2026-08-23 16:26:17 +02:00
32 changed files with 858 additions and 91 deletions
@@ -93,6 +93,16 @@ Revisit only if the stated reason stops holding.
  plugin cannot destroy data — boot logs the orphans instead. Because the host's copy sits in the
  ambient `/node_modules`, a plugin can `import "postgres"` without declaring it — incidental, not a
  packaging promise, and a plugin must still depend on its own driver.
+  - **Plugin settings are declared, not discovered** (README → Plugin settings). `settings.ts` is pure and
+  takes the env as an argument, so the whole matrix unit-tests without a stack. Four rules carry the
+  design: the prefix is `PLUGIN_SETTING_`, never bare `PLUGIN_`, because a plugin id `db` with key
+  `url` would otherwise name the host's own `PLUGIN_DB_URL`; keys are camelCase so the
+  `camelCase → SNAKE_CASE` mapping is total and no two keys collide, with the residual cross-plugin
+  collision caught by `findConflicts`; `required` and `default` are mutually exclusive, which is what
+  lets `SettingsOf` type a declared key as present rather than `T | undefined`, so no plugin author
+  casts; and a secret's value reaches the plugin but never a log, an error or `ctx.declaredSettings`
+  — not even as a mask or a length. An author mistake is refused at discovery, a bad operator value
+  refuses the boot, and a stray `PLUGIN_SETTING_` variable only warns (the orphan-database precedent).
 - **The trust boundary is the `web` process, not the plugin.** Per-plugin databases and roles bound
  *accidents*, not hostile plugins: `PLUGIN_DB_SECRET` is in `web`'s environment during `onBoot`, and
  a plugin already holds `ctx.system`'s Ory admin clients — so cross-plugin DB isolation is
@@ -47,7 +47,7 @@ folder under `plugins/` goes live after a restart. Create `plugins/hello/plugin.
 import { definePlugin } from "@plainpages/plugin-api";

 export default definePlugin({
-  apiVersion: "0.1.0",
+  apiVersion: "0.2.0",
  nav: [{ href: "/hello", id: "hello", label: "Hello", public: true }],
  routes: [
    { method: "GET", path: "/", public: true, handler: () => ({ html: "<h1>Hello from my plugin</h1>" }) },
@@ -89,6 +89,7 @@ From here, render real pages against the app shell and fetch upstream data — s
  - [hooks](#hooks)
  - [where they live & mounting](#where-plugins-live-and-how-to-mount-them)
  - [dependencies](#plugin-dependencies)
+  - [settings](#plugin-settings)
  - [storage](#plugin-storage)
  - [local dev & test](#local-dev--test-story)
 - [The menu system](#the-menu-system)
@@ -348,7 +349,7 @@ import { definePlugin } from "@plainpages/plugin-api";
 import { listThings, createThings } from "./handlers.ts";

 export default definePlugin({
-  apiVersion: "0.1.0",                // semver string of the host contract this plugin was built against (see Versioning)
+  apiVersion: "0.2.0",                // semver string of the host contract this plugin was built against (see Versioning)

  // Nav fragment, merged into the global menu and permission-filtered per user.
  // `icon` is a Lucide icon by its sprite id (src/ui/icons.ts).
@@ -381,6 +382,7 @@ folder-derived `id` to produce the loaded `Plugin`.
 | `permissions` | no | Permissions this plugin gates on. See [Nav & permission gates](#nav--permission-gates). |
 | `routes` | no | See [Routes & handlers](#routes--handlers). |
 | `hooks` | no | See [Hooks](#hooks). |
+| `settings` | no | Configuration this plugin accepts, one `PLUGIN_SETTING_<ID>_<KEY>` variable per key, resolved and validated at boot and handed to `onBoot`. See [Plugin settings](#plugin-settings). |
 | `storage` | no | `true` ⇒ the host provisions a Postgres database and login role for this plugin and hands the credentials to `onBoot`. See [Plugin storage](#plugin-storage). |

 A plugin may be routes-only, nav-only, or hooks-only — every collection field is optional.
@@ -468,7 +470,7 @@ import { definePlugin } from "@plainpages/plugin-api";
 import { landing, board } from "./pages.ts";

 export default definePlugin({
-  apiVersion: "0.1.0",
+  apiVersion: "0.2.0",
  home: landing,     // owns "/" — the public front page
  dashboard: board,  // owns "/dashboard" — the post-login app home
 });
@@ -736,6 +738,56 @@ barrel's types on disk: typecheck it mounted under the host tree, or vendor a ty
 `node_modules`** and point tsconfig `paths` at it — a stub inside is the shadowing copy discovery
 refuses, and it would travel with the folder you mount.

+### Plugin settings
+
+A plugin declares the configuration it accepts, and the host resolves it from the environment at
+boot. Each key becomes one variable — `PLUGIN_SETTING_<ID>_<KEY>`, the id's dashes and the key's
+camel humps both becoming underscores — so `upstream` on the `scheduling` plugin is set by
+`PLUGIN_SETTING_SCHEDULING_UPSTREAM`.
+
+```ts
+export default definePlugin({
+  apiVersion: "0.2.0",
+  settings: [
+    { key: "upstream", type: "url", required: true, description: "Base URL of the backend" },
+    { key: "pageSize", type: "number", default: 25 },
+    { key: "mode", type: "enum", values: ["strict", "lenient"], default: "strict" },
+    { key: "apiKey", type: "string", secret: true, default: "dev-insecure-key" },
+  ],
+  hooks: {
+    onBoot: ({ settings }) => {
+      settings.upstream; // string  — required, so the boot already refused without it
+      settings.pageSize; // number  — defaulted, so always present
+      start(settings);
+    },
+  },
+});
+```
+
+`type` is one of `string`, `number`, `boolean`, `enum` (with `values`) or `url`. A declared type is
+coerced and checked at boot, so a mistyped value names the plugin, the key and the variable instead
+of surfacing later as a broken page.
+
+**`required` and `default` are mutually exclusive** — a default means the setting can never fail, so
+declaring both is refused at discovery. That leaves three cases, and the type `onBoot` receives
+follows them exactly: `required: true` is always present, a `default` is always present, and a
+setting with neither is `T | undefined`, so the plugin has to handle its absence.
+
+**Secrets.** `secret: true` marks a value the host reads but never renders — not in a boot log, not
+in an error, not on the admin screen, which shows only whether it resolved and from where. With
+`REQUIRE_SECURE_SECRETS=true` a secret that is unset, or still equal to its declared default, refuses
+the boot — the same rule the host applies to its own secrets.
+
+**Where it fails, and where it warns.** A malformed declaration is refused at discovery; a missing
+`required` value or a value that will not coerce refuses the boot. A `PLUGIN_SETTING_` variable no
+installed plugin declares is only *reported* — it is usually a typo in the one the operator meant to
+set, and naming it turns two unrelated-looking errors into one. Declaring settings without an
+`onBoot` warns too: they resolve, but nothing receives them.
+
+**Reading what a deployment is configured with.** The admin plugin's **Plugin settings** screen
+(`plugin-settings:read`) lists every installed plugin, its declared keys, the variable that sets
+each, and whether the value came from the environment or the declared default.
+
 ### Plugin storage

