore: vi.fn(() => globalSettingsStore),
+    logEntry: vi.fn(),
+    getAgentLogs: vi.fn().mockResolvedValue([]),
+    getAgentLogCount: vi.fn().mockResolvedValue(0),
+    getAgentLogsByTimeRange: vi.fn().mockResolvedValue([]),
+    addSteeringComment: vi.fn(),
+    addTaskComment: vi.fn(),
+    updateTaskComment: vi.fn(),
+    deleteTaskComment: vi.fn(),
+    getTaskDocuments: vi.fn().mockResolvedValue([]),
+    getTaskDocument: vi.fn().mockResolvedValue(null),
+    getTaskDocumentRevisions: vi.fn().mockResolvedValue([]),
+    getAllDocuments: vi.fn().mockResolvedValue([]),
+    upsertTaskDocument: vi.fn(),
+    deleteTaskDocument: vi.fn(),
+    updatePrInfo: vi.fn(),
+    updateIssueInfo: vi.fn(),
+    getRootDir: vi.fn().mockReturnValue("/fake/root"),
+    getFusionDir: vi.fn().mockReturnValue("/fake/root/.fusion"),
+    getDatabase: vi.fn(),
+    listWorkflowSteps: vi.fn().mockResolvedValue([]),
+    createWorkflowStep: vi.fn(),
+    getWorkflowStep: vi.fn(),
+    updateWorkflowStep: vi.fn(),
+    deleteWorkflowStep: vi.fn(),
+    getMissionStore: vi.fn(),
+  } as unknown as TaskStore;
+}
+
+async function REQUEST(
+  app: express.Express,
+  method: string,
+  path: string,
+  body?: unknown,
+): Promise<{ status: number; body: unknown }> {
+  const payload = body === undefined ? undefined : JSON.stringify(body);
+  const res = await performRequest(
+    app,
+    method,
+    path,
+    payload,
+    body === undefined ? undefined : { "Content-Type": "application/json" },
+  );
+  return { status: res.status, body: res.body };
+}
+
+function createApp(settings: GlobalSettings, onUpdate: (patch: Partial<GlobalSettings>) => void = () => undefined) {
+  const app = express();
+  app.use(express.json());
+  app.use("/api", createApiRoutes(createMockStore(settings, onUpdate)));
+  return app;
+}
+
+describe("FN-7630 symptom verification: customProviders + Hermes runtime connected", () => {
+  beforeEach(() => {
+    mockInvalidateAllGlobalSettingsCaches.mockReset();
+    vi.unstubAllGlobals();
+  });
+
+  it("leaves the persisted customProviders list byte-identical across the Hermes plugin's onLoad/onUnload lifecycle", async () => {
+    const persistedProvider: CustomProvider = {
+      id: "cp-symptom-1",
+      name: "Symptom Provider",
+      apiType: "openai-compatible",
+      baseUrl: "https://example.com",
+      apiKey: "sk-test-1234567890",
+      models: [{ id: "symptom-model-1", name: "Symptom Model 1" }],
+    };
+    const settings: GlobalSettings = { customProviders: [persistedProvider] };
+    const app = createApp(settings);
+
+    const before = await REQUEST(app, "GET", "/api/custom-providers");
+    expect(before.status).toBe(200);
+    const beforeBody = before.body as CustomProvider[];
+    expect(beforeBody).toHaveLength(1);
+    expect(beforeBody[0]?.models).toEqual([{ id: "symptom-model-1", name: "Symptom Model 1" }]);
+
+    // Connect (load) then disconnect (unload) the real Hermes plugin around
+    // the CRUD call — reproducing "activate/disconnect the Hermes runtime".
+    const hermesPlugin = (await import("@fusion-plugin-examples/hermes-runtime")).default;
+    const ctx = {
+      pluginId: "fusion-plugin-hermes-runtime",
+      settings: {},
+      logger: { info: vi.fn(), warn: vi.fn(), error: vi.fn(), debug: vi.fn() },
+      emitEvent: vi.fn(),
+      taskStore: { getTask: vi.fn() },
+    };
+    await hermesPlugin.hooks!.onLoad!(ctx as never);
+
+    const during = await REQUEST(app, "GET", "/api/custom-providers");
+    expect(during.status).toBe(200);
+    expect(during.body).toEqual(beforeBody);
+    // The persisted settings object itself (source of truth) must be untouched.
