diff --git a/README.md b/README.md
index fab23bb..2256c2b 100644
--- a/README.md
+++ b/README.md
@@ -61,12 +61,25 @@ enforceable and grantable through the exact same `requirePermission` middleware
 claimable by a module. `pnpm doctor` and `pnpm modules:validate` both validate permission
 composition. Installing, removing, or editing a module currently requires an API restart; removing
 one makes its permission unavailable to new checks and new grants without deleting or revoking any
-historical grant or audit row. Module HTTP route registration and relationship-derived grant
-creation remain later work. See
+historical grant or audit row. See
 [Authorization](docs/development/authorization.md#module-permission-composition),
 [Module development](docs/module-development/README.md), and
 [ADR 0014](docs/architecture/decisions/0014-module-permission-declarations-and-platform-registry.md).
 
+Phase 5B mounts a module's own HTTP routes in production. A module registers framework-neutral
+Fetch (`Request`/`Response`) route handlers during its existing `register` hook; Core collects them
+into an immutable snapshot alongside its capabilities, and `apps/api` discovers modules exactly
+once, starts the module runtime from that same discovered inventory, and mounts its published
+routes under `/api/v1/modules/<module-id>` — after every module has registered and started
+successfully, so no request can reach a module before startup completes. Every route is enforced
+through the identical `requirePermission` middleware and composed permission registry Core's own
+routes use (a module can never supply its own baseline), state-changing methods require a trusted
+`Origin`, and a handler failure or non-`Response` return becomes a fixed, sanitized `500` — never a
+raw error, stack, path, or permission id. Relationship-derived grant creation remains later work.
+See [API](docs/development/api.md#module-http-routes),
+[Module development](docs/module-development/README.md#http-routes), and
+[ADR 0014](docs/architecture/decisions/0014-module-permission-declarations-and-platform-registry.md#deferred).
+
 ## Quick start
 
 Prerequisites: Node.js 24 LTS, pnpm 11.12, and Docker with Compose.
diff --git a/apps/api/src/app.ts b/apps/api/src/app.ts
index fce51be..3207bd0 100644
--- a/apps/api/src/app.ts
+++ b/apps/api/src/app.ts
@@ -1,4 +1,4 @@
-import { isAuthenticatedPrincipal } from "@ekklesia/contracts";
+import { isAuthenticatedPrincipal, type RegisteredModuleHttpRoute } from "@ekklesia/contracts";
 import type {
   AuthorizationEvaluator,
   AuthorizationStore,
@@ -9,23 +9,30 @@ import { Hono } from "hono";
 import type { Context } from "hono";
 import { cors } from "hono/cors";
 import { createGrantsRoutes } from "./grants-routes.js";
+import { mountModuleHttpRoutes } from "./module-http-routes.js";
 
 export interface CreateApiAppAuthorizationOptions {
   readonly evaluator: AuthorizationEvaluator;
   /** The complete platform permission registry (Core's own declarations plus every installed
    * module's) — always the caller-composed registry `startApi` produces via
-   * `composeStartupPermissionRegistry`, never a Core-only fallback constructed here. */
+   * `prepareStartupModuleInventory`, never a Core-only fallback constructed here. */
   readonly registry: PermissionRegistry;
   readonly store: AuthorizationStore;
 }
 
 export interface CreateApiAppOptions {
   readonly authorization: CreateApiAppAuthorizationOptions;
+  /** The started module runtime's published, immutable route snapshot — always the caller-started
+   * runtime's exact `routes` (`startDiscoveredModuleRuntime`, `apps/api/src/server.ts`), mounted in
+   * publication order under `/api/v1/modules/<module-id>`. Required rather than defaulted so a
+   * caller not exercising modules must say so explicitly (an empty frozen array), never rely on an
+   * implicit fallback. */
+  readonly moduleRoutes: readonly RegisteredModuleHttpRoute[];
   readonly runtime: EkklesiaIdentityRuntime;
   /** Exact allowed browser origins. Never a wildcard; combined with `credentials: true`, only an
    * exact, reflected match is ever returned in `Access-Control-Allow-Origin`. Also the trusted set
-   * `requireTrustedOrigin` checks for grant-mutation routes — there is no second, competing origin
-   * configuration. */
+   * `requireTrustedOrigin` checks for grant- and module-route-mutation routes — there is no second,
+   * competing origin configuration. */
   readonly trustedOrigins: readonly string[];
 }
 
@@ -36,9 +43,14 @@ function sanitizedErrorResponse(c: Context, error: unknown, status: 500 | 503) {
 }
 
 /**
- * Pure Hono application factory: no I/O, no environment reads, no process side effects. Suitable
- * for unit and integration tests via `app.fetch` directly, with a fully injected identity runtime
- * and authorization evaluator/store standing in for real Better Auth/PostgreSQL where appropriate.
+ * Pure Hono application factory: no I/O, no environment reads, no process side effects, and it
+ * never invokes a module route handler while composing routes. Suitable for unit and integration
+ * tests via `app.fetch` directly, with a fully injected identity runtime and authorization
+ * evaluator/store standing in for real Better Auth/PostgreSQL where appropriate. Synchronously
+ * throws `ModuleRouteConfigurationError` (`./module-http-routes.js`) if `moduleRoutes` and
+ * `authorization.registry` are inconsistent — a route naming a permission the registry does not
+ * register, which should never happen since both derive from the same discovered inventory, but is
+ * checked explicitly rather than silently mounting an unenforceable route.
  */
 export function createApiApp(options: CreateApiAppOptions): Hono {
   const { runtime } = options;
@@ -48,7 +60,7 @@ export function createApiApp(options: CreateApiAppOptions): Hono {
 
   const corsMiddleware = cors({
     allowHeaders: ["Content-Type"],
-    allowMethods: ["GET", "POST", "OPTIONS"],
+    allowMethods: ["GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"],
     credentials: true,
     maxAge: 600,
     origin: (origin) => (origin && allowedOrigins.has(origin) ? origin : undefined),
@@ -91,6 +103,13 @@ export function createApiApp(options: CreateApiAppOptions): Hono {
     }),
   );
 
+  mountModuleHttpRoutes(app, options.moduleRoutes, {
+    evaluator: options.authorization.evaluator,
+    registry: options.authorization.registry,
+    runtime,
+    trustedOrigins: allowedOrigins,
+  });
+
   app.notFound((c) => {
     c.header("Cache-Control", "no-store");
     return c.json({ code: "NOT_FOUND" }, 404);
diff --git a/apps/api/src/module-http-routes.ts b/apps/api/src/module-http-routes.ts
new file mode 100644
index 0000000..a73a165
--- /dev/null
+++ b/apps/api/src/module-http-routes.ts
@@ -0,0 +1,153 @@
+import type {
+  ModuleId,
+  ModuleRouteHandlerContext,
+  RegisteredModuleHttpRoute,
+} from "@ekklesia/contracts";
+import type { Context, Hono } from "hono";
+import {
+  type AuthorizationMiddlewareOptions,
+  getAuthorizedPrincipal,
+  requirePermission,
+  requireTrustedOrigin,
+} from "./authorization-middleware.js";
+
+const MODULE_ROUTE_PREFIX = "/api/v1/modules";
+const STATE_CHANGING_METHODS: ReadonlySet<string> = new Set(["DELETE", "PATCH", "POST", "PUT"]);
+const STRIPPED_CORS_RESPONSE_HEADERS = [
+  "access-control-allow-credentials",
+  "access-control-allow-headers",
+  "access-control-allow-methods",
+  "access-control-allow-origin",
+  "access-control-expose-headers",
+  "access-control-max-age",
+];
+
+export interface ModuleHttpRoutesOptions extends AuthorizationMiddlewareOptions {
+  readonly trustedOrigins: ReadonlySet<string>;
+}
+
+/** Never carries the offending permission id, route path, module id, or any other configuration
+ * detail — a forged or inconsistent route snapshot is a startup-time composition bug, not
+ * something to describe in detail to whatever eventually logs it. */
+export class ModuleRouteConfigurationError extends Error {
+  constructor() {
+    super("A published module HTTP route references a permission that is not registered.");
+    this.name = "ModuleRouteConfigurationError";
+    this.stack = `${this.name}: ${this.message}`;
+    Object.freeze(this);
+  }
+}
+
+/** "/" is the module's own root and maps to the bare module prefix, never a required trailing
+ * slash; every other local path appends directly. Root and non-root therefore never collide, and
+ * `/api/v1/modules/<module-id>/` (the root path with a trailing slash) is never produced here. */
+function moduleRoutePath(moduleId: ModuleId, routePath: string): string {
+  return routePath === "/"
+    ? `${MODULE_ROUTE_PREFIX}/${moduleId}`
+    : `${MODULE_ROUTE_PREFIX}/${moduleId}${routePath}`;
+}
+
+function sanitizedModuleHandlerFailure(c: Context): Response {
+  c.header("Cache-Control", "no-store");
+  return c.json({ code: "MODULE_HANDLER_FAILED" }, 500);
+}
+
+/**
+ * The platform owns CORS and caching for every module route: strips any CORS-control header a
+ * handler set (defense in depth — the outer `cors()` middleware already computes the authoritative
+ * values for the actual response) and forces `Cache-Control: no-store` plus a `Vary` that always
+ * includes `Origin` and `Cookie`, since even a public-baseline handler receives an authorized
+ * principal and may personalize its response. A separate cache-policy contract is future work;
+ * this is the conservative default until then. A module's own legitimate `Vary` values (if any)
+ * are preserved alongside the forced ones.
+ */
+function sanitizeModuleResponse(response: Response): Response {
+  const headers = new Headers(response.headers);
+  for (const headerName of STRIPPED_CORS_RESPONSE_HEADERS) {
+    headers.delete(headerName);
+  }
+  headers.set("Cache-Control", "no-store");
+  const varyValues = new Set(
+    (headers.get("Vary") ?? "")
+      .split(",")
+      .map((value) => value.trim())
+      .filter((value) => value.length > 0),
+  );
+  varyValues.add("Origin");
+  varyValues.add("Cookie");
+  headers.set("Vary", [...varyValues].join(", "));
+  return new Response(response.body, {
+    headers,
+    status: response.status,
+    statusText: response.statusText,
+  });
+}
+
+/**
+ * Mounts `StartedModuleRuntime`'s published, immutable route snapshot into `app`, in publication
+ * order — never sorted or mutated, and never invoking a handler while mounting. Every route is
+ * protected by the exact same `requirePermission` middleware Core's own routes use, with
+ * `route.permission` as the only permission id ever consulted and its baseline coming exclusively
+ * from `options.registry`; a state-changing method (`POST`/`PUT`/`PATCH`/`DELETE`) additionally
+ * requires `requireTrustedOrigin` before authorization ever runs. `GET` inherits Hono's own
+ * implicit `HEAD` handling, which re-enters this exact same middleware chain and strips the
+ * response body afterward — there is no separate `HEAD` registration or permission path.
+ * `route.handler` is invoked only after authorization succeeds, with the raw Fetch `Request` and a
+ * frozen context — never a Hono `Context`, database, store, or configuration.
+ *
+ * Because the routes and registry both derive from the same discovered inventory
+ * (`prepareStartupModuleInventory`), every registered route permission should already be
+ * registered; this loop still checks that invariant explicitly and throws
+ * `ModuleRouteConfigurationError` before mounting anything further if it ever does not hold, so a
+ * forged or hand-built route snapshot fails app construction instead of silently mounting an
+ * unenforceable route. `requirePermission`'s own per-request registry lookup remains the live,
+ * defense-in-depth enforcement regardless.
+ */
+export function mountModuleHttpRoutes(
+  app: Hono,
+  routes: readonly RegisteredModuleHttpRoute[],
+  options: ModuleHttpRoutesOptions,
+): void {
+  const middlewareOptions: AuthorizationMiddlewareOptions = {
+    evaluator: options.evaluator,
+    registry: options.registry,
+    runtime: options.runtime,
+  };
+  const requireOrigin = requireTrustedOrigin(options.trustedOrigins);
+
+  for (const route of routes) {
+    if (!options.registry.has(route.permission)) {
+      throw new ModuleRouteConfigurationError();
+    }
+
+    const requireRoutePermission = requirePermission(middlewareOptions, route.permission);
+    const path = moduleRoutePath(route.moduleId, route.path);
+    const finalHandler = async (c: Context): Promise<Response> => {
+      const context: ModuleRouteHandlerContext = Object.freeze({
+        moduleId: route.moduleId,
+        params: Object.freeze({ ...c.req.param() }),
+        principal: getAuthorizedPrincipal(c),
+      });
+
+      let response: Response;
+      try {
+        response = await route.handler(c.req.raw, context);
+      } catch {
+        return sanitizedModuleHandlerFailure(c);
+      }
+      if (!(response instanceof Response)) {
+        return sanitizedModuleHandlerFailure(c);
+      }
+      return sanitizeModuleResponse(response);
+    };
+
+    // Hono's `on()` overloads resolve by literal call arity, not by the runtime length of a spread
+    // array — each branch below is therefore a distinct, fixed-arity call rather than one call
+    // spreading a variable-length handlers array.
+    if (STATE_CHANGING_METHODS.has(route.method)) {
+      app.on(route.method, path, requireOrigin, requireRoutePermission, finalHandler);
+    } else {
+      app.on(route.method, path, requireRoutePermission, finalHandler);
+    }
+  }
+}
diff --git a/apps/api/src/platform-permissions.ts b/apps/api/src/platform-permissions.ts
index 707a38e..dd57ca8 100644
--- a/apps/api/src/platform-permissions.ts
+++ b/apps/api/src/platform-permissions.ts
@@ -54,7 +54,7 @@ async function readPackageVersion(packagePath: string): Promise<string> {
   return packageData.version;
 }
 