 A plugin that needs to keep data sets `storage: true`. The host then provisions a Postgres
@@ -749,7 +801,7 @@ import { definePlugin } from "@plainpages/plugin-api";
 let sql: ReturnType<typeof postgres>;

 export default definePlugin({
-  apiVersion: "0.1.0",
+  apiVersion: "0.2.0",
  storage: true,
  hooks: {
    onBoot: async (boot) => {
@@ -1030,7 +1082,7 @@ The app is **environment-agnostic**: no `NODE_ENV`, every behaviour its own expl
 | `PORT` | `3000` | web listen port |
 | `CACHE_TEMPLATES` | `false` | cache compiled EJS templates (`true` in prod) |
 | `SECURE_COOKIES` | `false` | mark our session/CSRF cookies `Secure` (`true` in prod https; off in dev http) |
-| `REQUIRE_SECURE_SECRETS` | `false` | when `true`, `CSRF_SECRET` — and `PLUGIN_DB_SECRET` once storage is configured — must be supplied and differ from the dev throwaway |
+| `REQUIRE_SECURE_SECRETS` | `false` | when `true`, `CSRF_SECRET` — and `PLUGIN_DB_SECRET` once storage is configured, and every plugin setting declared `secret` — must be supplied and differ from the dev throwaway |
 | `LOG_LEVEL` | `info` | min severity logged: `error`/`warn`/`info`/`verbose`/`debug`/`silly`/`none` |
 | `LOG_FORMAT` | `text` | log line format: `text` (human-readable, dev) or `json` (structured, prod) |
 | `SERVICE_NAME` | `plainpages` | OTLP `service.name` on every log + span — brand it as your own deployment |
@@ -1047,6 +1099,7 @@ The app is **environment-agnostic**: no `NODE_ENV`, every behaviour its own expl
 | `REVOCATION_TTL_SEC` | `900` | how long a revoke entry lives; keep ≥ tokenizer TTL (10m) + clock skew |
 | `CSRF_SECRET` | dev throwaway | signs our double-submit CSRF token; enforced by `REQUIRE_SECURE_SECRETS` |
 | `PLUGIN_DB_URL` | _unset_ (dev: `postgres://postgres:5432`) | credential-free Postgres base URL for [plugin storage](#plugin-storage); unset ⇒ storage off, and a plugin declaring it aborts boot |
+| `PLUGIN_SETTING_<ID>_<KEY>` | per declaration | one variable per key a plugin declares in `settings`; see [Plugin settings](#plugin-settings) |
 | `PLUGIN_DB_ADMIN_URL` | _unset_ (dev: the bundled superuser) | the DSN that provisions each plugin's database and role — read by the one-shot `bootstrap` service **only**, never by `web` |
 | `PLUGIN_DB_SECRET` | dev throwaway | derives each plugin's database password; `REQUIRE_SECURE_SECRETS` enforces it in `web` once `PLUGIN_DB_URL` is set, and in `bootstrap` whenever a plugin declares storage |
 | `PLUGIN_DB_CONNECTION_LIMIT` | `10` | per-role Postgres connection ceiling, so one plugin's pools cannot exhaust the server Ory shares; read by `bootstrap` when provisioning |
@@ -22,7 +22,7 @@ services:
      PLUGIN_DB_URL: *plugin-db-url
      REQUIRE_SECURE_SECRETS: "false"
      SECURE_COOKIES: "false" # dev serves http — Secure cookies wouldn't be sent
-      SCHEDULING_UPSTREAM: "http://shifts-upstream:4000" # backs the reference plugin once you copy it into plugins/
+      PLUGIN_SETTING_SCHEDULING_UPSTREAM: "http://shifts-upstream:4000" # backs the reference plugin once you copy it into plugins/
    volumes:
      - .:/app
      # Mount your own menu/branding override into the empty config/ dir (defaults apply otherwise):
@@ -46,8 +46,8 @@ services:

  # Mock backend ready for the reference plugin (examples/plugins/scheduling): plugins/ ships empty, so
  # the plugin is opt-in — `cp -r examples/plugins/scheduling plugins/scheduling`, restart, and this
-  # backs it (SCHEDULING_UPSTREAM above points here). Stand-in for the customer's real service —
-  # stdlib-only, in-memory, no auth. Prod points SCHEDULING_UPSTREAM at the real backend instead.
+  # backs it (PLUGIN_SETTING_SCHEDULING_UPSTREAM above points here). Stand-in for the customer's real service —
+  # stdlib-only, in-memory, no auth. Prod points PLUGIN_SETTING_SCHEDULING_UPSTREAM at the real backend instead.
  shifts-upstream:
    image: node:24.19.0-alpine3.24
    command: node /srv/server.ts
@@ -195,6 +195,17 @@ test.describe.serial("authenticated admin journey", () => {
    await expect(page.locator("table")).toContainText("Morning — Front desk"); // seeded by the mock upstream
  });