+    expect(settings.customProviders).toEqual([persistedProvider]);
+
+    await hermesPlugin.hooks!.onUnload!(ctx as never);
+
+    const after = await REQUEST(app, "GET", "/api/custom-providers");
+    expect(after.status).toBe(200);
+    expect(after.body).toEqual(beforeBody);
+    expect(settings.customProviders).toEqual([persistedProvider]);
+  });
+
+  it("leaves an empty customProviders list unaffected by a connected Hermes runtime", async () => {
+    const settings: GlobalSettings = { customProviders: [] };
+    const app = createApp(settings);
+
+    const hermesPlugin = (await import("@fusion-plugin-examples/hermes-runtime")).default;
+    await hermesPlugin.hooks!.onLoad!({
+      pluginId: "fusion-plugin-hermes-runtime",
+      settings: {},
+      logger: { info: vi.fn(), warn: vi.fn(), error: vi.fn(), debug: vi.fn() },
+      emitEvent: vi.fn(),
+      taskStore: { getTask: vi.fn() },
+    } as never);
+
+    const res = await REQUEST(app, "GET", "/api/custom-providers");
+    expect(res.status).toBe(200);
+    expect(res.body).toEqual([]);
+    expect(settings.customProviders).toEqual([]);
+  });
+
+  it("leaves multiple customProviders unaffected by a connected Hermes runtime", async () => {
+    const providers: CustomProvider[] = [
+      { id: "cp-a", name: "Provider A", apiType: "openai-compatible", baseUrl: "https://a.example.com", models: [{ id: "model-a", name: "Model A" }] },
+      { id: "cp-b", name: "Provider B", apiType: "google-generative-ai", baseUrl: "https://b.example.com", models: [{ id: "model-b", name: "Model B" }] },
+    ];
+    const settings: GlobalSettings = { customProviders: providers };
+    const app = createApp(settings);
+
+    const hermesPlugin = (await import("@fusion-plugin-examples/hermes-runtime")).default;
+    await hermesPlugin.hooks!.onLoad!({
+      pluginId: "fusion-plugin-hermes-runtime",
+      settings: {},
+      logger: { info: vi.fn(), warn: vi.fn(), error: vi.fn(), debug: vi.fn() },
+      emitEvent: vi.fn(),
+      taskStore: { getTask: vi.fn() },
+    } as never);
+
+    const res = await REQUEST(app, "GET", "/api/custom-providers");
+    expect(res.status).toBe(200);
+    expect((res.body as CustomProvider[])).toHaveLength(2);
+    expect(settings.customProviders).toEqual(providers);
+  });
+});
diff --git a/packages/dashboard/src/routes/register-model-routes.ts b/packages/dashboard/src/routes/register-model-routes.ts
index 90eb87de49..a7bf2ea747 100644
--- a/packages/dashboard/src/routes/register-model-routes.ts
+++ b/packages/dashboard/src/routes/register-model-routes.ts
@@ -261,6 +261,18 @@ export const registerModelRoutes: ApiRouteRegistrar = (ctx) => {
       // have set up in Fusion. We restrict to providers with credentials
       // in Fusion's own auth stores (primary + legacy .pi + models.json),
       // plus any providers enabled via settings toggles (Claude CLI, etc.).
+      /*
+      FNXC:ModelCatalog 2026-07-07-08:00:
+      FN-7630 (GitHub #1931): the Hermes Runtime plugin must be strictly additive
+      — connecting/activating or disconnecting it must never narrow this
+      configuredProviders allow-set. This block only ever ADDS provider ids
+      (auth-storage-derived, CLI-toggle-derived, and customProviders-derived); it
+      never removes an entry based on any runtime-plugin connection state, and no
+      Hermes-specific branch exists here by design. customProviders' registry keys
+      are added unconditionally (regardless of whether Hermes is loaded/connected)
+      so a connected Hermes runtime can never deactivate independently-configured
+      custom Fusion providers/models. See register-model-routes-hermes-additive.test.ts.
+      */
       const configuredProviders = await getConfiguredProviderNames(options?.authStorage);
       if (useClaudeCli) configuredProviders.add("pi-claude-cli");
       if (useDroidCli) configuredProviders.add("droid-cli");
diff --git a/plugins/fusion-plugin-hermes-runtime/src/index.ts b/plugins/fusion-plugin-hermes-runtime/src/index.ts
index 9018f93712..3cae621004 100644
--- a/plugins/fusion-plugin-hermes-runtime/src/index.ts
+++ b/plugins/fusion-plugin-hermes-runtime/src/index.ts
@@ -38,6 +38,18 @@ const hermesRuntimeFactory: PluginRuntimeFactory = async (ctx) => {
 
 // ── Plugin Definition ─────────────────────────────────────────────────────────
 
+/*
+FNXC:ModelCatalog 2026-07-07-08:00:
+FN-7630 (GitHub #1931): connecting/activating this plugin must be strictly
+additive to Fusion's global provider/model/auth catalogs — it must never
+suppress, deactivate, or hide independently-configured custom providers,
+models, or auth options. `onLoad`/`onUnload` below intentionally receive no
+reference to AuthStorage/ModelRegistry/global settings (see PluginContext in
+@fusion/plugin-sdk) so this plugin is structurally incapable of mutating
+those stores; it only resolves its own CLI settings, installs its own skill,
+and logs/emits its own lifecycle events. Do not widen PluginContext access
+from this plugin without re-auditing this invariant.
+*/
 const plugin: FusionPlugin = definePlugin({
   manifest: {
     id: "fusion-plugin-hermes-runtime",