-export interface ComposeStartupPermissionRegistryOptions {
+export interface PrepareStartupModuleInventoryOptions {
   /** Test-only escape hatch: overrides the directory module discovery scans for installed
    * modules. Never set by the executable entry point — production always discovers the real
    * repository's `modules/` directory. Platform and Module SDK versions are always read from the
@@ -62,7 +62,8 @@ export interface ComposeStartupPermissionRegistryOptions {
   readonly modulesDirectoryOverride?: string;
   /** Test-only escape hatch: supplies an already-discovered module list directly, skipping the
    * filesystem discovery step entirely, while still running the real `composePlatformPermissionRegistry`
-   * on it. Exists because a genuine exact permission-id collision between two modules is
+   * on it — and, if startup progresses that far, driving module runtime startup with this exact
+   * list too. Exists because a genuine exact permission-id collision between two modules is
    * unreachable through real discovery: module ids are unique (discovery itself rejects a
    * duplicate) and every permission id is namespaced by its own module's id, so no two
    * really-discovered modules can ever contribute the same permission id. Proving
@@ -76,18 +77,35 @@ export interface ComposeStartupPermissionRegistryOptions {
   readonly discoveredModulesOverride?: readonly DiscoveredModule[];
 }
 
+export type ComposeStartupPermissionRegistryOptions = PrepareStartupModuleInventoryOptions;
+
+export interface StartupModuleInventory {
+  /** The exact discovered-module list — in discovery order — permission composition ran against.
+   * Production startup (`apps/api/src/server.ts`) passes this same list to
+   * `startDiscoveredModuleRuntime` rather than letting the module runtime rediscover modules a
+   * second time. */
+  readonly modules: readonly DiscoveredModule[];
+  readonly permissionRegistry: PermissionRegistry;
+}
+
 /**
- * Discovers every installed module's manifest and composes the one immutable platform permission
- * registry (Core's own declarations plus every module's) — the production source of truth
- * `apps/api` enforces every request against. Only manifests are read; no module server entrypoint
- * is imported or executed, and no module lifecycle hook runs. Read the platform and Module SDK
- * versions only when this function actually executes, never at import time.
+ * Discovers every installed module's manifest exactly once and composes the one immutable platform
+ * permission registry (Core's own declarations plus every module's) from that exact discovered
+ * list — the production source of truth `apps/api` enforces every request against, and the exact
+ * module inventory `startDiscoveredModuleRuntime` starts from. Only manifests are read here; no
+ * module server entrypoint is imported or executed, and no module lifecycle hook runs. Read the
+ * platform and Module SDK versions only when this function actually executes, never at import
+ * time.
  */
-export async function composeStartupPermissionRegistry(
-  options: ComposeStartupPermissionRegistryOptions = {},
-): Promise<PermissionRegistry> {
+export async function prepareStartupModuleInventory(
+  options: PrepareStartupModuleInventoryOptions = {},
+): Promise<StartupModuleInventory> {
   if (options.discoveredModulesOverride) {
-    return composePlatformPermissionRegistry(options.discoveredModulesOverride);
+    const modules = options.discoveredModulesOverride;
+    return Object.freeze({
+      modules,
+      permissionRegistry: composePlatformPermissionRegistry(modules),
+    });
   }
 
   const repositoryRoot = resolveRepositoryRoot();
@@ -102,5 +120,24 @@ export async function composeStartupPermissionRegistry(
     platformVersion,
   });
 
-  return composePlatformPermissionRegistry(modules);
+  return Object.freeze({
+    modules,
+    permissionRegistry: composePlatformPermissionRegistry(modules),
+  });
+}
+
+/**
+ * Compatible wrapper for callers — currently only existing tests — that need this package's
+ * composed registry without the discovered module list itself. (Doctor and `modules:validate` are
+ * Core-owned and never call into `apps/api` at all; they call Core's own
+ * `composePlatformPermissionRegistry` directly over their own already-discovered module list.)
+ * Production `startApi` does not call this wrapper: it calls `prepareStartupModuleInventory`
+ * directly so it can hand the exact same discovered list to `startDiscoveredModuleRuntime`, rather
+ * than discarding it here and rediscovering modules a second time for runtime startup.
+ */
+export async function composeStartupPermissionRegistry(
+  options: ComposeStartupPermissionRegistryOptions = {},
+): Promise<PermissionRegistry> {
+  const inventory = await prepareStartupModuleInventory(options);
+  return inventory.permissionRegistry;
 }
diff --git a/apps/api/src/server.ts b/apps/api/src/server.ts
index 754df1b..59ef64e 100644
--- a/apps/api/src/server.ts
+++ b/apps/api/src/server.ts
@@ -5,13 +5,17 @@ import {
   createAuthorizationStore,
 } from "@ekklesia/core/authorization";
 import { createIdentityRuntime, type IdentityRateLimitOverride } from "@ekklesia/core/identity";
-import type { DiscoveredModule } from "@ekklesia/core/modules";
+import {
+  type DiscoveredModule,
+  type StartedModuleRuntime,
+  startDiscoveredModuleRuntime,
+} from "@ekklesia/core/modules";
 import { serve, type ServerType } from "@hono/node-server";
 import type { Hono } from "hono";
 import { createApiApp } from "./app.js";
 import { type ApiRuntimeConfig, createApiRuntimeConfig } from "./config.js";
 import { type ApiDatabaseHandle, createApiDatabase } from "./database.js";
-import { composeStartupPermissionRegistry } from "./platform-permissions.js";
+import { prepareStartupModuleInventory } from "./platform-permissions.js";
 
 const connectionTimeoutMs = 10_000;
 const operationTimeoutMs = 10_000;
@@ -26,12 +30,13 @@ export interface StartApiOptions {
   /** Test-only escape hatch: never set by the executable entry point. See
    * `IdentityRateLimitOverride` for why production must leave this unset. */
   readonly rateLimitOverride?: IdentityRateLimitOverride;
-  /** Test-only escape hatch: overrides the directory permission-composition module discovery
-   * scans. Never set by the executable entry point. See `composeStartupPermissionRegistry`. */
+  /** Test-only escape hatch: overrides the directory module discovery scans. Never set by the
+   * executable entry point. See `prepareStartupModuleInventory`. */
   readonly modulesDirectoryOverride?: string;
-  /** Test-only escape hatch: supplies an already-discovered module list directly to permission
-   * composition, skipping filesystem discovery entirely. Never set by the executable entry
-   * point. See `composeStartupPermissionRegistry`. */
+  /** Test-only escape hatch: supplies an already-discovered module list directly, skipping
+   * filesystem discovery entirely — this exact list drives both permission composition and module
+   * runtime startup. Never set by the executable entry point. See
+   * `prepareStartupModuleInventory`. */
   readonly discoveredModulesOverride?: readonly DiscoveredModule[];
 }
 
@@ -44,6 +49,17 @@ async function safeCloseDatabase(handle: ApiDatabaseHandle): Promise<void> {
   }
 }
 
+/** Same swallow-on-cleanup-path rule as `safeCloseDatabase`, used only while unwinding a startup
+ * failure that already occurred after the module runtime started — never during normal shutdown,
+ * where a module stop failure remains an observable result instead (see `startApi`'s `shutdown`). */
+async function safeStopModuleRuntime(moduleRuntime: StartedModuleRuntime): Promise<void> {
+  try {
+    await moduleRuntime.stop();
+  } catch {
+    // See safeCloseDatabase: never mask the startup failure already propagating.
+  }
+}
+
 function bindServer(app: Hono, host: string, port: number): Promise<ServerType> {
   return new Promise((resolve, reject) => {
     let settled = false;
@@ -63,25 +79,36 @@ function bindServer(app: Hono, host: string, port: number): Promise<ServerType>
 }
 
 /**
- * Explicit runtime composition, in a fixed order: discover every installed module's manifest and
- * compose the one immutable platform permission registry from Core's own declarations plus every
- * module's (`./platform-permissions.js`); only then construct the one shared PostgreSQL pool
- * (identity and authorization each get a typed Drizzle view over it — see `./database.js`), the
- * Core identity runtime, the Core authorization store and evaluator, and the Hono application;
- * finally start the Node HTTP server. Permission composition happens before any pool, Better
- * Auth instance, or HTTP server exists, so a discovery or composition failure — an invalid
+ * Explicit runtime composition, in a fixed order:
+ *
+ * 1. Discover every installed module's manifest exactly once and compose the one immutable
+ *    platform permission registry from Core's own declarations plus every module's
+ *    (`prepareStartupModuleInventory`, `./platform-permissions.js`).
+ * 2. Construct the one shared PostgreSQL pool (identity and authorization each get a typed
+ *    Drizzle view over it — see `./database.js`).
+ * 3. Construct the Core identity runtime, authorization store, and evaluator.
+ * 4. Start the module runtime from that exact same discovered inventory
+ *    (`startDiscoveredModuleRuntime`) — never rediscovering modules a second time.
+ * 5. Create the Hono application, mounting the started module runtime's published routes.
+ * 6. Bind the Node HTTP server.
+ *
+ * Discovery and permission composition happen before any pool, Better Auth instance, module
+ * entrypoint import, or HTTP server exists, so a discovery or composition failure — an invalid
  * manifest, a dependency-graph problem, a module claiming the reserved `core.*` permission
  * namespace, or a duplicate permission declaration — leaves nothing to close: it propagates
- * directly, and startup never falls back to a Core-only registry. Returns a handle with an
- * idempotent `shutdown()` so both the executable entry point and tests can stop the server and
- * close the shared pool deterministically. Never applies migrations or generates schema — the
- * database must already be migrated through `pnpm migrations:apply`.
+ * directly, and startup never falls back to a Core-only registry. Core infrastructure (the pool,
+ * identity, authorization) exists before any executable module lifecycle code runs, and every
+ * module route is published only after the entire module runtime has registered and started
+ * successfully, so no request can ever reach a module before every module has started. Returns a
+ * handle with an idempotent `shutdown()` so both the executable entry point and tests can stop the
+ * server, the module runtime, and the shared pool deterministically. Never applies migrations or
+ * generates schema — the database must already be migrated through `pnpm migrations:apply`.
  */
 export async function startApi(
   config: ApiRuntimeConfig,
   options: StartApiOptions = {},
 ): Promise<RunningApi> {
-  const permissionRegistry = await composeStartupPermissionRegistry({
+  const inventory = await prepareStartupModuleInventory({
     ...(options.modulesDirectoryOverride === undefined
       ? {}
       : { modulesDirectoryOverride: options.modulesDirectoryOverride }),
@@ -114,16 +141,40 @@ export async function startApi(
     platformOwners: authorizationStore,
   });
 