+  test("plugin settings: the screen names the variable that sets each declared key", async () => {
+    await page.goto("/admin/plugin-settings");
+    await expect(page.locator("h1")).toHaveText("Plugin settings");
+    // The reference plugin's one declared setting, and the variable an operator would set for it.
+    const scheduling = page.locator("table").filter({ hasText: "PLUGIN_SETTING_SCHEDULING_UPSTREAM" });
+    await expect(scheduling).toContainText("upstream");
+    await expect(scheduling).toContainText("http://shifts-upstream:4000"); // resolved, and its source shown
+    // Every installed plugin gets a section, so "declares none" is distinguishable from "not installed".
+    await expect(page.locator("h2", { hasText: "admin" })).toHaveCount(1);
+  });
+
  test("logout: signing out ends the session and returns to the login page", async () => {
    await page.goto("/dashboard");
    await page.locator("button.profile").click(); // open the profile dropdown
@@ -8,4 +8,4 @@ across (or bind-mount your own) and restart.
 | [`plugins/scheduling/`](plugins/scheduling/) | `plugins/scheduling/` | The reference plugin: a list page over an upstream REST service, a CSRF-guarded form that forwards a write, and permission-gated nav — built from the core building blocks, holding no state. Imports the host surface as `@plainpages/plugin-api`. See its [README](plugins/scheduling/README.md) and the [plugin contract](../README.md#building-plugins). |
 | [`plugins/admin/`](plugins/admin/) | `plugins/admin/` | The system-admin plugin: the Users / Groups / Permissions / OAuth2-clients screens for running Plainpages itself. A *system* plugin — it administers the Ory identity stack via the privileged [`ctx.system`](../README.md#system-capabilities-the-ctxsystem-surface) surface instead of its own upstream. Copy it in to get a GUI for user & group admin. See its [README](plugins/admin/README.md). |
 | [`config/menu.ts`](config/menu.ts) | `config/menu.ts` | The central menu override + branding template (rename/group/order/hide nav, set app name/logo/theme). Imports its typed builder as `#menu-config`; `config/` ships empty, so defaults apply until you copy this in. See [The menu system](../README.md#the-menu-system). |
-| [`shifts-upstream/`](shifts-upstream/) | — (dev service) | A throwaway mock backend the reference plugin reads/writes — stdlib-only, in-memory, no auth. Stands in for your real service so `docker compose up` shows the plugin working out of the box; in production you point `SCHEDULING_UPSTREAM` at the real thing instead. |
+| [`shifts-upstream/`](shifts-upstream/) | — (dev service) | A throwaway mock backend the reference plugin reads/writes — stdlib-only, in-memory, no auth. Stands in for your real service so `docker compose up` shows the plugin working out of the box; in production you point `PLUGIN_SETTING_SCHEDULING_UPSTREAM` at the real thing instead. |
@@ -0,0 +1,55 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import type { PageChrome, PluginSettings } from "@plainpages/plugin-api";
+import { buildPluginSettingsModel } from "./admin-plugin-settings.ts";
+
+const CHROME: PageChrome = { brand: { name: "Test" }, csrfToken: "tok", nav: [], signInHref: "/login", user: { email: "", initials: "T", name: "Tester" } };
+
+const CATALOG: readonly PluginSettings[] = [
+  {
+    pluginId: "scheduling",
+    settings: [
+      { description: "Where shifts come from", envName: "PLUGIN_SETTING_SCHEDULING_UPSTREAM", key: "upstream", required: true, secret: false, source: "env", type: "url", value: "https://shifts.test" },
+      { envName: "PLUGIN_SETTING_SCHEDULING_MODE", key: "mode", required: false, secret: false, source: "default", type: "enum", value: "strict", values: ["strict", "lenient"] },
+      { envName: "PLUGIN_SETTING_SCHEDULING_NOTE", key: "note", required: false, secret: false, source: "unset", type: "string" },
+    ],
+  },
+  { pluginId: "quiet", settings: [] },
+];
+
+test("a row carries the variable to set and where the value came from", () => {
+  const model = buildPluginSettingsModel({ chrome: CHROME, settings: CATALOG });
+  const rows = model.groups[0]?.table.rows ?? [];
+  assert.deepEqual(rows.map((r) => r.name), ["upstream", "mode", "note"]);
+  assert.deepEqual(rows[0]?.cells, [
+    { rowHeader: { text: "upstream" } }, "Where shifts come from", "url", "Yes", "PLUGIN_SETTING_SCHEDULING_UPSTREAM", "Environment", "https://shifts.test",
+  ]);
+  assert.equal(rows[1]?.cells[2], "enum (strict, lenient)"); // the choices are the useful half of the type
+  assert.equal(rows[2]?.cells[5], "Not set");
+});
+
+test("a plugin declaring nothing still gets a section, so it is visibly installed", () => {
+  const model = buildPluginSettingsModel({ chrome: CHROME, settings: CATALOG });
+  assert.deepEqual(model.groups.map((g) => g.pluginId), ["scheduling", "quiet"]);
+  assert.deepEqual(model.groups[1]?.table.rows, []);
+  assert.match(model.groups[1]?.emptyText ?? "", /no settings/i);
+});
+
+test("a secret renders as set-or-not, never as a value, a mask or a length", () => {
+  const settings: readonly PluginSettings[] = [{
+    pluginId: "billing",
+    settings: [
+      { envName: "PLUGIN_SETTING_BILLING_API_KEY", key: "apiKey", required: false, secret: true, source: "env", type: "string" },
+      { envName: "PLUGIN_SETTING_BILLING_WEBHOOK_KEY", key: "webhookKey", required: false, secret: true, source: "unset", type: "string" },
+    ],
+  }];
+  const rows = buildPluginSettingsModel({ chrome: CHROME, settings }).groups[0]?.table.rows ?? [];
+  assert.equal(rows[0]?.cells[6], "Secret — set");
+  assert.equal(rows[1]?.cells[6], "Secret — not set");
+});
+
+test("two tables on one page need distinct row-action id stems", () => {
+  const model = buildPluginSettingsModel({ chrome: CHROME, settings: CATALOG });
+  const stems = model.groups.map((g) => g.table.actionsId);
+  assert.equal(new Set(stems).size, stems.length);
+});
@@ -0,0 +1,75 @@
+// Plugin settings admin screen: what each installed plugin declares it can be configured with, the
+// variable that sets it, and how each key resolved. Read-only — the host reads settings from the
+// environment at boot, so changing one is a deploy, not a form.
+
+import { type PageChrome, type PluginSettings, type RouteHandler, type SettingSummary, type Translate } from "@plainpages/plugin-api";
+import { ADMIN_EN, requirePermission } from "./admin-shared.ts";
+
+interface SettingsGroup {
+  emptyText: string;
+  pluginId: string;
+  table: {
+    actionsId: string;
+    caption: string;
+    columns: { label: string }[];
+    rows: { cells: (string | { rowHeader: { text: string } })[]; name: string }[];
+  };
+}
+
+// One group per installed plugin, including those declaring nothing — an operator who cannot find
+// their plugin here has not installed it, which is the other half of what this screen answers.
+export function buildPluginSettingsModel(opts: { chrome: PageChrome; settings: readonly PluginSettings[]; t?: Translate }) {
+  const t = opts.t ?? ADMIN_EN;
+  return {
+    breadcrumbs: [{ label: t("admin.pluginSettings.title") }],
+    chrome: opts.chrome,
+    groups: opts.settings.map((plugin): SettingsGroup => ({
+      emptyText: t("admin.pluginSettings.none"),
+      pluginId: plugin.pluginId,
+      table: {
+        actionsId: `settings-${plugin.pluginId}`, // two tables share this page, so the stem must differ
+        caption: t("admin.pluginSettings.caption", { plugin: plugin.pluginId }),
+        columns: [
+          { label: t("admin.pluginSettings.column.key") },
+          { label: t("admin.pluginSettings.column.description") },
+          { label: t("admin.pluginSettings.column.type") },
+          { label: t("admin.pluginSettings.column.required") },
+          { label: t("admin.pluginSettings.column.variable") },
+          { label: t("admin.pluginSettings.column.source") },
+          { label: t("admin.pluginSettings.column.value") },
+        ],
+        rows: plugin.settings.map((setting) => ({
+          cells: [
+            { rowHeader: { text: setting.key } },
+            setting.description ?? "",
+            typeLabel(setting),
+            t(setting.required ? "admin.pluginSettings.yes" : "admin.pluginSettings.no"),
+            setting.envName,
+            t(`admin.pluginSettings.source.${setting.source}`),
+            valueLabel(setting, t),
+          ],
+          name: setting.key,
+        })),
+      },
+    })),
+    title: t("admin.pluginSettings.title"),
+  };
+}
+
+// An enum's choices are the useful half of its type — they are what the operator must pick from.
+function typeLabel(setting: SettingSummary): string {
+  return setting.type === "enum" && setting.values ? `${setting.type} (${setting.values.join(", ")})` : setting.type;
+}
+
+// A secret never renders its value — not the value, not a mask of it, not its length. Whether it
+// resolved and from where is what an operator needs, and the source column already says the rest.
+function valueLabel(setting: SettingSummary, t: Translate): string {
+  if (setting.secret) return t(setting.source === "unset" ? "admin.pluginSettings.secretUnset" : "admin.pluginSettings.secretSet");
+  return setting.value ?? t("admin.pluginSettings.unset");
+}
+
+// GET /admin/plugin-settings
+export const pluginSettingsList: RouteHandler = (ctx) => {
+  requirePermission(ctx, "plugin-settings");
+  return { data: { chrome: ctx.chrome, model: buildPluginSettingsModel({ chrome: ctx.chrome, settings: ctx.declaredSettings, t: ctx.t }) }, view: "plugin-settings" };
+};
@@ -19,7 +19,7 @@ function fakeCtx(opts: { body?: string; method?: string; user?: User | null; ver
  const req = Readable.from(opts.body != null ? [Buffer.from(opts.body)] : []) as unknown as IncomingMessage;
  req.method = opts.method ?? "GET";
  return {
-    chrome: CHROME, declaredPermissions: [], user: opts.user ?? null, locale: "en-US", localeHref: (href) => href, locales: ["en-US"], log: {} as Log, params: {},
+    chrome: CHROME, declaredPermissions: [], declaredSettings: [], user: opts.user ?? null, locale: "en-US", localeHref: (href) => href, locales: ["en-US"], log: {} as Log, params: {},
    query: url.searchParams, req, res: {} as ServerResponse, permissions: opts.user?.permissions ?? [], t: ADMIN_EN, url,
    verifyCsrf: opts.verifyCsrf ?? (() => true),
  };
@@ -27,21 +27,21 @@ function fakeCtx(opts: { body?: string; method?: string; user?: User | null; ver

 // ---- nav fragment ----

-test("ADMIN_NAV: an ungated Admin header whose three screens each gate on their own read permission", () => {
+test("ADMIN_NAV: an ungated Admin header whose screens each gate on their own read permission", () => {
  assert.equal(ADMIN_NAV.id, "admin");
  // No gate on the header: a user may hold one screen's permission and not another's. composeNav
-  // drops a header left with no visible children, so holding none of the three hides the section.
+  // drops a header left with no visible children, so holding none of them hides the section.
  // Both halves matter — give the header an `href` and it survives the filter as a visible leaf,
  // ungated, for anonymous visitors included.
  assert.equal(ADMIN_NAV.permission, undefined);
  assert.equal(ADMIN_NAV.href, undefined);
  assert.equal(ADMIN_NAV.open, undefined); // the host current-marks + opens; the fragment stays static
-  assert.deepEqual(ADMIN_NAV.children?.map((c) => c.href), ["/admin/users", "/admin/groups", "/admin/clients"]);
-  assert.deepEqual(ADMIN_NAV.children?.map((c) => c.permission), ["users:read", "groups:read", "oauth2-clients:read"]);
+  assert.deepEqual(ADMIN_NAV.children?.map((c) => c.href), ["/admin/users", "/admin/groups", "/admin/clients", "/admin/plugin-settings"]);
+  assert.deepEqual(ADMIN_NAV.children?.map((c) => c.permission), ["users:read", "groups:read", "oauth2-clients:read", "plugin-settings:read"]);
  // Labels are catalog keys; the host translates them with this plugin's catalog when it composes
  // the menu, so what a visitor sees is the en-US (or sv-SE …) wording behind these keys.
-  assert.deepEqual(ADMIN_NAV.children?.map((c) => c.label), ["admin.nav.users", "admin.nav.groups", "admin.nav.clients"]);
-  assert.deepEqual(ADMIN_NAV.children?.map((c) => ADMIN_EN(c.label)), ["Users", "Groups", "OAuth2 clients"]);
+  assert.deepEqual(ADMIN_NAV.children?.map((c) => c.label), ["admin.nav.users", "admin.nav.groups", "admin.nav.clients", "admin.nav.pluginSettings"]);
+  assert.deepEqual(ADMIN_NAV.children?.map((c) => ADMIN_EN(c.label)), ["Users", "Groups", "OAuth2 clients", "Plugin settings"]);
  assert.ok(ADMIN_NAV.children?.every((c) => c.current === undefined));
 });

@@ -12,12 +12,13 @@ export const ADMIN_EN: Translate = englishTranslator(enUS);
 export const ADMIN_USERS_BASE = "/admin/users";
 export const ADMIN_GROUPS_BASE = "/admin/groups";
 export const ADMIN_CLIENTS_BASE = "/admin/clients";
+export const ADMIN_PLUGIN_SETTINGS_BASE = "/admin/plugin-settings";

 // One resource per screen — the `<resource>` half of every permission this plugin gates on.
 // `oauth2-clients` rather than `clients` because permission names are one global namespace.
 // There is no `permissions` resource: permissions are declared in plugin code, not created here, so
 // holding a grant is a property of a user or a group and is edited on those two screens.
-export type AdminResource = "groups" | "oauth2-clients" | "users";
+export type AdminResource = "groups" | "oauth2-clients" | "plugin-settings" | "users";

 export type AdminAction = "read" | "write";

@@ -43,6 +44,7 @@ export const ADMIN_NAV: NavNode = {
    { href: ADMIN_USERS_BASE, icon: "i-users", id: "users", label: "admin.nav.users", permission: permissionName("users", "read") },
    { href: ADMIN_GROUPS_BASE, icon: "i-layers", id: "groups", label: "admin.nav.groups", permission: permissionName("groups", "read") },
    { href: ADMIN_CLIENTS_BASE, icon: "i-globe", id: "clients", label: "admin.nav.clients", permission: permissionName("oauth2-clients", "read") },
+    { href: ADMIN_PLUGIN_SETTINGS_BASE, icon: "i-sliders", id: "plugin-settings", label: "admin.nav.pluginSettings", permission: permissionName("plugin-settings", "read") },
  ],
  icon: "i-shield",
  id: "admin",
@@ -83,9 +83,29 @@ const messages = {

  "admin.nav.clients": "OAuth2 clients",
  "admin.nav.groups": "Groups",
+  "admin.nav.pluginSettings": "Plugin settings",
  "admin.nav.section": "Admin",
  "admin.nav.users": "Users",

+  "admin.pluginSettings.caption": "Settings declared by {{plugin}}",
+  "admin.pluginSettings.column.description": "Description",
+  "admin.pluginSettings.column.key": "Key",
+  "admin.pluginSettings.column.required": "Required",
+  "admin.pluginSettings.column.source": "Source",
+  "admin.pluginSettings.column.type": "Type",
+  "admin.pluginSettings.column.value": "Value",
+  "admin.pluginSettings.column.variable": "Variable",
+  "admin.pluginSettings.no": "No",
+  "admin.pluginSettings.none": "This plugin declares no settings.",
+  "admin.pluginSettings.secretSet": "Secret — set",
+  "admin.pluginSettings.secretUnset": "Secret — not set",
+  "admin.pluginSettings.source.default": "Default",
+  "admin.pluginSettings.source.env": "Environment",
+  "admin.pluginSettings.source.unset": "Not set",
+  "admin.pluginSettings.title": "Plugin settings",
+  "admin.pluginSettings.unset": "—",
+  "admin.pluginSettings.yes": "Yes",
+
  "admin.notFound.message": "That item doesn't exist.",
  "admin.notFound.title": "Not found",

@@ -83,9 +83,29 @@ const messages: AdminMessages = {

  "admin.nav.clients": "OAuth2-klienter",
  "admin.nav.groups": "Grupper",
+  "admin.nav.pluginSettings": "Tilläggsinställningar",
  "admin.nav.section": "Administration",
  "admin.nav.users": "Användare",

+  "admin.pluginSettings.caption": "Inställningar som {{plugin}} deklarerar",
+  "admin.pluginSettings.column.description": "Beskrivning",
+  "admin.pluginSettings.column.key": "Nyckel",
+  "admin.pluginSettings.column.required": "Obligatorisk",
+  "admin.pluginSettings.column.source": "Källa",
+  "admin.pluginSettings.column.type": "Typ",
+  "admin.pluginSettings.column.value": "Värde",
+  "admin.pluginSettings.column.variable": "Variabel",
+  "admin.pluginSettings.no": "Nej",
+  "admin.pluginSettings.none": "Det här tillägget deklarerar inga inställningar.",
+  "admin.pluginSettings.secretSet": "Hemlighet — satt",
+  "admin.pluginSettings.secretUnset": "Hemlighet — inte satt",
+  "admin.pluginSettings.source.default": "Standardvärde",
+  "admin.pluginSettings.source.env": "Miljövariabel",
+  "admin.pluginSettings.source.unset": "Inte satt",
+  "admin.pluginSettings.title": "Tilläggsinställningar",
+  "admin.pluginSettings.unset": "—",
+  "admin.pluginSettings.yes": "Ja",
+
  "admin.notFound.message": "Objektet finns inte.",
  "admin.notFound.title": "Hittades inte",

@@ -35,17 +35,20 @@ test("every nav permission is one the manifest declares", () => {
    }
  };
  walk(manifest.nav);
-  assert.equal(navPermissions.length, 3);
+  assert.equal(navPermissions.length, 4);
  for (const name of navPermissions) assert.ok(declared.includes(name), `nav gates on undeclared ${name}`);
 });

 test("every declared permission is <resource>:<action>, and reads and writes are split per resource", () => {
  for (const name of declared) assert.ok(isValidPermissionName(name), name); // the host's rule, not a copy of it
-  // Three screens × read/write. There is deliberately no `permissions:` pair: permissions are
-  // declared in plugin code, so holding one is edited on the user or group that holds it.
+  // Three CRUD screens × read/write, plus read-only plugin settings — a screen that never writes
+  // declares no `:write`, since a permission nothing gates on is one an operator can only mis-grant.
+  // There is deliberately no `permissions:` pair either: permissions are declared in plugin code, so
+  // holding one is edited on the user or group that holds it.
  assert.deepEqual([...declared].sort(), [
    "groups:read", "groups:write",
    "oauth2-clients:read", "oauth2-clients:write",
+    "plugin-settings:read",
    "users:read", "users:write",
  ]);
 });
@@ -58,5 +61,5 @@ test("GET routes gate on read and mutations on write, so a reader can open a scr
    const action = route.method === "GET" && !writeIntent(route.path) ? "read" : "write";
    assert.ok(route.permission?.endsWith(`:${action}`), `${route.method} ${route.path} → ${route.permission}`);
  }
-  assert.equal(routes.filter((r) => r.method === "GET" && writeIntent(r.path)).length, 6); // 2 per screen
+  assert.equal(routes.filter((r) => r.method === "GET" && writeIntent(r.path)).length, 6); // 2 per CRUD screen; plugin settings has none
 });
@@ -7,6 +7,7 @@
 import { definePlugin, type HttpMethod, type Route, type RouteHandler } from "@plainpages/plugin-api";
 import { clientsCreate, clientsDeleteConfirm, clientsDelete, clientsDetail, clientsList, clientsNewForm } from "./admin-clients.ts";
 import { groupsAddMember, groupsCreate, groupsDelete, groupsDeleteConfirm, groupsDetail, groupsList, groupsNewForm, groupsPermissions, groupsRemoveMember } from "./admin-groups.ts";
+import { pluginSettingsList } from "./admin-plugin-settings.ts";
 import { usersCreate, usersDeleteConfirm, usersDelete, usersEditForm, usersList, usersNewForm, usersPermissions, usersRecovery, usersState, usersUpdate } from "./admin-users.ts";
 import { ADMIN_NAV, actionForMethod, type AdminAction, type AdminResource, permissionName } from "./admin-shared.ts";