-  const app = createApiApp({
-    authorization: { evaluator, registry: permissionRegistry, store: authorizationStore },
-    runtime,
-    trustedOrigins: config.identity.trustedOrigins,
-  });
+  // Module load/register/start failures use Core's own existing rollback (already-started
+  // modules are stopped, in reverse order, before this rejects) — there is no separate runtime
+  // handle to stop here, only the pool this failure leaves open.
+  let moduleRuntime: StartedModuleRuntime;
+  try {
+    moduleRuntime = await startDiscoveredModuleRuntime(inventory.modules);
+  } catch (error) {
+    await safeCloseDatabase(databaseHandle);
+    throw error;
+  }
+
+  let app: Hono;
+  try {
+    app = createApiApp({
+      authorization: {
+        evaluator,
+        registry: inventory.permissionRegistry,
+        store: authorizationStore,
+      },
+      moduleRoutes: moduleRuntime.routes,
+      runtime,
+      trustedOrigins: config.identity.trustedOrigins,
+    });
+  } catch (error) {
+    await safeStopModuleRuntime(moduleRuntime);
+    await safeCloseDatabase(databaseHandle);
+    throw error;
+  }
 
   let server: ServerType;
   try {
     server = await bindServer(app, config.host, config.port);
   } catch (error) {
+    await safeStopModuleRuntime(moduleRuntime);
     await safeCloseDatabase(databaseHandle);
     throw error;
   }
@@ -133,7 +184,12 @@ export async function startApi(
   // would previously get an already-resolved `undefined` immediately, before the listener had
   // actually drained or the pool had actually closed. Storing the promise itself means every
   // caller — concurrent or sequential — awaits the exact same drain-then-close operation and
-  // observes it complete (or fail) exactly once.
+  // observes it complete (or fail) exactly once. Order matters: the HTTP listener is drained and
+  // closed first so no new or in-flight request can reach a module handler while the module
+  // runtime is stopping, then the module runtime stops, then the shared pool closes. Unlike the
+  // startup-cleanup paths above, a module-stop failure here is not swallowed — it is a genuine
+  // shutdown result a caller should observe — but database cleanup still always runs first, so a
+  // stop failure never leaves the pool open.
   let shutdownPromise: Promise<void> | undefined;
   const shutdown = (): Promise<void> => {
     if (!shutdownPromise) {
@@ -141,7 +197,16 @@ export async function startApi(
         await new Promise<void>((resolve) => {
           server.close(() => resolve());
         });
+        let moduleStopError: unknown;
+        try {
+          await moduleRuntime.stop();
+        } catch (error) {
+          moduleStopError = error;
+        }
         await safeCloseDatabase(databaseHandle);
+        if (moduleStopError) {
+          throw moduleStopError;
+        }
       })();
     }
     return shutdownPromise;
diff --git a/apps/api/tests/api-http.integration.ts b/apps/api/tests/api-http.integration.ts
index 902ae1b..c25af5a 100644
--- a/apps/api/tests/api-http.integration.ts
+++ b/apps/api/tests/api-http.integration.ts
@@ -200,6 +200,7 @@ async function applyCoreMigrations(url: string): Promise<void> {
 }
 
 const trackedModulesDirectories: string[] = [];
+const eventSymbols: symbol[] = [];
 
 async function createFixtureModulesDirectory(): Promise<string> {
   const directory = await mkdtemp(path.join(tmpdir(), "ekklesia-api-installed-modules-"));
@@ -207,13 +208,31 @@ async function createFixtureModulesDirectory(): Promise<string> {
   return directory;
 }
 
-/** Writes a minimal, structurally valid module fixture straight to disk — real discovery and
- * composition run against it, nothing hand-built. The server entrypoint throws immediately if
- * ever imported/executed, so a scenario that completes without that throw firing is direct
- * evidence permission composition and Doctor never ran module lifecycle code. */
+/** A dynamically imported module fixture cannot close over this test file's local variables, so
+ * lifecycle markers cross that boundary through a `globalThis` symbol instead (same technique as
+ * `core/tests/module-runtime.test.ts`). */
+function createEventRecorder(): { events: string[]; expression: string } {
+  const key = `ekklesia.api.integration.test.${eventSymbols.length}.${Date.now()}.${Math.random()}`;
+  const symbol = Symbol.for(key);
+  const events: string[] = [];
+  (globalThis as unknown as Record<PropertyKey, unknown>)[symbol] = events;
+  eventSymbols.push(symbol);
+  return { events, expression: `globalThis[Symbol.for(${JSON.stringify(key)})]` };
+}
+
+/** Writes a minimal, structurally valid module fixture straight to disk — real discovery,
+ * composition, and (where a scenario actually starts the API) real module runtime execution all
+ * run against it, nothing hand-built. Register/start/stop push markers onto `recorder.events`
+ * instead of throwing, so both "Doctor/composition never executed this" (an empty recorder) and
+ * "startApi actually imported, registered, and started this" (a populated recorder) can be proven
+ * against the exact same fixture. When declared with the `calendar.events.read` permission, the
+ * module also registers a restricted `GET /events/:eventId` route and a restricted, state-changing
+ * `POST /events` route against that same permission, so the full HTTP mounting/enforcement chain
+ * can be exercised live. */
 async function createFixtureModule(
   modulesDirectory: string,
   id: string,
+  recorder: { expression: string },
   manifestOverrides: Record<string, unknown> = {},
 ): Promise<void> {
   const moduleDirectory = path.join(modulesDirectory, id);
@@ -227,6 +246,9 @@ async function createFixtureModule(
     entrypoints: { server: "./dist/server/index.js" },
     ...manifestOverrides,
   };
+  const declaresCalendarRead = (manifest.permissions as ReadonlyArray<{ id: string }>).some(
+    (declaration) => declaration.id === "calendar.events.read",
+  );
   await mkdir(path.join(moduleDirectory, "dist/server"), { recursive: true });
   await Promise.all([
     writeFile(
@@ -241,7 +263,39 @@ async function createFixtureModule(
     writeFile(path.join(moduleDirectory, "ekklesia.module.json"), JSON.stringify(manifest)),
     writeFile(
       path.join(moduleDirectory, "dist/server/index.js"),
-      'throw new Error("permission composition and Doctor must never execute a module server entrypoint");',
+      `export default {
+        id: ${JSON.stringify(id)},
+        version: "0.1.0",
+        register({ http }) {
+          ${recorder.expression}.push(${JSON.stringify(`${id}:register`)});
+          ${
+            declaresCalendarRead
+              ? `http.route({
+                  method: "GET",
+                  path: "/events/:eventId",
+                  permission: "calendar.events.read",
+                  async handler(request, context) {
+                    return Response.json({ eventId: context.params.eventId, principal: context.principal });
+                  },
+                });
+                http.route({
+                  method: "POST",
+                  path: "/events",
+                  permission: "calendar.events.read",
+                  async handler(request, context) {
+                    return Response.json({ created: true, principal: context.principal }, { status: 201 });
+                  },
+                });`
+              : ""
+          }
+        },
+        start() {
+          ${recorder.expression}.push(${JSON.stringify(`${id}:start`)});
+        },
+        stop() {
+          ${recorder.expression}.push(${JSON.stringify(`${id}:stop`)});
+        },
+      };`,
     ),
   ]);
 }
@@ -253,6 +307,10 @@ afterAll(async () => {
   for (const directory of trackedModulesDirectories.splice(0)) {
     await rm(directory, { recursive: true, force: true }).catch(() => undefined);
   }
+  const globalValues = globalThis as unknown as Record<PropertyKey, unknown>;
+  for (const symbol of eventSymbols.splice(0)) {
+    delete globalValues[symbol];
+  }
 });
 
 const identityBaseUrl = "https://identity.example.test";
@@ -1222,10 +1280,11 @@ describe.sequential("live API — installed module permission end-to-end", () =>
   const password = "correct horse battery staple";
   const modulePermission = "calendar.events.read";
   const absentPermission = "scheduler.jobs.read";
+  const recorder = createEventRecorder();
 
   it("recognizes a real installed module and passes permission composition in Doctor, without executing its server entrypoint", async () => {
     modulesDirectory = await createFixtureModulesDirectory();
-    await createFixtureModule(modulesDirectory, "calendar", {
+    await createFixtureModule(modulesDirectory, "calendar", recorder, {
       permissions: [
         {
           baseline: "restricted",
@@ -1257,14 +1316,21 @@ describe.sequential("live API — installed module permission end-to-end", () =>
       details: ["2 permissions registered"],
       status: "pass",
     });
+    // Doctor and permission composition read only the manifest — the fixture's register/start
+    // markers must remain entirely unset.
+    expect(recorder.events).toEqual([]);
   });
 
-  it("starts a freshly migrated API that discovers the fixture module and signs up its eventual owner", async () => {
+  it("starts a freshly migrated API that discovers the fixture module, imports and starts its runtime exactly once, and mounts its route", async () => {
     database = await createDisposableDatabase("authz_module");
     await applyCoreMigrations(database.url);
     running = await startMigratedApi(database.url, modulesDirectory);
     origin = apiOrigin(running);
 
+    // Unlike Doctor above, a successful production startup does deliberately import, register,
+    // and start the module's runtime — exactly once each.
+    expect(recorder.events).toEqual(["calendar:register", "calendar:start"]);
+
     const ownerSignUp = await signUp(origin, ownerEmail, password);
     ownerUserId = ownerSignUp.body.user.id;
     const ownerSignIn = await signIn(origin, ownerEmail, password);
@@ -1316,6 +1382,56 @@ describe.sequential("live API — installed module permission end-to-end", () =>
     }
   });
 
+  it("denies the module's own mounted route to an anonymous caller, then serves it to the newly granted owner with the decoded path parameter and authenticated principal", async () => {
+    const anonymousResponse = await fetch(`${origin}/api/v1/modules/calendar/events/evt-42`);
+    expect(anonymousResponse.status).toBe(403);
+    expect(await anonymousResponse.json()).toEqual({ code: "AUTHORIZATION_DENIED" });
+
+    const grantedResponse = await fetch(`${origin}/api/v1/modules/calendar/events/evt-42`, {
+      headers: { cookie: ownerCookie },
+    });
+    expect(grantedResponse.status).toBe(200);
+    const body = (await grantedResponse.json()) as {
+      eventId: string;
+      principal: { kind: string; userId: string };
+    };
+    expect(body.eventId).toBe("evt-42");
+    expect(body.principal).toEqual({ kind: "authenticated", userId: ownerUserId });
+  });
+
+  it("requires a trusted Origin for the module's own state-changing route, exactly like the platform's own mutation routes", async () => {
+    const noOriginResponse = await fetch(`${origin}/api/v1/modules/calendar/events`, {
+      body: JSON.stringify({}),
+      headers: { "content-type": "application/json", cookie: ownerCookie },
+      method: "POST",
+    });
+    expect(noOriginResponse.status).toBe(403);
+    expect(await noOriginResponse.json()).toEqual({ code: "UNTRUSTED_ORIGIN" });
+
+    const untrustedResponse = await fetch(`${origin}/api/v1/modules/calendar/events`, {
+      body: JSON.stringify({}),
+      headers: {
+        "content-type": "application/json",
+        cookie: ownerCookie,
+        origin: untrustedOrigin,
+      },
+      method: "POST",
+    });
+    expect(untrustedResponse.status).toBe(403);
+
+    const trustedResponse = await fetch(`${origin}/api/v1/modules/calendar/events`, {
+      body: JSON.stringify({}),
+      headers: {
+        "content-type": "application/json",
+        cookie: ownerCookie,
+        origin: dashboardOrigin,
+      },
+      method: "POST",
+    });
+    expect(trustedResponse.status).toBe(201);
+    expect(await trustedResponse.json()).toMatchObject({ created: true });
+  });
+
   it("rejects a well-formed permission absent from the composed registry, writing no grant or audit row", async () => {
     const admin = await openAdministrativeClient(database.url);
     try {
@@ -1355,15 +1471,24 @@ describe.sequential("live API — installed module permission end-to-end", () =>
     }
   });
 
-  it("shuts down cleanly, then restarting with the module absent rejects new grants for its former permission while the historical grant remains listable", async () => {
+  it("shuts down cleanly, then restarting with the module absent rejects new grants for its former permission, returns NOT_FOUND for its former route, while the historical grant remains listable", async () => {
     await running.shutdown();
     const remainingConnections = await activeConnectionCount(database.name);
     expect(remainingConnections).toBe(0);
+    // Exactly one stop, matching the exactly-one register/start already asserted above.
+    expect(recorder.events.filter((event) => event === "calendar:stop")).toHaveLength(1);
 
     const emptyModulesDirectory = await createFixtureModulesDirectory();
     running = await startMigratedApi(database.url, emptyModulesDirectory);
     origin = apiOrigin(running);
 