@@ -24,9 +25,10 @@ const on = (resource: AdminResource) => (method: HttpMethod, path: string, handl
 const users = on("users");
 const groups = on("groups");
 const clients = on("oauth2-clients");
+const pluginSettings = on("plugin-settings");

 export default definePlugin({
-  apiVersion: "0.1.0", // the host contract this was built against — a literal, never HOST_API_VERSION
+  apiVersion: "0.2.0", // the host contract this was built against — a literal, never HOST_API_VERSION

  nav: [ADMIN_NAV],

@@ -37,6 +39,7 @@ export default definePlugin({
    { description: "Create and delete groups, and change their members and permissions", name: "groups:write" },
    { description: "View OAuth2 clients", name: "oauth2-clients:read" },
    { description: "Register and delete OAuth2 clients", name: "oauth2-clients:write" },
+    { description: "View the settings each installed plugin declares, and how they resolved", name: "plugin-settings:read" },
  ],

  routes: [
@@ -68,5 +71,7 @@ export default definePlugin({
    clients("GET", "/clients/:id", clientsDetail),
    clients("GET", "/clients/:id/delete", clientsDeleteConfirm, "write"),
    clients("POST", "/clients/:id/delete", clientsDelete),
+    // Plugin settings — read-only, so no :write route and no write-intent GET.
+    pluginSettings("GET", "/plugin-settings", pluginSettingsList),
  ],
 });
@@ -0,0 +1,24 @@
+<%#
+  Plugin settings admin list: one section per installed plugin, each a table of what it declares
+  and how each key resolved (admin-plugin-settings.ts). Read-only — no actions, no forms.
+%><%
+  const nav = include("partials/nav-tree", { nodes: chrome.nav });
+  let body = "";
+  for (const group of model.groups) {
+    // A plugin id is the folder name, which discovery constrains to [a-z0-9-] — no escaping needed.
+    body += '<h2 class="h2">' + group.pluginId + "</h2>";
+    body += group.table.rows.length === 0
+      ? '<p class="muted">' + group.emptyText + "</p>"
+      : include("partials/data-table", group.table);
+  }
+-%>
+<%- include("partials/shell", {
+  body,
+  brand: chrome.brand,
+  breadcrumbs: model.breadcrumbs,
+  csrfToken: chrome.csrfToken,
+  nav,
+  theme: chrome.theme,
+  title: model.title,
+  user: chrome.user,
+}) %>
@@ -27,7 +27,7 @@ The plugin holds **no state** — data lives upstream (README → *Stateless*).

 ## Upstream

-Set `SCHEDULING_UPSTREAM` to your backend's base URL. The dev compose points it at a tiny in-memory
+Set `PLUGIN_SETTING_SCHEDULING_UPSTREAM` to your backend's base URL. The dev compose points it at a tiny in-memory
 mock (`examples/shifts-upstream/`) so `docker compose up` shows the plugin working out of the box.
 A malformed/non-http URL fails the boot loudly (the plugin's `onBoot` hook).

@@ -3,19 +3,20 @@
 // folder, rename it, point it at your own backend. Full contract: README.md → Building plugins.

 import { definePlugin } from "@plainpages/plugin-api";
-import { assertHttpUrl, createShift, createUpstream, listShifts, newShiftForm, overview, READ, SCHEDULING_PATH, SHIFTS_PATH, WRITE } from "./shifts.ts";
+import { createShift, createUpstream, listShifts, newShiftForm, overview, READ, SCHEDULING_PATH, SHIFTS_PATH, WRITE } from "./shifts.ts";

 // The upstream this plugin reads/writes — a stand-in for your real backend (the plugin is
-// stateless). Configure via env; the dev compose points it at a tiny mock (examples/shifts-upstream).
-const upstreamUrl = process.env["SCHEDULING_UPSTREAM"] ?? "http://shifts-upstream:4000";
-const upstream = createUpstream(upstreamUrl);
+// stateless). Its URL is a declared setting, so it is resolved and validated before onBoot hands it
+// over — which is after this manifest is built, hence the getter.
+let upstreamUrl = "";
+const upstream = createUpstream(() => upstreamUrl);

 export default definePlugin({
-  apiVersion: "0.1.0", // the host contract this was built against — a literal, never HOST_API_VERSION
+  apiVersion: "0.2.0", // the host contract this was built against — a literal, never HOST_API_VERSION

-  // onBoot runs after discovery, before the server listens: validate the plugin's own config so a
-  // typo'd SCHEDULING_UPSTREAM fails the boot loudly instead of degrading every request later.
-  hooks: { onBoot: () => assertHttpUrl(upstreamUrl, "SCHEDULING_UPSTREAM") },
+  // onBoot runs after discovery, before the server listens — where a plugin receives its resolved
+  // settings. A malformed URL already failed the boot by then; the host validated the declared type.
+  hooks: { onBoot: ({ settings }) => { upstreamUrl = settings.upstream; } },

  // Merged into the global menu + filtered per user. Labels are keys in this plugin's own catalog
  // (i18n/<locale>.ts) — a plain string works too, it just isn't translated. "Overview" is `public`, so the "Scheduling"
@@ -45,4 +46,15 @@ export default definePlugin({
    { handler: newShiftForm(), method: "GET", path: "/shifts/new", permission: WRITE },
    { handler: createShift(upstream), method: "POST", path: "/shifts", permission: WRITE },
  ],
+
+  // Operator-supplied config: one PLUGIN_SETTING_SCHEDULING_UPSTREAM variable, validated as a URL at
+  // boot. The default points at the mock backend the dev compose runs (examples/shifts-upstream).
+  settings: [
+    {
+      default: "http://shifts-upstream:4000",
+      description: "Base URL of the backend this plugin reads shifts from and writes them to",
+      key: "upstream",
+      type: "url",
+    },
+  ],
 });
@@ -7,7 +7,7 @@ import test from "node:test";
 import { englishTranslator, GuardError, Log, type PageChrome, type RequestContext, type RouteResult } from "@plainpages/plugin-api";
 import enUS from "./i18n/en-US.ts";
 import {
-  assertHttpUrl, buildFormModel, createShift, createUpstream, listShifts, newShiftForm, overview, readInput,
+  buildFormModel, createShift, createUpstream, listShifts, newShiftForm, overview, readInput,
  SHIFTS_PATH, type Shift, type ShiftInput, type ShiftsUpstream, UpstreamError, validate,
 } from "./shifts.ts";

@@ -18,7 +18,7 @@ function fakeCtx(opts: { body?: string; permissions?: string[]; url?: string; ve
  const url = new URL(opts.url ?? "http://localhost/scheduling/shifts");
  const req = Readable.from(opts.body != null ? [Buffer.from(opts.body)] : []) as unknown as IncomingMessage;
  return {
-    chrome: CHROME, declaredPermissions: [], user: null, locale: "en-US", localeHref: (href) => href, locales: ["en-US"], log: new Log("none"), params: {},
+    chrome: CHROME, declaredPermissions: [], declaredSettings: [], user: null, locale: "en-US", localeHref: (href) => href, locales: ["en-US"], log: new Log("none"), params: {},
    query: url.searchParams, req, res: {} as ServerResponse, permissions: opts.permissions ?? [], t, url,
    verifyCsrf: opts.verifyCsrf ?? (() => true),
  };
@@ -35,27 +35,25 @@ const asView = (r: RouteResult | void) => {
  return r as { data: Record<string, unknown>; status?: number; view: string };
 };

-// ---- upstream config validation (the onBoot hook) ----
+// ---- the upstream URL as a declared setting ----

-test("assertHttpUrl accepts http(s) and fails loud on a malformed or non-http upstream URL", () => {
-  assert.doesNotThrow(() => assertHttpUrl("http://shifts-upstream:4000", "SCHEDULING_UPSTREAM"));
-  assert.doesNotThrow(() => assertHttpUrl("https://api.example.com/v1", "SCHEDULING_UPSTREAM"));
-  assert.throws(() => assertHttpUrl("not a url", "SCHEDULING_UPSTREAM"), /SCHEDULING_UPSTREAM.*valid URL/); // unparseable
-  assert.throws(() => assertHttpUrl("shifts-upstream:4000", "SCHEDULING_UPSTREAM"), /SCHEDULING_UPSTREAM.*http/); // missing // → parsed as a bogus scheme
-  assert.throws(() => assertHttpUrl("ftp://host/x", "SCHEDULING_UPSTREAM"), /SCHEDULING_UPSTREAM.*http/); // wrong scheme
+test("the manifest declares its upstream as a URL setting the host validates", async () => {
+  const manifest = (await import("./plugin.ts")).default;
+  assert.deepEqual(manifest.settings?.map((s) => s.key), ["upstream"]);
+  assert.equal(manifest.settings?.[0]?.type, "url"); // so a typo'd URL fails the boot, not every request
+  assert.equal(manifest.settings?.[0]?.default, "http://shifts-upstream:4000"); // the dev compose's mock
+  assert.equal(typeof manifest.hooks?.onBoot, "function"); // without it the resolved value never arrives
 });

-test("the manifest's onBoot hook validates SCHEDULING_UPSTREAM (the binding, not just the helper)", async () => {
-  const prev = process.env["SCHEDULING_UPSTREAM"];
-  process.env["SCHEDULING_UPSTREAM"] = "nope://bad"; // read at import time below
-  try {
-    const manifest = (await import("./plugin.ts")).default;
-    assert.equal(typeof manifest.hooks?.onBoot, "function");
-    assert.throws(() => manifest.hooks!.onBoot!({}), /SCHEDULING_UPSTREAM/); // bad upstream → boot fails loud
-  } finally {
-    if (prev === undefined) delete process.env["SCHEDULING_UPSTREAM"];
-    else process.env["SCHEDULING_UPSTREAM"] = prev;
-  }
+test("the client re-reads its base URL, so onBoot can bind it after the manifest is built", async () => {
+  let baseUrl = "http://first:4000";
+  const seen: string[] = [];
+  const http = (async (url) => { seen.push(String(url)); return new Response("[]", { status: 200 }); }) as typeof fetch;
+  const upstream = createUpstream(() => baseUrl, http);
+  await upstream.list();
+  baseUrl = "http://second:4000";
+  await upstream.list();
+  assert.deepEqual(seen, ["http://first:4000/shifts", "http://second:4000/shifts"]);
 });

 // ---- upstream client (fetch injected) ----
@@ -67,21 +65,21 @@ test("createUpstream.list fetches /shifts, asks for JSON, and maps the rows", as
    assert.equal((init?.headers as Record<string, string>).accept, "application/json");
    return new Response(JSON.stringify([{ assignee: "A", end: "2", id: "x", start: "1", title: "T", extra: "ignored" }]), { status: 200 });
  }) as typeof fetch;
-  const shifts = await createUpstream("http://up:4000/", http).list(); // trailing slash trimmed
+  const shifts = await createUpstream(() => "http://up:4000/", http).list(); // trailing slash trimmed
  assert.equal(seen, "http://up:4000/shifts");
  assert.deepEqual(shifts, [{ assignee: "A", end: "2", id: "x", start: "1", title: "T" }]);
 });

 test("createUpstream throws UpstreamError carrying the status on a non-2xx", async () => {
  const http = (async () => new Response("nope", { status: 503 })) as typeof fetch;
-  await assert.rejects(createUpstream("http://up:4000", http).list(), (e: unknown) => e instanceof UpstreamError && e.status === 503);
+  await assert.rejects(createUpstream(() => "http://up:4000", http).list(), (e: unknown) => e instanceof UpstreamError && e.status === 503);
 });

 test("createUpstream.create POSTs the input as JSON", async () => {
  let body: unknown, method = "";
  const http = (async (_url, init) => { method = init?.method ?? ""; body = JSON.parse(String(init?.body)); return new Response(null, { status: 201 }); }) as typeof fetch;
  const input: ShiftInput = { assignee: "A", end: "2", start: "1", title: "T" };
-  await createUpstream("http://up:4000", http).create(input);
+  await createUpstream(() => "http://up:4000", http).create(input);
  assert.equal(method, "POST");
  assert.deepEqual(body, input);
 });
@@ -49,26 +49,16 @@ export interface ShiftsUpstream {
  list(): Promise<Shift[]>;
 }

-// Fail loud at boot (the plugin's onBoot hook) on a malformed/non-http upstream URL — a config
-// typo surfaces at startup, not as a degraded page later. Reachability stays a runtime concern.
-export function assertHttpUrl(value: string, name: string): void {
-  let url: URL;
-  try {
-    url = new URL(value);
-  } catch {
-    throw new Error(`${name} is not a valid URL: ${JSON.stringify(value)}`);
-  }
-  if (url.protocol !== "http:" && url.protocol !== "https:") throw new Error(`${name} must be an http(s) URL: ${JSON.stringify(value)}`);
-}
-
 // REST client over the upstream service (a stand-in for the customer's real backend). `fetch`
 // defaults to the host's tracedFetch, so each upstream call joins the request's trace (a client
 // span + a propagated traceparent); it's injectable so handlers unit-test against a mock, no network.
-export function createUpstream(baseUrl: string, fetchImpl: typeof fetch = tracedFetch): ShiftsUpstream {
-  const base = baseUrl.replace(/\/+$/, "");
+// `baseUrl` is read per call: the plugin's settings arrive on onBoot, after the manifest that binds
+// these handlers has already been built.
+export function createUpstream(baseUrl: () => string, fetchImpl: typeof fetch = tracedFetch): ShiftsUpstream {
+  const base = (): string => baseUrl().replace(/\/+$/, "");
  return {
    async create(input) {
-      const res = await fetchImpl(`${base}/shifts`, {
+      const res = await fetchImpl(`${base()}/shifts`, {
        body: JSON.stringify(input),
        headers: { "content-type": "application/json" },
        method: "POST",
@@ -76,7 +66,7 @@ export function createUpstream(baseUrl: string, fetchImpl: typeof fetch = traced
      if (!res.ok) throw new UpstreamError(`create shift failed (${res.status})`, res.status);
    },
    async list() {
-      const res = await fetchImpl(`${base}/shifts`, { headers: { accept: "application/json" } });
+      const res = await fetchImpl(`${base()}/shifts`, { headers: { accept: "application/json" } });
      if (!res.ok) throw new UpstreamError(`list shifts failed (${res.status})`, res.status);
      const data: unknown = await res.json();
      return Array.isArray(data) ? data.map(toShift) : [];
@@ -1,6 +1,6 @@
 // Dev-only mock upstream for the reference plugin (examples/plugins/scheduling) — a stand-in for the
 // customer's real backend, ready for when you copy the reference plugin into plugins/. NOT part
-// of the app: stdlib only, in-memory (state resets on restart), no auth. Point SCHEDULING_UPSTREAM
+// of the app: stdlib only, in-memory (state resets on restart), no auth. Point PLUGIN_SETTING_SCHEDULING_UPSTREAM
 // at your real service in production.
 //
 //   GET  /shifts  → 200 [ { id, title, assignee, start, end }, … ]
@@ -12,7 +12,7 @@ test("readHostApiVersion pulls the constant out of the real source, and returns
 test("bumping HOST_API_VERSION is a deliberate act, so pin the shipped value", () => {
  // Not a substitute for the release gate — this test cannot see a tag. It is the tripwire that
  // makes an accidental edit fail here rather than at release time.
-  assert.equal(readHostApiVersion(readFileSync("src/plugin-host/plugin.ts", "utf8")), "0.1.0");
+  assert.equal(readHostApiVersion(readFileSync("src/plugin-host/plugin.ts", "utf8")), "0.2.0");
 });

 test("every author-facing apiVersion sample matches the shipped contract", () => {
@@ -182,7 +182,7 @@ into the app. Create `plugins/hello/plugin.ts`:
 import { definePlugin } from "@plainpages/plugin-api";