+    // The module's own route is unmounted along with the module itself.
+    const removedRouteResponse = await fetch(`${origin}/api/v1/modules/calendar/events/evt-42`, {
+      headers: { cookie: ownerCookie },
+    });
+    expect(removedRouteResponse.status).toBe(404);
+    expect(await removedRouteResponse.json()).toEqual({ code: "NOT_FOUND" });
+
     // The owner's existing session survives the restart (sessions live in the database, not the
     // process), so the same cookie proves ordinary identity behavior is unaffected here too.
     const listResponse = await fetch(`${origin}/api/v1/grants?userId=${ownerUserId}`, {
diff --git a/apps/api/tests/app.test.ts b/apps/api/tests/app.test.ts
index a7d9e27..a2bbe26 100644
--- a/apps/api/tests/app.test.ts
+++ b/apps/api/tests/app.test.ts
@@ -52,6 +52,7 @@ describe("Ekklesia API Hono application", () => {
   it("mounts Better Auth exactly under /api/auth/*", async () => {
     const runtime = fakeRuntime();
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime,
       trustedOrigins: [trustedOrigin],
@@ -67,6 +68,7 @@ describe("Ekklesia API Hono application", () => {
   it("does not route requests outside /api/auth/* to Better Auth", async () => {
     const runtime = fakeRuntime();
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime,
       trustedOrigins: [trustedOrigin],
@@ -83,6 +85,7 @@ describe("Ekklesia API Hono application", () => {
       resolvePrincipal: vi.fn().mockResolvedValue(ANONYMOUS_PRINCIPAL),
     });
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime,
       trustedOrigins: [trustedOrigin],
@@ -101,6 +104,7 @@ describe("Ekklesia API Hono application", () => {
       resolvePrincipal: vi.fn().mockResolvedValue(createAuthenticatedPrincipal("user_123")),
     });
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime,
       trustedOrigins: [trustedOrigin],
@@ -121,6 +125,7 @@ describe("Ekklesia API Hono application", () => {
         .mockRejectedValue(new IdentityRuntimeError("PRINCIPAL_RESOLUTION_FAILED")),
     });
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime,
       trustedOrigins: [trustedOrigin],
@@ -138,6 +143,7 @@ describe("Ekklesia API Hono application", () => {
       handleAuthRequest: vi.fn().mockRejectedValue(new Error("postgresql://admin:secret@db/x")),
     });
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime,
       trustedOrigins: [trustedOrigin],
@@ -154,6 +160,7 @@ describe("Ekklesia API Hono application", () => {
 
   it("has deterministic 404 behavior for an unknown route", async () => {
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime: fakeRuntime(),
       trustedOrigins: [trustedOrigin],
@@ -167,6 +174,7 @@ describe("Ekklesia API Hono application", () => {
 
   it("reflects an allowed origin in Access-Control-Allow-Origin with credentials support", async () => {
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime: fakeRuntime(),
       trustedOrigins: [trustedOrigin],
@@ -182,6 +190,7 @@ describe("Ekklesia API Hono application", () => {
 
   it("never returns Access-Control-Allow-Origin for a disallowed origin", async () => {
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime: fakeRuntime(),
       trustedOrigins: [trustedOrigin],
@@ -196,6 +205,7 @@ describe("Ekklesia API Hono application", () => {
 
   it("supports requests with no Origin header at all (native/server clients)", async () => {
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime: fakeRuntime(),
       trustedOrigins: [trustedOrigin],
@@ -208,6 +218,7 @@ describe("Ekklesia API Hono application", () => {
 
   it("handles preflight OPTIONS requests deterministically for an allowed origin", async () => {
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime: fakeRuntime(),
       trustedOrigins: [trustedOrigin],
@@ -227,6 +238,7 @@ describe("Ekklesia API Hono application", () => {
 
   it("never wildcards Access-Control-Allow-Origin", async () => {
     const app = createApiApp({
+      moduleRoutes: Object.freeze([]),
       authorization: fakeAuthorization({}),
       runtime: fakeRuntime(),
       trustedOrigins: [trustedOrigin],
@@ -249,6 +261,7 @@ describe("Ekklesia API Hono application", () => {
     it("mounts the v1 grants routes under /api/v1/grants", async () => {
       const evaluatorAuthorize = vi.fn().mockResolvedValue({ allowed: false });
       const app = createApiApp({
+        moduleRoutes: Object.freeze([]),
         authorization: fakeAuthorization({ evaluator: { authorize: evaluatorAuthorize } }),
         runtime: fakeRuntime(),
         trustedOrigins: [trustedOrigin],
@@ -274,6 +287,7 @@ describe("Ekklesia API Hono application", () => {
         has: () => false,
       };
       const app = createApiApp({
+        moduleRoutes: Object.freeze([]),
         authorization: fakeAuthorization({
           evaluator: { authorize: evaluatorAuthorize },
           registry: emptyRegistry,
@@ -290,6 +304,7 @@ describe("Ekklesia API Hono application", () => {
 
     it("applies the same CORS policy to /api/v1/grants as the rest of /api/v1/*", async () => {
       const app = createApiApp({
+        moduleRoutes: Object.freeze([]),
         authorization: fakeAuthorization({}),
         runtime: fakeRuntime(),
         trustedOrigins: [trustedOrigin],
diff --git a/apps/api/tests/lifecycle.test.ts b/apps/api/tests/lifecycle.test.ts
index c58cdae..b404456 100644
--- a/apps/api/tests/lifecycle.test.ts
+++ b/apps/api/tests/lifecycle.test.ts
@@ -13,6 +13,13 @@ vi.mock("pg", () => ({ Pool: poolConstructor }));
 vi.mock("better-auth", () => ({ betterAuth: betterAuthMock }));
 vi.mock("better-auth/adapters/drizzle", () => ({ drizzleAdapter: drizzleAdapterMock }));
 vi.mock("@hono/node-server", () => ({ serve: serveMock }));
+// Wraps the real `createApiApp` in a spy rather than replacing it, so every existing test still
+// gets the real Hono application; only the one test that deliberately forces an app-construction
+// failure overrides this with `mockImplementationOnce`.
+vi.mock("../src/app.js", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("../src/app.js")>();
+  return { ...actual, createApiApp: vi.fn(actual.createApiApp) };
+});
 
 import { parseModuleManifest } from "@ekklesia/contracts";
 import {
@@ -21,6 +28,7 @@ import {
   ModulePermissionCompositionError,
 } from "@ekklesia/core/modules";
 import { PermissionRegistryError } from "@ekklesia/core/authorization";
+import { createApiApp } from "../src/app.js";
 import { createApiRuntimeConfig } from "../src/config.js";
 import { installShutdownSignalHandlers, startApi } from "../src/server.js";
 