 export default definePlugin({
-  apiVersion: "0.1.0",
+  apiVersion: "0.2.0",
  nav: [{ href: "/hello", id: "hello", label: "Hello", public: true }],
  routes: [
    { method: "GET", path: "/", public: true, handler: () => ({ html: "<h1>Hello from my plugin</h1>" }) },
@@ -56,6 +56,7 @@ export interface Config {
  pluginDbSecret: string; // derives each plugin's database password (src/plugin-host/storage.ts)
  pluginDbUrl: string | undefined; // credential-free Postgres base URL; unset ⇒ plugin storage is off
  port: number;
+  requireSecureSecrets: boolean; // enforce real secrets — the host's own, and every plugin's declared `secret`
  revocationDenylist: boolean; // enable the optional instant permission/session revoke denylist
  revocationTtlSec: number; // how long a revoke entry lives; keep ≥ tokenizer TTL + clock skew
  secureCookies: boolean;
@@ -188,6 +189,7 @@ export function loadConfig(env: Env = process.env): Config {
    pluginDbSecret: resolvePluginDbSecret(env, requireSecure && Boolean(env["PLUGIN_DB_URL"])),
    pluginDbUrl: readCredentiallessUrl(env, "PLUGIN_DB_URL"),
    port: readPort(env),
+    requireSecureSecrets: requireSecure,
    // Optional instant-revoke, off by default. When on, an admin deactivate/delete or permission
    // change revokes the subject's live tokens at once; the entry lives ttl seconds (≥ the 10m
    // tokenizer TTL + skew, so it outlasts any pre-revoke token).
@@ -26,6 +26,7 @@ import { createLogger, type Log, requestLogger, runWithLog } from "../logger.ts"
 import { remintSession } from "../auth/login.ts";
 import { DEFAULT_MENU, type MenuConfig } from "../ui/menu-config.ts";
 import { declaredPermissions, type Plugin, type RouteHandler, type RouteResult } from "../plugin-host/plugin.ts";
+import type { PluginSettings } from "../plugin-host/settings.ts";
 import type { SystemCapabilities } from "../plugin-host/system.ts";
 import { allowedMethods, isAuthorized, matchRoute } from "../plugin-host/router.ts";
 import { buildAuthRoutes } from "../auth/routes.ts";
@@ -54,6 +55,7 @@ export interface AppOptions {
  pluginsDir?: string; // where plugin views/static live; defaults to the scanned plugins/
  publicDir?: string;
  secureCookies?: boolean; // set Secure on our session/CSRF cookies (config.secureCookies; off in dev http)
+  settingsCatalog?: readonly PluginSettings[]; // resolved at boot (server.ts, needs the env); → ctx.declaredSettings
  viewsDir?: string;
 }

@@ -88,6 +90,7 @@ export function createApp(options: AppOptions = {}): Server {
  const homePlugin = plugins.find((p): p is Plugin & { home: RouteHandler } => typeof p.home === "function");
  const dashboardPlugin = plugins.find((p): p is Plugin & { dashboard: RouteHandler } => typeof p.dashboard === "function");
  const permissionCatalog = declaredPermissions(plugins);
+  const settingsCatalog = options.settingsCatalog ?? [];
  // Skip the hook pipeline entirely unless a plugin declares the hook (keeps the hot path free).
  const anyRequestHooks = plugins.some((p) => p.hooks?.onRequest);
  const anyResponseHooks = plugins.some((p) => p.hooks?.onResponse);
@@ -259,9 +262,9 @@ export function createApp(options: AppOptions = {}): Server {

      // Base context (no route params), for the built-in routes. Every plugin-owned render — a
      // landing slot, a hook short-circuit, a plugin route — gets `contextFor(id)` instead.
-      const ctx = buildContext(req, res, { chrome, declaredPermissions: permissionCatalog, user, ...i18nFor(), log: reqLog, verifyCsrf, ...(system ? { system } : {}) });
+      const ctx = buildContext(req, res, { chrome, declaredPermissions: permissionCatalog, declaredSettings: settingsCatalog, user, ...i18nFor(), log: reqLog, verifyCsrf, ...(system ? { system } : {}) });
      const contextFor = (pluginId: string, params?: Record<string, string>): RequestContext =>
-        buildContext(req, res, { chrome, declaredPermissions: permissionCatalog, user, ...i18nFor(pluginId), log: reqLog, ...(params ? { params } : {}), verifyCsrf, ...(system ? { system } : {}) });
+        buildContext(req, res, { chrome, declaredPermissions: permissionCatalog, declaredSettings: settingsCatalog, user, ...i18nFor(pluginId), log: reqLog, ...(params ? { params } : {}), verifyCsrf, ...(system ? { system } : {}) });
      renderPage = viewsFor(ctx);

      // Plugin onRequest hooks run before routing and may short-circuit the request.
@@ -1,6 +1,7 @@
 import type { IncomingMessage, ServerResponse } from "node:http";
 import type { PageChrome } from "../ui/chrome.ts"; // type-only: no runtime import, so no cycle
 import type { PermissionDecl } from "../plugin-host/plugin.ts"; // type-only
+import type { PluginSettings } from "../plugin-host/settings.ts"; // type-only
 import type { SystemCapabilities } from "../plugin-host/system.ts"; // type-only
 import { DEFAULT_LOCALE } from "../i18n/catalog.ts";
 import { ENGLISH } from "../i18n/english.ts";
@@ -42,6 +43,9 @@ export interface RequestContext {
  // screen offers when granting one. Pairs with `permissions` below: this is what *exists*, that is
  // what *this user holds*. Empty when no installed plugin declares any.
  declaredPermissions: readonly PermissionDecl[];
+  // What each installed plugin declares it can be configured with, and how each key resolved — one
+  // entry per plugin, including those declaring nothing. A secret's value is never carried here.
+  declaredSettings: readonly PluginSettings[];
  params: Record<string, string>; // path params from the route match, e.g. /users/:id → { id }
  permissions: string[]; // user?.permissions ?? [] — coarse gate without a null-check
  query: URLSearchParams; // alias of url.searchParams, for ctx.query.get("q")
@@ -67,6 +71,7 @@ export interface BuildContextOptions {
  // The host's factory is memoised, so the menu composes at most once per request across contexts.
  chrome?: () => PageChrome;
  declaredPermissions?: readonly PermissionDecl[];
+  declaredSettings?: readonly PluginSettings[];
  user?: User | null;
  locale?: string;
  localeHref?: (href: string) => string;
@@ -96,6 +101,7 @@ export function buildContext(
  return {
    get chrome(): PageChrome { return (chromeMemo ??= buildChrome ? buildChrome() : ANON_CHROME); },
    declaredPermissions: options.declaredPermissions ?? [],
+    declaredSettings: options.declaredSettings ?? [],
    user,
    locale: options.locale ?? DEFAULT_LOCALE,
    localeHref: options.localeHref ?? ((href) => href),
@@ -8,6 +8,7 @@ import { existsSync, readdirSync, readFileSync } from "node:fs";
 import { dirname, join } from "node:path";
 import { fileURLToPath, pathToFileURL } from "node:url";
 import { checkApiVersion, findConflicts, isValidPermissionName, isValidPluginId, RESERVED_PLUGIN_IDS, type Plugin, type PluginManifest } from "./plugin.ts";
+import { settingsDeclError } from "./settings.ts";
 import { isValidStoragePluginId, MAX_STORAGE_PLUGIN_ID_LENGTH } from "./storage.ts";

 const rootDir = join(dirname(fileURLToPath(import.meta.url)), "..", "..");
@@ -141,6 +142,10 @@ function shapeError(manifest: PluginManifest): string | null {
  }
  // A truthy non-boolean (a DSN, say) must not quietly read as "provision me one".
  if (manifest.storage !== undefined && typeof manifest.storage !== "boolean") return `"storage" must be a boolean`;
+  if (manifest.settings !== undefined) {
+    const settings = settingsDeclError(manifest.settings);
+    if (settings) return settings;
+  }
  // `public` and `permission` are contradictory on the same route/nav node — "open to all" vs
  // "needs this permission". Refuse rather than silently pick one, so the author's intent is unambiguous.
  for (const route of Array.isArray(manifest.routes) ? manifest.routes : []) {
@@ -8,6 +8,7 @@ export { definePlugin, isValidPermissionName } from "./plugin.ts";
 export type { BootContext, HttpMethod, Plugin, PluginHooks, PluginManifest, PermissionDecl, Route, RouteHandler, RouteResult } from "./plugin.ts";
 // A plugin's own database, handed to onBoot when the manifest sets `storage`. Credentials, not a
 // client — the plugin depends on whichever driver it prefers (README → Plugin storage).
+export type { PluginSettings, SettingDecl, SettingSummary, SettingType, SettingValue } from "./settings.ts";
 export type { StorageCredentials } from "./storage.ts";
 export type { RequestContext, User } from "../http/context.ts";
 export type { PageChrome } from "../ui/chrome.ts";
@@ -6,10 +6,11 @@

 import type { RequestContext } from "../http/context.ts";
 import type { NavNode } from "../ui/nav.ts";
+import { envName, type SettingDecl, type SettingsOf } from "./settings.ts";
 import type { StorageCredentials } from "./storage.ts";