@@ -87,6 +95,76 @@ async function createFixtureModule(
   ]);
 }
 
+const eventSymbols: symbol[] = [];
+
+/** Same technique as `core/tests/module-runtime.test.ts`: a dynamically imported module fixture
+ * cannot close over this test file's local variables, so lifecycle events cross that boundary
+ * through a `globalThis` symbol instead. Returns the same `events` array the fixture's generated
+ * source pushes into, so test code can both read it directly and push its own markers (pool
+ * close, server close) onto the identical array to observe cross-cutting shutdown order. */
+function createEventRecorder(): { events: string[]; expression: string } {
+  const key = `ekklesia.api.lifecycle.test.${eventSymbols.length}.${Date.now()}.${Math.random()}`;
+  const symbol = Symbol.for(key);
+  const events: string[] = [];
+  (globalThis as unknown as Record<PropertyKey, unknown>)[symbol] = events;
+  eventSymbols.push(symbol);
+  return { events, expression: `globalThis[Symbol.for(${JSON.stringify(key)})]` };
+}
+
+interface WorkingFixtureModuleOptions {
+  /** Declares one `GET /ping` route against `<id>.ping.read` when true. */
+  readonly withRoute?: boolean;
+  readonly registerThrows?: boolean;
+  readonly startThrows?: boolean;
+  readonly stopThrows?: boolean;
+  readonly dependencies?: Record<string, unknown>;
+}
+
+/** Writes a real, working module fixture — unlike `createFixtureModule`, this entrypoint does not
+ * throw on import; it pushes lifecycle markers onto `recorder.events` and can be told to fail at a
+ * specific hook, so tests can prove exactly what a successful (or a specifically-failing) module
+ * runtime startup actually executes and in what order, relative to pool/server construction. */
+async function createWorkingFixtureModule(
+  modulesDirectory: string,
+  id: string,
+  recorder: { expression: string },
+  options: WorkingFixtureModuleOptions = {},
+): Promise<void> {
+  const permissionId = `${id}.ping.read`;
+  await createFixtureModule(modulesDirectory, id, {
+    permissions: options.withRoute
+      ? [{ baseline: "public", description: "Ping.", id: permissionId }]
+      : [],
+    ...(options.dependencies ? { dependencies: options.dependencies } : {}),
+  });
+  const routeSource = options.withRoute
+    ? `http.route({
+        method: "GET",
+        path: "/ping",
+        permission: ${JSON.stringify(permissionId)},
+        handler: async () => new Response("pong", { status: 200 }),
+      });`
+    : "";
+  const serverSource = `export default {
+    id: ${JSON.stringify(id)},
+    version: "0.1.0",
+    register({ http }) {
+      ${recorder.expression}.push(${JSON.stringify(`${id}:register`)});
+      ${routeSource}
+      ${options.registerThrows ? 'throw new Error("register failed");' : ""}
+    },
+    start() {
+      ${recorder.expression}.push(${JSON.stringify(`${id}:start`)});
+      ${options.startThrows ? 'throw new Error("start failed");' : ""}
+    },
+    stop() {
+      ${recorder.expression}.push(${JSON.stringify(`${id}:stop`)});
+      ${options.stopThrows ? 'throw new Error("stop failed");' : ""}
+    },
+  };`;
+  await writeFile(path.join(modulesDirectory, id, "dist/server/index.js"), serverSource);
+}
+
 /** A minimal, in-memory `DiscoveredModule` double built from a real, validated manifest — used
  * only to reach `composePlatformPermissionRegistry`'s own duplicate-detection failure, which is
  * unreachable through real filesystem discovery (module ids are unique and every permission id is
@@ -518,3 +596,252 @@ describe("Ekklesia API module permission composition at startup", () => {
     expect(poolConstructor).not.toHaveBeenCalled();
   });
 });
+
+describe("Ekklesia API module runtime startup and shutdown", () => {
+  afterEach(async () => {
+    const globalValues = globalThis as unknown as Record<PropertyKey, unknown>;
+    for (const symbol of eventSymbols.splice(0)) {
+      delete globalValues[symbol];
+    }
+    await Promise.all(
+      temporaryDirectories.splice(0).map((directory) => rm(directory, { recursive: true })),
+    );
+  });
+
+  beforeEach(() => {
+    poolConstructor.mockReset();
+    betterAuthMock.mockReset();
+    drizzleAdapterMock.mockClear();
+    serveMock.mockReset();
+    vi.mocked(createApiApp).mockClear();
+  });
+
+  function mockPoolAndAuth(): { poolEnd: ReturnType<typeof vi.fn> } {
+    const poolEnd = vi.fn().mockResolvedValue(undefined);
+    poolConstructor.mockImplementation(function fakePool() {
+      return { end: poolEnd, on: vi.fn() };
+    });
+    betterAuthMock.mockReturnValue({ api: { getSession: vi.fn() }, handler: vi.fn() });
+    return { poolEnd };
+  }
+
+  it("starts the module runtime from the exact discovered inventory permission composition used, mounting routes in discovery order", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "alpha", recorder, { withRoute: true });
+    await createWorkingFixtureModule(modulesDirectory, "beta", recorder, { withRoute: true });
+    mockPoolAndAuth();
+    mockSuccessfulServe();
+
+    const running = await startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory });
+
+    expect(recorder.events).toEqual([
+      "alpha:register",
+      "beta:register",
+      "alpha:start",
+      "beta:start",
+    ]);
+    // Hono records one internal route entry per handler in a route's middleware chain, not one
+    // per logical route, so entries for the same method/path are deduplicated (preserving first-
+    // seen order) before asserting mounting order.
+    const moduleRoutePaths = [
+      ...new Set(
+        running.app.routes
+          .filter((route) => route.path.startsWith("/api/v1/modules/"))
+          .map((route) => `${route.method} ${route.path}`),
+      ),
+    ];
+    expect(moduleRoutePaths).toEqual([
+      "GET /api/v1/modules/alpha/ping",
+      "GET /api/v1/modules/beta/ping",
+    ]);
+
+    await running.shutdown();
+  });
+
+  it("closes the pool exactly once and binds no server when a module's entrypoint fails to load", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    await createFixtureModule(modulesDirectory, "broken-export");
+    await writeFile(
+      path.join(modulesDirectory, "broken-export", "dist/server/index.js"),
+      "export default { thisIsNotAValidRuntimeDefinition: true };",
+    );
+    const { poolEnd } = mockPoolAndAuth();
+
+    await expect(
+      startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory }),
+    ).rejects.toMatchObject({
+      issues: [expect.objectContaining({ code: "MODULE_RUNTIME_EXPORT_INVALID" })],
+    });
+
+    expect(poolConstructor).toHaveBeenCalledTimes(1);
+    expect(poolEnd).toHaveBeenCalledTimes(1);
+    expect(serveMock).not.toHaveBeenCalled();
+  });
+
+  it("closes the pool exactly once and binds no server when a module's register hook fails", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "register-fails", recorder, {
+      registerThrows: true,
+    });
+    const { poolEnd } = mockPoolAndAuth();
+
+    await expect(
+      startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory }),
+    ).rejects.toMatchObject({
+      issues: [expect.objectContaining({ code: "MODULE_REGISTER_FAILED" })],
+    });
+
+    expect(recorder.events).toEqual(["register-fails:register"]);
+    expect(poolConstructor).toHaveBeenCalledTimes(1);
+    expect(poolEnd).toHaveBeenCalledTimes(1);
+    expect(serveMock).not.toHaveBeenCalled();
+  });
+
+  it("closes the pool exactly once and binds no server when a module's start hook fails, preserving Core's rollback of already-started modules", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "one", recorder);
+    await createWorkingFixtureModule(modulesDirectory, "two", recorder, {
+      dependencies: { modules: { required: { one: "^0.1.0" } } },
+      startThrows: true,
+    });
+    const { poolEnd } = mockPoolAndAuth();
+
+    await expect(
+      startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory }),
+    ).rejects.toMatchObject({
+      issues: [expect.objectContaining({ code: "MODULE_START_FAILED" })],
+    });
+
+    expect(recorder.events).toEqual([
+      "one:register",
+      "two:register",
+      "one:start",
+      "two:start",
+      "one:stop",
+    ]);
+    expect(poolConstructor).toHaveBeenCalledTimes(1);
+    expect(poolEnd).toHaveBeenCalledTimes(1);
+    expect(serveMock).not.toHaveBeenCalled();
+  });
+
+  it("stops the module runtime and closes the pool, binding no server, when app construction fails", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "mounted", recorder);
+    const { poolEnd } = mockPoolAndAuth();
+    vi.mocked(createApiApp).mockImplementationOnce(() => {
+      throw new Error("forced app construction failure");
+    });
+
+    await expect(
+      startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory }),
+    ).rejects.toThrow("forced app construction failure");
+
+    expect(recorder.events).toEqual(["mounted:register", "mounted:start", "mounted:stop"]);
+    expect(poolConstructor).toHaveBeenCalledTimes(1);
+    expect(poolEnd).toHaveBeenCalledTimes(1);
+    expect(serveMock).not.toHaveBeenCalled();
+  });
+
+  it("stops the module runtime and closes the pool when the server fails to bind", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "mounted", recorder);
+    const { poolEnd } = mockPoolAndAuth();
+    mockFailingServe(new Error("EADDRINUSE"));
+
+    await expect(
+      startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory }),
+    ).rejects.toThrow();
+
+    expect(recorder.events).toEqual(["mounted:register", "mounted:start", "mounted:stop"]);
+    expect(poolConstructor).toHaveBeenCalledTimes(1);
+    expect(poolEnd).toHaveBeenCalledTimes(1);
+  });
+
+  it("drains the HTTP server, then stops the module runtime, then closes the pool, in that exact order", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "ordered", recorder);
+    poolConstructor.mockImplementation(function fakePool() {
+      return {
+        end: vi.fn(async () => {
+          recorder.events.push("pool:end");
+        }),
+        on: vi.fn(),
+      };
+    });
+    betterAuthMock.mockReturnValue({ api: { getSession: vi.fn() }, handler: vi.fn() });
+    const { server } = mockSuccessfulServe();
+    const originalClose = server.close;
+    server.close = vi.fn((callback?: () => void) => {
+      recorder.events.push("server:close");
+      return originalClose(callback);
+    });
+
+    const running = await startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory });
+    recorder.events.length = 0;
+    await running.shutdown();
+
+    expect(recorder.events).toEqual(["server:close", "ordered:stop", "pool:end"]);
+  });
+
+  it("still runs pool cleanup and lets the shutdown rejection surface when the module runtime fails to stop", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "stop-fails", recorder, {
+      stopThrows: true,
+    });
+    const { poolEnd } = mockPoolAndAuth();
+    mockSuccessfulServe();
+
+    const running = await startApi(validConfig(), { modulesDirectoryOverride: modulesDirectory });
+
+    await expect(running.shutdown()).rejects.toMatchObject({
+      issues: [expect.objectContaining({ code: "MODULE_STOP_FAILED", moduleId: "stop-fails" })],
+    });
+    expect(poolEnd).toHaveBeenCalledTimes(1);
+  });
+
+  it("keeps a direct discoveredModulesOverride driving both permission composition and module runtime startup", async () => {
+    const modulesDirectory = await createTemporaryModulesDirectory();
+    const recorder = createEventRecorder();
+    await createWorkingFixtureModule(modulesDirectory, "calendar", recorder, { withRoute: true });
+    const discovered = await (await import("@ekklesia/core/modules")).discoverModules({
+      moduleSdkVersion: "0.1.0",
+      modulesDirectory,
+      platformVersion: "0.1.0",
+    });
+    mockPoolAndAuth();
+    mockSuccessfulServe();
+
+    const running = await startApi(validConfig(), { discoveredModulesOverride: discovered });
+
+    expect(recorder.events).toEqual(["calendar:register", "calendar:start"]);
+    // Hono records one internal route entry per handler in a route's middleware chain, not one
+    // per logical route, so entries for the same method/path are deduplicated (preserving first-
+    // seen order) before asserting mounting order.
+    const moduleRoutePaths = [
+      ...new Set(
+        running.app.routes
+          .filter((route) => route.path.startsWith("/api/v1/modules/"))
+          .map((route) => `${route.method} ${route.path}`),
+      ),
+    ];
+    expect(moduleRoutePaths).toEqual(["GET /api/v1/modules/calendar/ping"]);
+
+    await running.shutdown();
+  });
+
+  it("performs no filesystem I/O, module import, pool construction, Better Auth construction, or server binding merely by importing the module-route adapter", async () => {
+    const module = await import("../src/module-http-routes.js");
+
+    expect(typeof module.mountModuleHttpRoutes).toBe("function");
+    expect(poolConstructor).not.toHaveBeenCalled();
+    expect(betterAuthMock).not.toHaveBeenCalled();
+    expect(serveMock).not.toHaveBeenCalled();
+  });
+});
diff --git a/apps/api/tests/module-http-routes.test.ts b/apps/api/tests/module-http-routes.test.ts
new file mode 100644
index 0000000..ca38c82
--- /dev/null
+++ b/apps/api/tests/module-http-routes.test.ts
@@ -0,0 +1,936 @@
+import {
+  ANONYMOUS_PRINCIPAL,
+  createAuthenticatedPrincipal,
+  type ModuleRouteHandler,
+  type ModuleRouteHandlerContext,
+  parsePermissionId,
+  type PermissionId,
+  type RegisteredModuleHttpRoute,
+} from "@ekklesia/contracts";
+import {
+  type AuthorizationEvaluator,
+  type AuthorizationStore,
+  createPermissionRegistry,
+  type PermissionRegistry,
+} from "@ekklesia/core/authorization";
+import type { EkklesiaIdentityRuntime } from "@ekklesia/core/identity";
+import { describe, expect, it, vi } from "vitest";
+import { createApiApp } from "../src/app.js";
+import { ModuleRouteConfigurationError } from "../src/module-http-routes.js";
+
+const trustedOrigin = "https://dashboard.example.test";
+const untrustedOrigin = "https://evil.example.test";
+const readPermission = parsePermissionId("calendar.events.read");
+const writePermission = parsePermissionId("calendar.events.write");
+
+function fakeRuntime(overrides: Partial<EkklesiaIdentityRuntime> = {}): EkklesiaIdentityRuntime {
+  return {
+    handleAuthRequest: vi.fn(),
+    resolvePrincipal: vi.fn().mockResolvedValue(ANONYMOUS_PRINCIPAL),
+    ...overrides,
+  };
+}
+
+function fakeStore(): AuthorizationStore {
+  return {
+    createGrant: vi.fn(),
+    grantPlatformOwner: vi.fn(),
+    hasActiveGrant: vi.fn().mockResolvedValue(false),
+    isPlatformOwner: vi.fn().mockResolvedValue(false),
+    listGrantsForUser: vi.fn().mockResolvedValue([]),
+    revokeGrant: vi.fn(),
+    revokePlatformOwner: vi.fn(),
+  };
+}
+
+function moduleRoute(fields: RegisteredModuleHttpRoute): RegisteredModuleHttpRoute {
+  return Object.freeze({ ...fields });
+}
+
+function buildModuleApp(options: {
+  readonly evaluator?: AuthorizationEvaluator;
+  readonly registry: PermissionRegistry;
+  readonly routes: readonly RegisteredModuleHttpRoute[];
+  readonly runtime?: EkklesiaIdentityRuntime;
+  readonly trustedOrigins?: readonly string[];
+}) {
+  const evaluator = options.evaluator ?? {
+    authorize: vi.fn().mockResolvedValue({ allowed: true }),
+  };
+  const runtime = options.runtime ?? fakeRuntime();
+  const app = createApiApp({
+    authorization: { evaluator, registry: options.registry, store: fakeStore() },
+    moduleRoutes: options.routes,
+    runtime,
+    trustedOrigins: options.trustedOrigins ?? [trustedOrigin],
+  });
+  return { app, evaluator, runtime };
+}
+
+function permissionRegistry(
+  declarations: ReadonlyArray<{
+    readonly id: PermissionId;
+    readonly baseline: "authenticated" | "public" | "restricted";
+  }>,
+): PermissionRegistry {
+  return createPermissionRegistry(
+    declarations.map((declaration) => ({ ...declaration, description: "Test permission." })),
+  );
+}
+
+describe("module HTTP route mounting", () => {
+  it('mounts a "/" route at exactly the module root, never with an added trailing slash', async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => new Response("root", { status: 200 }));
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const rootResponse = await app.request("/api/v1/modules/calendar");
+    expect(rootResponse.status).toBe(200);
+    expect(await rootResponse.text()).toBe("root");
+    expect(handler).toHaveBeenCalledTimes(1);
+
+    const trailingSlashResponse = await app.request("/api/v1/modules/calendar/");
+    expect(trailingSlashResponse.status).toBe(404);
+  });
+
+  it("mounts static and nested paths directly under the module prefix", async () => {
+    const staticHandler = vi.fn<ModuleRouteHandler>(async () => Response.json({ kind: "static" }));
+    const nestedHandler = vi.fn<ModuleRouteHandler>(async () => Response.json({ kind: "nested" }));
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler: staticHandler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+        moduleRoute({
+          handler: nestedHandler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events/upcoming/soon",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    expect(await (await app.request("/api/v1/modules/calendar/events")).json()).toEqual({
+      kind: "static",
+    });
+    expect(
+      await (await app.request("/api/v1/modules/calendar/events/upcoming/soon")).json(),
+    ).toEqual({ kind: "nested" });
+  });
+
+  it("resolves a same-depth static path and its parameterized sibling by published route order, without silently reordering them", async () => {
+    // Hono's router matches overlapping patterns in registration order, not by specificity —
+    // mounting must therefore preserve `StartedModuleRuntime.routes`' exact publication order
+    // rather than sorting it, or a module author's more-specific-first declaration would silently
+    // stop taking precedence. The static route is declared first here, matching how a module
+    // author would order these two routes to get the static path resolved on its own.
+    const staticHandler = vi.fn<ModuleRouteHandler>(async () => Response.json({ kind: "static" }));
+    const paramHandler = vi.fn<ModuleRouteHandler>(async (_request, context) =>
+      Response.json({ id: context.params.eventId, kind: "param" }),
+    );
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler: staticHandler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events/upcoming",
+          permission: readPermission,
+        }),
+        moduleRoute({
+          handler: paramHandler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events/:eventId",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    expect(await (await app.request("/api/v1/modules/calendar/events/upcoming")).json()).toEqual({
+      kind: "static",
+    });
+    expect(staticHandler).toHaveBeenCalledTimes(1);
+    expect(paramHandler).not.toHaveBeenCalled();
+
+    expect(await (await app.request("/api/v1/modules/calendar/events/other-id")).json()).toEqual({
+      id: "other-id",
+      kind: "param",
+    });
+    expect(paramHandler).toHaveBeenCalledTimes(1);
+  });
+
+  it("mounts every supported method", async () => {
+    const methods = ["GET", "POST", "PUT", "PATCH", "DELETE"] as const;
+    const permissions = new Map(
+      methods.map((method) => [method, parsePermissionId(`multi.${method.toLowerCase()}.action`)]),
+    );
+    const { app } = buildModuleApp({
+      registry: permissionRegistry(
+        methods.map((method) => ({
+          baseline: "public" as const,
+          id: permissions.get(method) as PermissionId,
+        })),
+      ),
+      routes: methods.map((method) =>
+        moduleRoute({
+          handler: async () => Response.json({ method }),
+          method,
+          moduleId: "multi",
+          path: "/action",
+          permission: permissions.get(method) as PermissionId,
+        }),
+      ),
+    });
+
+    for (const method of methods) {
+      const response = await app.request("/api/v1/modules/multi/action", {
+        headers: method === "GET" ? {} : { origin: trustedOrigin },
+        method,
+      });
+      expect(response.status).toBe(200);
+      expect(await response.json()).toEqual({ method });
+    }
+  });
+
+  it("keeps two modules' identical local method/path routes independent", async () => {
+    const alphaPermission = parsePermissionId("alpha.items.list");
+    const betaPermission = parsePermissionId("beta.items.list");
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([
+        { id: alphaPermission, baseline: "public" },
+        { id: betaPermission, baseline: "public" },
+      ]),
+      routes: [
+        moduleRoute({
+          handler: async () => Response.json({ moduleId: "alpha" }),
+          method: "GET",
+          moduleId: "alpha",
+          path: "/items",
+          permission: alphaPermission,
+        }),
+        moduleRoute({
+          handler: async () => Response.json({ moduleId: "beta" }),
+          method: "GET",
+          moduleId: "beta",
+          path: "/items",
+          permission: betaPermission,
+        }),
+      ],
+    });
+
+    expect(await (await app.request("/api/v1/modules/alpha/items")).json()).toEqual({
+      moduleId: "alpha",
+    });
+    expect(await (await app.request("/api/v1/modules/beta/items")).json()).toEqual({
+      moduleId: "beta",
+    });
+  });
+});
+
+describe("module route handler adaptation", () => {
+  it("adapts the request into a raw Fetch Request and a frozen context with decoded parameters", async () => {
+    let capturedRequest: Request | undefined;
+    let capturedContext: ModuleRouteHandlerContext | undefined;
+    const handler: ModuleRouteHandler = async (request, context) => {
+      capturedRequest = request;
+      capturedContext = context;
+      const body = await request.text();
+      return Response.json({ body, url: request.url });
+    };
+    const runtime = fakeRuntime({
+      resolvePrincipal: vi.fn().mockResolvedValue(createAuthenticatedPrincipal("user_1")),
+    });
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "POST",
+          moduleId: "calendar",
+          path: "/events/:eventId/rsvp",
+          permission: readPermission,
+        }),
+      ],
+      runtime,
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events/evt-1/rsvp?notify=true", {
+      body: "hello",
+      headers: { origin: trustedOrigin, "x-custom": "abc" },
+      method: "POST",
+    });
+    const body = (await response.json()) as { body: string; url: string };
+
+    expect(response.status).toBe(200);
+    expect(body.body).toBe("hello");
+    expect(body.url).toContain("/api/v1/modules/calendar/events/evt-1/rsvp?notify=true");
+    expect(capturedRequest).toBeInstanceOf(Request);
+    expect(capturedRequest?.headers.get("x-custom")).toBe("abc");
+    expect(capturedContext).toEqual({
+      moduleId: "calendar",
+      params: { eventId: "evt-1" },
+      principal: { kind: "authenticated", userId: "user_1" },
+    });
+    expect(Object.isFrozen(capturedContext)).toBe(true);
+    expect(Object.isFrozen(capturedContext?.params)).toBe(true);
+  });
+
+  it("gives static and root routes a frozen, empty params object", async () => {
+    let rootContext: ModuleRouteHandlerContext | undefined;
+    let staticContext: ModuleRouteHandlerContext | undefined;
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler: async (_request, context) => {
+            rootContext = context;
+            return Response.json({ ok: true });
+          },
+          method: "GET",
+          moduleId: "calendar",
+          path: "/",
+          permission: readPermission,
+        }),
+        moduleRoute({
+          handler: async (_request, context) => {
+            staticContext = context;
+            return Response.json({ ok: true });
+          },
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    await app.request("/api/v1/modules/calendar");
+    await app.request("/api/v1/modules/calendar/events");
+
+    expect(rootContext?.params).toEqual({});
+    expect(Object.isFrozen(rootContext?.params)).toBe(true);
+    expect(staticContext?.params).toEqual({});
+    expect(Object.isFrozen(staticContext?.params)).toBe(true);
+  });
+});
+
+describe("module route authorization", () => {
+  it("uses the registry's exact baseline for public, authenticated, and restricted module permissions", async () => {
+    const publicPermission = parsePermissionId("calendar.events.list");
+    const authenticatedPermission = parsePermissionId("calendar.events.subscribe");
+    const restrictedPermission = parsePermissionId("calendar.events.read");
+    const evaluator: AuthorizationEvaluator = {
+      authorize: vi.fn().mockResolvedValue({ allowed: true }),
+    };
+    const { app } = buildModuleApp({
+      evaluator,
+      registry: permissionRegistry([
+        { id: publicPermission, baseline: "public" },
+        { id: authenticatedPermission, baseline: "authenticated" },
+        { id: restrictedPermission, baseline: "restricted" },
+      ]),
+      routes: [
+        moduleRoute({
+          handler: async () => Response.json({ ok: true }),
+          method: "GET",
+          moduleId: "calendar",
+          path: "/public",
+          permission: publicPermission,
+        }),
+        moduleRoute({
+          handler: async () => Response.json({ ok: true }),
+          method: "GET",
+          moduleId: "calendar",
+          path: "/authenticated",
+          permission: authenticatedPermission,
+        }),
+        moduleRoute({
+          handler: async () => Response.json({ ok: true }),
+          method: "GET",
+          moduleId: "calendar",
+          path: "/restricted",
+          permission: restrictedPermission,
+        }),
+      ],
+    });
+
+    await app.request("/api/v1/modules/calendar/public");
+    await app.request("/api/v1/modules/calendar/authenticated");
+    await app.request("/api/v1/modules/calendar/restricted");
+
+    expect(evaluator.authorize).toHaveBeenNthCalledWith(
+      1,
+      expect.objectContaining({ baseline: "public", permission: publicPermission }),
+    );
+    expect(evaluator.authorize).toHaveBeenNthCalledWith(
+      2,
+      expect.objectContaining({ baseline: "authenticated", permission: authenticatedPermission }),
+    );
+    expect(evaluator.authorize).toHaveBeenNthCalledWith(
+      3,
+      expect.objectContaining({ baseline: "restricted", permission: restrictedPermission }),
+    );
+  });
+
+  it("does not invoke the handler when authorization denies", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const evaluator: AuthorizationEvaluator = {
+      authorize: vi.fn().mockResolvedValue({ allowed: false }),
+    };
+    const { app } = buildModuleApp({
+      evaluator,
+      registry: permissionRegistry([{ id: readPermission, baseline: "restricted" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.status).toBe(403);
+    expect(await response.json()).toEqual({ code: "AUTHORIZATION_DENIED" });
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  it("does not invoke the handler when principal resolution fails", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const runtime = fakeRuntime({
+      resolvePrincipal: vi.fn().mockRejectedValue(new Error("connection terminated")),
+    });
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "restricted" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+      runtime,
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.status).toBe(503);
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  it("does not invoke the handler when the evaluator itself fails", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const evaluator: AuthorizationEvaluator = {
+      authorize: vi.fn().mockRejectedValue(new Error("connection terminated")),
+    };
+    const { app } = buildModuleApp({
+      evaluator,
+      registry: permissionRegistry([{ id: readPermission, baseline: "restricted" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.status).toBe(503);
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  it("fails app construction safely when a route names a permission the registry does not register", () => {
+    expect(() =>
+      buildModuleApp({
+        registry: permissionRegistry([]),
+        routes: [
+          moduleRoute({
+            handler: vi.fn(),
+            method: "GET",
+            moduleId: "calendar",
+            path: "/events",
+            permission: readPermission,
+          }),
+        ],
+      }),
+    ).toThrow(ModuleRouteConfigurationError);
+  });
+
+  it("never leaks the offending permission, route path, or module id in the configuration error", () => {
+    let captured: unknown;
+    try {
+      buildModuleApp({
+        registry: permissionRegistry([]),
+        routes: [
+          moduleRoute({
+            handler: vi.fn(),
+            method: "GET",
+            moduleId: "secret-module",
+            path: "/secret-path",
+            permission: parsePermissionId("secret-module.secret.permission"),
+          }),
+        ],
+      });
+    } catch (error) {
+      captured = error;
+    }
+
+    expect(captured).toBeInstanceOf(ModuleRouteConfigurationError);
+    const text = `${(captured as Error).message}\n${(captured as Error).stack}`;
+    expect(text).not.toContain("secret-module");
+    expect(text).not.toContain("secret-path");
+    expect(text).not.toContain("secret.permission");
+  });
+});
+
+describe("module route trusted-origin enforcement", () => {
+  it("rejects a state-changing module route with no or untrusted Origin before authorization runs", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const evaluator: AuthorizationEvaluator = {
+      authorize: vi.fn().mockResolvedValue({ allowed: true }),
+    };
+    const methods = ["POST", "PUT", "PATCH", "DELETE"] as const;
+    const { app } = buildModuleApp({
+      evaluator,
+      registry: permissionRegistry([{ id: writePermission, baseline: "public" }]),
+      routes: methods.map((method) =>
+        moduleRoute({
+          handler,
+          method,
+          moduleId: "calendar",
+          path: "/events",
+          permission: writePermission,
+        }),
+      ),
+    });
+
+    for (const method of methods) {
+      const noOriginResponse = await app.request("/api/v1/modules/calendar/events", { method });
+      expect(noOriginResponse.status).toBe(403);
+      expect(await noOriginResponse.json()).toEqual({ code: "UNTRUSTED_ORIGIN" });
+
+      const untrustedResponse = await app.request("/api/v1/modules/calendar/events", {
+        headers: { origin: untrustedOrigin },
+        method,
+      });
+      expect(untrustedResponse.status).toBe(403);
+    }
+    expect(handler).not.toHaveBeenCalled();
+    expect(evaluator.authorize).not.toHaveBeenCalled();
+  });
+
+  it("allows a trusted-origin state-changing request through to the handler", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: writePermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "POST",
+          moduleId: "calendar",
+          path: "/events",
+          permission: writePermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events", {
+      headers: { origin: trustedOrigin },
+      method: "POST",
+    });
+    expect(response.status).toBe(200);
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it("does not require an Origin header for a GET module route", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.status).toBe(200);
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+});
+
+describe("module route CORS", () => {
+  it("advertises GET, POST, PUT, PATCH, and DELETE on preflight", async () => {
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: writePermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler: vi.fn(),
+          method: "PUT",
+          moduleId: "calendar",
+          path: "/events",
+          permission: writePermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events", {
+      headers: { "access-control-request-method": "PUT", origin: trustedOrigin },
+      method: "OPTIONS",
+    });
+
+    expect(response.status).toBe(204);
+    const allowedMethods = response.headers.get("access-control-allow-methods") ?? "";
+    for (const method of ["GET", "POST", "PUT", "PATCH", "DELETE"]) {
+      expect(allowedMethods).toContain(method);
+    }
+  });
+
+  it("never invokes authorization or the handler for an OPTIONS preflight", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const evaluator: AuthorizationEvaluator = {
+      authorize: vi.fn().mockResolvedValue({ allowed: true }),
+    };
+    const { app } = buildModuleApp({
+      evaluator,
+      registry: permissionRegistry([{ id: writePermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "POST",
+          moduleId: "calendar",
+          path: "/events",
+          permission: writePermission,
+        }),
+      ],
+    });
+
+    await app.request("/api/v1/modules/calendar/events", {
+      headers: { "access-control-request-method": "POST", origin: trustedOrigin },
+      method: "OPTIONS",
+    });
+
+    expect(handler).not.toHaveBeenCalled();
+    expect(evaluator.authorize).not.toHaveBeenCalled();
+  });
+
+  it("never reflects an untrusted origin for a module route", async () => {
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler: async () => Response.json({ ok: true }),
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events", {
+      headers: { origin: untrustedOrigin },
+    });
+    expect(response.headers.get("access-control-allow-origin")).toBeNull();
+  });
+});
+
+describe("module route handler failure sanitization", () => {
+  it("returns a fixed sanitized 500 when the handler throws, never leaking the caught message", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => {
+      throw new Error("password=hunter2 host=db.internal.example");
+    });
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    const text = await response.text();
+
+    expect(response.status).toBe(500);
+    expect(JSON.parse(text)).toEqual({ code: "MODULE_HANDLER_FAILED" });
+    expect(text).not.toContain("hunter2");
+    expect(text).not.toContain("db.internal.example");
+    expect(response.headers.get("cache-control")).toBe("no-store");
+  });
+
+  it("returns the same fixed sanitized 500 when the handler rejects", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(() => Promise.reject(new Error("rejected")));
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.status).toBe(500);
+    expect(await response.json()).toEqual({ code: "MODULE_HANDLER_FAILED" });
+  });
+
+  it("returns the same fixed sanitized 500 when the handler returns a non-Response value", async () => {
+    const handler = vi.fn(async () => ({ ok: true }) as unknown as Response);
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.status).toBe(500);
+    expect(await response.json()).toEqual({ code: "MODULE_HANDLER_FAILED" });
+  });
+
+  it("passes through a valid module-owned 4xx/5xx Response unchanged", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () =>
+      Response.json({ code: "MODULE_NOT_FOUND" }, { status: 404 }),
+    );
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.status).toBe(404);
+    expect(await response.json()).toEqual({ code: "MODULE_NOT_FOUND" });
+  });
+});
+
+describe("module route response header policy", () => {
+  it("strips module-supplied CORS-control headers so the platform policy remains authoritative", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(
+      async () =>
+        new Response("body", {
+          headers: {
+            "access-control-allow-credentials": "true",
+            "access-control-allow-methods": "GET, POST, PUT, PATCH, DELETE",
+            "access-control-allow-origin": "*",
+            "access-control-expose-headers": "X-Secret",
+          },
+          status: 200,
+        }),
+    );
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events", {
+      headers: { origin: untrustedOrigin },
+    });
+    expect(response.headers.get("access-control-allow-origin")).not.toBe("*");
+    expect(response.headers.get("access-control-expose-headers")).toBeNull();
+  });
+
+  it("forces Cache-Control: no-store and Vary: Origin, Cookie on a successful module response", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(
+      async () => new Response("body", { headers: { "content-type": "text/plain" }, status: 200 }),
+    );
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    expect(response.headers.get("cache-control")).toBe("no-store");
+    const vary = response.headers.get("vary") ?? "";
+    expect(vary).toContain("Origin");
+    expect(vary).toContain("Cookie");
+  });
+
+  it("preserves an additional legitimate Vary value from the handler alongside the forced ones", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(
+      async () => new Response("body", { headers: { Vary: "Accept-Language" }, status: 200 }),
+    );
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events");
+    const vary = response.headers.get("vary") ?? "";
+    expect(vary).toContain("Accept-Language");
+    expect(vary).toContain("Origin");
+    expect(vary).toContain("Cookie");
+  });
+});
+
+describe("module route HEAD semantics", () => {
+  it("traverses the GET route's permission middleware and returns no body when authorized", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(
+      async () => new Response("body-text", { status: 200 }),
+    );
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events", { method: "HEAD" });
+    expect(response.status).toBe(200);
+    expect(await response.text()).toBe("");
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it("denies a HEAD request exactly like the GET route would, without invoking the handler", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(
+      async () => new Response("body-text", { status: 200 }),
+    );
+    const evaluator: AuthorizationEvaluator = {
+      authorize: vi.fn().mockResolvedValue({ allowed: false }),
+    };
+    const { app } = buildModuleApp({
+      evaluator,
+      registry: permissionRegistry([{ id: readPermission, baseline: "restricted" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/events", { method: "HEAD" });
+    expect(response.status).toBe(403);
+    expect(await response.text()).toBe("");
+    expect(handler).not.toHaveBeenCalled();
+  });
+});
+
+describe("module routes and the rest of the API", () => {
+  it("does not invoke a handler for an unmatched module path", async () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    const { app } = buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+
+    const response = await app.request("/api/v1/modules/calendar/does-not-exist");
+    expect(response.status).toBe(404);
+    expect(await response.json()).toEqual({ code: "NOT_FOUND" });
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  it("never invokes a handler merely by constructing the app", () => {
+    const handler = vi.fn<ModuleRouteHandler>(async () => Response.json({ ok: true }));
+    buildModuleApp({
+      registry: permissionRegistry([{ id: readPermission, baseline: "public" }]),
+      routes: [
+        moduleRoute({
+          handler,
+          method: "GET",
+          moduleId: "calendar",
+          path: "/events",
+          permission: readPermission,
+        }),
+      ],
+    });
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  it("preserves existing API behavior with zero module routes", async () => {
+    const { app } = buildModuleApp({ registry: permissionRegistry([]), routes: [] });
+    const response = await app.request("/api/v1/principal");
+    expect(response.status).toBe(200);
+  });
+});
diff --git a/docs/development/api.md b/docs/development/api.md
index 36b4237..9010016 100644
--- a/docs/development/api.md
+++ b/docs/development/api.md
@@ -57,6 +57,7 @@ No real values are shown here — configure per environment and never commit the
 | `POST\|GET /api/auth/*` | Better Auth (mounted directly) | Better Auth's own request/response shapes pass through unmodified — see [Better Auth's email/password docs](https://www.better-auth.com/docs/authentication/email-password) for the exact endpoints (`/sign-up/email`, `/sign-in/email`, `/sign-out`, `/get-session`, ...). |
 | `GET /api/v1/principal` | Ekklesia | Returns the minimal `EkklesiaPrincipal` contract as JSON. `Cache-Control: no-store`. |
 | `GET\|POST /api/v1/grants*` | Ekklesia | Explicit authorization grant management, gated by `core.authorization.grants.manage`. See [Authorization](authorization.md#explicit-grant-http-api). |
+| `/api/v1/modules/<module-id>/*` | Installed modules | Every route an installed module registered during its `register` hook, gated by that route's own declared permission. See [Module HTTP routes](#module-http-routes). |
 
 Better Auth's handler is unreachable outside `/api/auth/*`; every other unmatched path returns a
 deterministic `404 {"code":"NOT_FOUND"}`.
@@ -206,17 +207,74 @@ trusted-proxy IP policy is configured, Better Auth may fall back to a single sha
 rather than a genuine per-client bucket. This is not yet the final, distributed, production-grade
 abuse-control design.
 
-## Module permission discovery at startup
+## Module discovery, permission composition, and module runtime startup
 
-Before any database pool, Better Auth instance, or HTTP server exists, `startApi()` discovers
-every installed module's manifest and composes the one immutable platform permission registry
-(Core's own declarations plus every module's) that the rest of startup — and every subsequent
-request — enforces against. A discovery or composition failure (an invalid manifest, a module
-claiming the reserved `core.*` permission namespace, a duplicate permission declaration, ...) fails
-startup outright, before there is anything to close; startup never falls back to a Core-only
-registry. See [Authorization](authorization.md#api-startup-discovery-composition-and-enforcement)
-for the full flow, and [Module development](module-development/README.md) for the manifest shape
-that produces these declarations.
+`startApi()` composes production in one fixed order:
+
+1. Discover every installed module's manifest exactly once and compose the one immutable platform
+   permission registry (Core's own declarations plus every module's) — `prepareStartupModuleInventory`,
+   `apps/api/src/platform-permissions.ts`.
+2. Construct the one shared PostgreSQL pool.
+3. Construct the Core identity runtime, authorization store, and evaluator.
+4. Start the module runtime from that exact same discovered inventory
+   (`startDiscoveredModuleRuntime`) — modules are never rediscovered for this step.
+5. Create the Hono application, mounting the started module runtime's published routes.
+6. Bind the HTTP server.
+
+Discovery and permission composition happen before any pool, Better Auth instance, module
+entrypoint import, or HTTP server exists, so a discovery or composition failure (an invalid
+manifest, a module claiming the reserved `core.*` permission namespace, a duplicate permission
+declaration, ...) fails startup outright, before there is anything to close; startup never falls
+back to a Core-only registry. Core infrastructure exists before any executable module lifecycle
+code runs, and every module route is published only after the *entire* module runtime has
+registered and started successfully, so no request can ever reach a module before every module has
+started. See [Authorization](authorization.md#api-startup-discovery-composition-and-enforcement)
+for the permission-composition detail, and [Module development](module-development/README.md) for
+the manifest shape that produces these declarations.
+
+Unlike discovery/composition/Doctor/`modules:validate` (which only ever read manifests), a
+successful production startup does import each module's compiled server entrypoint and run its
+`register`/`start` hooks — this is the one place in the platform that deliberately executes module
+code, and only after every other startup step already listed has succeeded.
+
+## Module HTTP routes
+
+An installed module's routes (declared via `http.route(...)` in its `register` hook — see
+[Module development](module-development/README.md#http-routes) for the module-authoring contract)
+are mounted under `/api/v1/modules/<module-id>`, in the module runtime's published order, by
+`apps/api/src/module-http-routes.ts`. Mounting never invokes a handler.
+
+- **Enforcement.** Every route runs through the identical `requirePermission` middleware Core's own
+  routes use, with the route's own declared permission id as the only permission ever consulted —
+  its trusted baseline always comes from the composed platform registry, never from the route or
+  the request. A `public`, `authenticated`, and `restricted` module permission are enforced through
+  the exact same path; a public-baseline route still resolves and receives an authorized principal.
+- **Trusted origin.** `POST`, `PUT`, `PATCH`, and `DELETE` module routes additionally require an
+  exact trusted `Origin` (see [Origin, CORS, and cookies](#origin-cors-and-cookies)) before
+  authorization ever runs, exactly like the existing grants-mutation routes. `GET` does not require
+  one. `OPTIONS` remains entirely platform-owned: a module cannot register it, and a CORS preflight
+  never reaches authorization or a handler. `GET` inherits Hono's own implicit `HEAD` handling
+  (same permission check, response body stripped); a module cannot separately author `HEAD`.
+- **Handler input.** A handler receives the raw Fetch `Request` (so `Request.url`, headers, and
+  body all behave normally, and the full query string remains available) plus a frozen context of
+  exactly `moduleId`, the authorized `EkklesiaPrincipal`, and frozen, Hono-decoded path parameters
+  (an empty frozen object for a route with none) — never a Hono `Context`, a database connection,
+  the authorization store, storage, jobs, configuration, or secrets.
+- **Handler failure.** A handler that throws, rejects, or returns anything other than a `Response`
+  becomes a fixed `500 {"code":"MODULE_HANDLER_FAILED"}` with `Cache-Control: no-store` — never the
+  caught value, a stack, the route's path or permission id, or the module id. A `Response` a
+  handler deliberately returns — including a 4xx/5xx one — passes through unchanged.
+- **CORS and caching.** The platform remains the sole owner of CORS for module routes exactly like
+  every other `/api/v1/*` route (see [Origin, CORS, and cookies](#origin-cors-and-cookies), now
+  additionally advertising `PUT`/`PATCH`/`DELETE`); any CORS-control header a handler sets on its
+  own response is stripped before the response leaves the process. Every module response is forced
+  to `Cache-Control: no-store` and a `Vary` that always includes `Origin` and `Cookie` (a handler's
+  own legitimate `Vary` values are preserved alongside those) — deliberately conservative until a
+  dedicated cache-policy contract exists, since even a public-baseline handler receives an
+  authorized principal and may personalize its response.
+- **Static snapshot.** Routes are part of the same static startup snapshot as the permission
+  registry: installing, removing, or editing a module's routes takes effect only on the next API
+  restart. Removing a module makes its former routes return the ordinary `404 {"code":"NOT_FOUND"}`.
 
 ## Database connection limits
 
@@ -239,17 +297,25 @@ not two.
 `startApi()` (the composition function `apps/api/src/server.ts` exports, used by both the
 executable entry point and tests) returns `{app, server, shutdown}`. `shutdown()` memoizes one
 shared promise the first time it is called: every caller, concurrent or sequential, awaits the
-exact same listener-drain-then-pool-close operation, and that operation runs exactly once no matter
-how many times `shutdown()` is called. It stops the HTTP listener from accepting new connections and
-lets in-flight requests finish, then closes the one shared PostgreSQL pool (identity and
-authorization both read from it — see
-[Authorization](authorization.md#shared-database-composition)). The executable entry point's
-`SIGINT`/`SIGTERM` wiring is extracted into `installShutdownSignalHandlers(running, exit)` — the
-same function production composition uses, but independently testable with a fake `running`/`exit`
-so a test can trigger "a signal arrived" without sending a real process signal or invoking the real
-`process.exit`. A startup failure after the database pool was already created (identity
-construction failure, or the server failing to bind its listen address) always closes that pool
-before the failure propagates.
+exact same operation, and that operation runs exactly once no matter how many times `shutdown()`
+is called. In order: it stops the HTTP listener from accepting new connections and lets in-flight
+requests finish; then stops the module runtime (so no module resource stops while a route handler
+might still be in flight); then closes the one shared PostgreSQL pool (identity and authorization
+both read from it — see [Authorization](authorization.md#shared-database-composition)). Unlike a
+startup-failure cleanup path (below), a module-stop failure here is not swallowed — it is a
+genuine result a caller should observe — but pool cleanup always still runs first, so a stop
+failure never leaves the pool open. The executable entry point's `SIGINT`/`SIGTERM` wiring is
+extracted into `installShutdownSignalHandlers(running, exit)` — the same function production
+composition uses, but independently testable with a fake `running`/`exit` so a test can trigger "a
+signal arrived" without sending a real process signal or invoking the real `process.exit`.
+
+A startup failure after the database pool was already created always closes that pool before the
+failure propagates: identity/authorization construction failing (no module runtime was started
+yet); the server failing to bind its listen address; or an app-construction failure, both of which
+also stop the module runtime first, since it may have already started successfully. A module
+load/register/start failure uses Core's own existing rollback (already-started modules stop, in
+reverse order, before the failure propagates) and then closes the pool — there is no separate
+runtime handle to stop in that case, since `startDiscoveredModuleRuntime` never returned one.
 
 ## A real signup → sign-in → principal → sign-out transcript
 
diff --git a/docs/development/authorization.md b/docs/development/authorization.md
index 7bc9243..7f1954c 100644
--- a/docs/development/authorization.md
+++ b/docs/development/authorization.md
@@ -16,14 +16,15 @@ for the durable architectural decisions this page describes in more implementati
 
 An operator can bootstrap exactly one platform owner for a deployment; a platform owner (or anyone
 they delegate to) can create, list, and revoke *explicit* authorization grants over HTTP for any
-registered permission, Core-owned or module-owned; and every enforced route fails closed on
-infrastructure trouble instead of silently allowing or denying. It is **not** possible to manage
-roles, groups, teams, or tenants; there is no owner-management HTTP endpoint (revoking or
-re-granting platform-owner status is not exposed at all); there are no service accounts or API
-tokens, so only cookie-authenticated browser callers can reach the mutation routes; a module cannot
-yet mount its own HTTP routes; and relationship-derived grants (for example, automatic access from
-a roster assignment) cannot yet be created by anything in this repository — the generic grants API
-structurally cannot create or revoke them either.
+registered permission, Core-owned or module-owned; a module can register its own HTTP routes and
+have them mounted, enforced, and reachable in production (see
+[API](api.md#module-http-routes)); and every enforced route fails closed on infrastructure trouble
+instead of silently allowing or denying. It is **not** possible to manage roles, groups, teams, or
+tenants; there is no owner-management HTTP endpoint (revoking or re-granting platform-owner status
+is not exposed at all); there are no service accounts or API tokens, so only cookie-authenticated
+browser callers can reach mutation routes, Core-owned or module-owned; and relationship-derived
+grants (for example, automatic access from a roster assignment) cannot yet be created by anything
+in this repository — the generic grants API structurally cannot create or revoke them either.
 
 ## Core authorization schema and store
 
@@ -105,27 +106,37 @@ integration layer depends on authorization).
 
 ## API startup: discovery, composition, and enforcement
 
-`apps/api` builds its production permission registry from the complete installed-module inventory
-every time it starts, in a fixed order, before anything else:
+`apps/api` builds its production permission registry, and starts the module runtime, from the
+exact same installed-module inventory every time it starts, in a fixed order, before anything
+else:
 
 1. Resolve module-discovery configuration (the repository's `modules/` directory, and the
    platform/Module SDK versions from their own `package.json` files).
-2. Discover installed modules (`discoverModules`).
-3. Compose the platform permission registry (`composePlatformPermissionRegistry`).
+2. Discover installed modules exactly once (`discoverModules`).
+3. Compose the platform permission registry from that exact discovered list
+   (`composePlatformPermissionRegistry`).
 4. Construct the shared PostgreSQL pool.
-5. Construct Identity and Authorization.
-6. Create the Hono application, injecting the composed registry.
-7. Bind the HTTP server.
+5. Construct Identity, the authorization store, and the evaluator.
+6. Start the module runtime from that same discovered list (`startDiscoveredModuleRuntime`) —
+   modules are never rediscovered for this step.
+7. Create the Hono application, injecting the composed registry and mounting the started module
+   runtime's published routes (see [API](api.md#module-http-routes)).
+8. Bind the HTTP server.
 
-`apps/api/src/platform-permissions.ts`'s `composeStartupPermissionRegistry` performs steps 1–3.
-Discovery and composition happen strictly before any pool, Better Auth instance, or HTTP server
-exists, so a failure there — an invalid manifest, a broken dependency graph, a module claiming the
-reserved `core.*` namespace, or a duplicate permission declaration — leaves nothing to close: it
-propagates directly out of `startApi()`, and startup never falls back to `CORE_PERMISSION_REGISTRY`
-or any Core-only registry. The repository root is resolved from this compiled/source file's own
-location (two directories up from `apps/api/dist/*.js` or `apps/api/src/*.ts`, which sit at
-identical depth), never `process.cwd()` — a package-scoped test run has `apps/api` as its working
-directory, which would otherwise point discovery at the wrong `modules/` directory.
+`apps/api/src/platform-permissions.ts`'s `prepareStartupModuleInventory` performs steps 1–3,
+returning both the discovered module list and the composed registry so step 6 can start the module
+runtime from that identical list rather than rediscovering modules a second time.
+(`composeStartupPermissionRegistry` remains available as a registry-only convenience wrapper
+around it, for callers — Doctor, `modules:validate`, existing tests — that only need the
+registry.) Discovery and composition happen strictly before any pool, Better Auth instance, module
+entrypoint import, or HTTP server exists, so a failure there — an invalid manifest, a broken
+dependency graph, a module claiming the reserved `core.*` namespace, or a duplicate permission
+declaration — leaves nothing to close: it propagates directly out of `startApi()`, and startup
+never falls back to `CORE_PERMISSION_REGISTRY` or any Core-only registry. The repository root is
+resolved from this compiled/source file's own location (two directories up from
+`apps/api/dist/*.js` or `apps/api/src/*.ts`, which sit at identical depth), never `process.cwd()`
+— a package-scoped test run has `apps/api` as its working directory, which would otherwise point
+discovery at the wrong `modules/` directory.
 
 The resulting registry is a **static, immutable snapshot** taken once at startup. There is no hot
 installation, removal, or dynamic mutation of installed modules or their permissions while the
@@ -148,10 +159,11 @@ consults the registry for a grant that already exists — revocation is keyed to
 and source kind, not to whether its permission is currently registered — so a manager can still
 revoke a historical grant for a now-unregistered permission.
 
-Module HTTP route registration (a module owning its own mounted endpoints) and relationship-derived
-grant creation both remain deferred, unrelated slices — this work only makes a module's *declared*
-permission usable through Core's existing, generic explicit-grant HTTP API and enforcement
-middleware.
+A module's own mounted HTTP routes (`/api/v1/modules/<module-id>/*`) are enforced through this
+identical registry and `requirePermission` middleware — see [API](api.md#module-http-routes) for
+the route-mounting contract. Relationship-derived grant creation remains a deferred, unrelated
+slice — this work only makes a module's *declared* permission usable through Core's existing,
+generic explicit-grant HTTP API, enforcement middleware, and now its own mounted routes.
 
 ## Doctor and modules:validate
 
@@ -446,12 +458,34 @@ there are or whether the failure happened during startup.
   `403` and `store.createGrant` never called, exact server-derived-argument assertions,
   sourceKind-filtered revoke returning 404 for a non-explicit grant, origin enforcement, and
   store-error mapping.
+- `apps/api/tests/module-http-routes.test.ts` — the production route-mounting contract: exact
+  prefix/path joining (including the non-trailing-slash root case), every supported method,
+  independent same-path routes across two modules, deterministic static-versus-parameterized
+  resolution by published order, request/handler adaptation (raw `Request`, frozen context, decoded
+  and frozen path parameters, empty frozen params for static/root routes), the registry's exact
+  baseline for `public`/`authenticated`/`restricted` module permissions, denial/infrastructure-
+  failure paths never invoking the handler, `ModuleRouteConfigurationError` for an inconsistent
+  route/registry snapshot, trusted-origin enforcement for state-changing methods, CORS (advertised
+  methods, no reflection for an untrusted origin, no authorization or handler invocation on
+  preflight), fixed sanitized `500` for a throwing/rejecting/non-`Response`-returning handler with
+  no raw leakage, a valid module-owned 4xx/5xx response passing through unchanged, forced
+  `Cache-Control`/`Vary` with a handler's own `Vary` preserved, stripped module-supplied CORS
+  headers, `HEAD` traversing the same permission middleware as `GET` with no body, and unmatched
+  paths/zero-route/no-handler-during-construction behavior.
 - `apps/api/tests/lifecycle.test.ts` — shared-pool-closes-exactly-once coverage described above,
   plus module-permission composition at startup: discovery/composition run before any pool,
   Better Auth instance, or HTTP server is constructed; a discovery failure, a reserved-namespace
   failure, and a generic duplicate-declaration failure each create zero pools/Better Auth
   instances/servers and remain distinguishable from one another; zero installed modules still
-  succeeds; and import safety for `platform-permissions.ts`.
+  succeeds; and import safety for `platform-permissions.ts`. A dedicated block covers module
+  *runtime* startup and shutdown against real, working (non-throwing) fixture modules: permission
+  composition and module runtime startup share the exact same discovered inventory, route mounting
+  order matches discovery order, a load/register/start failure each close the pool exactly once and
+  bind no server (preserving Core's own rollback for a start failure), an app-construction failure
+  and a bind failure both stop the module runtime before closing the pool, normal shutdown stops the
+  server/module-runtime/pool in that exact order, a module stop failure still runs pool cleanup
+  before the shutdown rejection surfaces, and a direct `discoveredModulesOverride` drives both
+  composition and runtime startup identically.
 - `core/tests/authorization-evaluator.test.ts` — includes a malformed permission id denying under
   every baseline (`public`, `authenticated`, `restricted`), never just `restricted`, and never
   consulting the grant or platform-owner ports for `public`/`authenticated`.
@@ -466,16 +500,23 @@ there are or whether the failure happened during startup.
   invisible to LIST and unreachable by REVOKE, and an infrastructure-failure scenario (database
   dropped out from under a live session) asserting a `503` rather than a false `403` or `200`.
 - `apps/api/tests/api-http.integration.ts`, "installed module permission end-to-end" (live
-  PostgreSQL) — a real temporary module fixture (structurally valid manifest, a server entrypoint
-  that throws if ever imported) proves the complete chain against a real API process and real
-  Doctor run: Doctor recognizes the installed module and passes permission composition without
-  executing its entrypoint; API startup discovers the fixture and makes its declared permission
-  enforceable; a bootstrapped platform owner creates a real explicit grant for the module's
-  permission with an atomic audit row recorded under its exact declared id; a well-formed
-  permission absent from the composed registry is rejected with no grant or audit write; and,
-  after a clean shutdown and restart with the module absent, the same permission can no longer be
-  newly granted while the earlier, still-unrevoked grant remains listed — with ordinary identity
-  HTTP behavior (sign-up, sign-in, principal resolution) unaffected throughout.
+  PostgreSQL) — a real temporary module fixture (structurally valid manifest; a real, working
+  server entrypoint recording register/start/stop markers instead of throwing, and declaring a
+  restricted `GET /events/:eventId` route plus a restricted, state-changing `POST /events` route
+  against its own manifest permission) proves the complete chain against a real API process and
+  real Doctor run: Doctor recognizes the installed module and passes permission composition
+  without executing its entrypoint (an empty marker set); a successful `startApi()` discovers the
+  same fixture, imports/registers/starts its runtime exactly once, and makes its declared
+  permission enforceable; a bootstrapped platform owner creates a real explicit grant for the
+  module's permission with an atomic audit row recorded under its exact declared id; the module's
+  own mounted route denies an anonymous caller and then serves the newly granted owner with the
+  decoded path parameter and authenticated principal; the module's state-changing route requires a
+  trusted `Origin` exactly like the platform's own mutation routes; a well-formed permission absent
+  from the composed registry is rejected with no grant or audit write; and, after a clean shutdown
+  (module stop invoked exactly once) and restart with the module absent, its former route returns
+  the ordinary `404`, the same permission can no longer be newly granted, and the earlier,
+  still-unrevoked grant remains listed — with ordinary identity HTTP behavior (sign-up, sign-in,
+  principal resolution) unaffected throughout.
 
 Run the focused suites:
 
@@ -487,10 +528,11 @@ pnpm test:migrations:integration   # requires Docker
 
 ## Next phase
 
-Deliberately deferred, unrelated slices — see
+Module HTTP route registration and production mounting (see
 [ADR 0014](../architecture/decisions/0014-module-permission-declarations-and-platform-registry.md#deferred)
-for the complete list: module HTTP route-registration contracts (a module mounting its own
-endpoints), a module runtime-context authorization service, relationship-derived grant creation
+for the deferral this closes) is now implemented — see [API](api.md#module-http-routes) and
+[Module development](module-development/README.md#http-routes). Deliberately deferred, unrelated
+slices remain: a module runtime-context authorization service, relationship-derived grant creation
 itself (a roster or similar module operation, not the generic grants API), reinstall/reactivation
 policy for a permission whose owning module was previously removed, roles/groups/teams/tenants, an
 owner-management HTTP endpoint, and service accounts/API tokens for non-browser automation.
diff --git a/docs/module-development/README.md b/docs/module-development/README.md
index 429158c..d465eeb 100644
--- a/docs/module-development/README.md
+++ b/docs/module-development/README.md
@@ -240,11 +240,20 @@ connection, authorization store, grant/platform-owner state, storage, jobs, conf
 a framework-specific request context, or a raw Better Auth session. The full query string remains
 available through `Request.url`; there is no separate query or body abstraction.
 
-This pass only defines, validates, and collects routes into `StartedModuleRuntime`'s immutable route
-snapshot — Core never invokes a handler here. Mounting routes into the production `apps/api` Hono
-application, enforcing each route's permission through `requirePermission`, applying
-`requireTrustedOrigin`, mapping handler errors to sanitized responses, and wiring this into
-`startApi`'s production lifecycle are later work.
+Core defines, validates, and collects routes into `StartedModuleRuntime`'s immutable route
+snapshot — it never invokes a handler itself. `apps/api` mounts that exact snapshot into production
+at startup, under the `/api/v1/modules/<module-id>` prefix described above: every route is enforced
+through the identical `requirePermission` middleware Core's own routes use, a state-changing method
+(`POST`/`PUT`/`PATCH`/`DELETE`) additionally requires a trusted `Origin` before authorization ever
+runs, and a handler that throws, rejects, or returns something other than a `Response` becomes a
+fixed, sanitized `500 {"code":"MODULE_HANDLER_FAILED"}` — never the caught value, a stack, the
+route's path, its permission id, or the module id. The platform remains the sole owner of CORS and
+caching for every module route: a handler-supplied CORS-control header is stripped, and every
+module response is forced to `Cache-Control: no-store` with `Vary: Origin, Cookie` (in addition to
+any of the handler's own legitimate `Vary` values) until a dedicated cache-policy contract exists —
+deliberately conservative, since even a public-baseline handler still receives an authorized
+principal and may personalize its response. See [API](../development/api.md#module-http-routes) for
+the full production mounting, enforcement, and error-response contract.
 
 ## Drizzle schema definition