 // The Plainpages release this contract ships in — see README → Contract versioning.
-export const HOST_API_VERSION = "0.1.0";
+export const HOST_API_VERSION = "0.2.0";

 export type HttpMethod = "DELETE" | "GET" | "HEAD" | "PATCH" | "POST" | "PUT";

@@ -62,30 +63,39 @@ export function declaredPermissions(plugins: Plugin[]): PermissionDecl[] {
 }

 // What onBoot receives. A hook declaring no parameter stays valid, so this may grow additively.
-export interface BootContext {
+export type BootContext<S extends readonly SettingDecl[] = readonly SettingDecl[]> = {
  storage?: StorageCredentials; // this plugin's own database; present iff the manifest declared `storage`
-}
+} & SettingsSlot<S>;
+
+// Required once the manifest declares settings, so that plugin reads `settings.key` without a guard
+// for the case it just ruled out; optional for a manifest that declared none.
+type SettingsSlot<S extends readonly SettingDecl[]> = readonly [] extends S
+  ? { settings?: SettingsOf<S> }
+  : { settings: SettingsOf<S> };

 // Optional hooks on system actions. Crash-isolation is a non-goal — a throwing hook fails loud.
-export interface PluginHooks {
-  onBoot?: (host: BootContext) => Promise<void> | void; // after discovery, before the server listens
+export interface PluginHooks<S extends readonly SettingDecl[] = readonly SettingDecl[]> {
+  onBoot?: (host: BootContext<S>) => Promise<void> | void; // after discovery, before the server listens
  onRequest?: (ctx: RequestContext) => Promise<RouteResult | void> | RouteResult | void; // may short-circuit
  onResponse?: (ctx: RequestContext, result: RouteResult | null) => Promise<void> | void;
 }

 // The authored manifest — a plugin's `plugin.ts` default-exports this. No `id`/mount path: the
 // host derives them from the folder name at discovery (see Plugin).
-export interface PluginManifest {
+export interface PluginManifest<S extends readonly SettingDecl[] = readonly SettingDecl[]> {
  apiVersion: string; // semver of the host contract this targets — write a literal, NOT HOST_API_VERSION (see docs)
  // Take over "/dashboard"; the host gates it to a signed-in session first. At most one plugin may
  // declare it (findConflicts → error, never last-write-wins).
  dashboard?: RouteHandler;
  // Take over the ungated public landing "/". At most one plugin may declare it.
  home?: RouteHandler;
-  hooks?: PluginHooks;
+  hooks?: PluginHooks<S>;
  nav?: NavNode[]; // fragment merged into the menu (composeNav); node `icon` is a Lucide sprite id (src/ui/icons.ts), node ids must be globally unique
  permissions?: PermissionDecl[];
  routes?: Route[];
+  // Operator-supplied configuration, one PLUGIN_SETTING_<ID>_<KEY> variable per key; the resolved
+  // values arrive on onBoot's BootContext, typed from these declarations (settings.ts).
+  settings?: S;
  // Ask for a Postgres database of this plugin's own; its credentials arrive on onBoot's BootContext.
  // The host provisions and locks it down but owns no schema inside it, and never drops it.
  storage?: boolean;
@@ -99,7 +109,9 @@ export interface Plugin extends PluginManifest {

 // Types the manifest and returns it unchanged; validation happens at discovery, so a plugin may
 // equally be a plain typed object.
-export function definePlugin(manifest: PluginManifest): PluginManifest {
+// The `const` parameter captures the literal `settings`, so onBoot receives each key at its declared
+// type instead of a union every plugin author would have to narrow with a cast.
+export function definePlugin<const S extends readonly SettingDecl[]>(manifest: PluginManifest<S>): PluginManifest<S> {
  return manifest;
 }

@@ -168,7 +180,7 @@ export function checkApiVersion(pluginVersion: unknown, hostVersion: string = HO
 }

 export interface PluginConflict {
-  kind: "dashboard" | "home" | "id" | "nav-id" | "permission" | "route";
+  kind: "dashboard" | "home" | "id" | "nav-id" | "permission" | "route" | "setting";
  level: "error" | "warn";
  message: string;
  plugins: string[]; // unique ids involved
@@ -209,6 +221,14 @@ export function findConflicts(plugins: Plugin[]): PluginConflict[] {
    if (owners.length > 1) out.push({ kind: "permission", level: "warn", message: `permission "${name}" declared by ${uniq(owners).length} plugins; pick a more specific "<resource>" unless shared on purpose`, plugins: uniq(owners) });
  });

+  // Both the id's dashes and the key's camel humps become underscores, so plugin "a-b" key "c" and
+  // plugin "a" key "bC" name one variable — one plugin would silently read the other's value.
+  collect(plugins, (plugin, push) => {
+    for (const decl of plugin.settings ?? []) push(envName(plugin.id, decl.key));
+  }).forEach((owners, name) => {
+    if (owners.length > 1) out.push({ kind: "setting", level: "error", message: `${owners.length} settings resolve to "${name}"; rename a key or a plugin folder`, plugins: uniq(owners) });
+  });
+
  return out;
 }

@@ -0,0 +1,177 @@
+// Guards the plugin-settings rules: the env name a declaration maps to, per-type coercion, the
+// required/default/secret resolution, and what the admin catalog is allowed to carry.
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import type { Plugin } from "./plugin.ts";
+import {
+  ENV_PREFIX,
+  envName,
+  isValidSettingKey,
+  resolveSettings,
+  settingsDeclError,
+  settingsEnvNames,
+  strayNames,
+  type SettingDecl,
+} from "./settings.ts";
+
+function pluginWith(id: string, settings: SettingDecl[]): Plugin {
+  return { apiVersion: "0.2.0", id, settings };
+}
+
+test("a key becomes one SCREAMING_SNAKE segment under the plugin's own", () => {
+  assert.equal(envName("scheduling", "timezone"), "PLUGIN_SETTING_SCHEDULING_TIMEZONE");
+  assert.equal(envName("scheduling", "maxShiftHours"), "PLUGIN_SETTING_SCHEDULING_MAX_SHIFT_HOURS");
+  assert.equal(envName("my-plugin", "apiBase"), "PLUGIN_SETTING_MY_PLUGIN_API_BASE");
+  assert.equal(ENV_PREFIX, "PLUGIN_SETTING_"); // never bare PLUGIN_ — the host owns PLUGIN_DB_*
+});
+
+test("the host's own PLUGIN_DB_* variables are unreachable from a declaration", () => {
+  // A plugin id "db" with key "url" is exactly the collision the longer prefix rules out.
+  assert.notEqual(envName("db", "url"), "PLUGIN_DB_URL");
+  assert.equal(envName("db", "url"), "PLUGIN_SETTING_DB_URL");
+});
+
+test("a key is camelCase, so the env name is derivable and no two keys collide", () => {
+  assert.ok(isValidSettingKey("timezone"));
+  assert.ok(isValidSettingKey("maxShiftHours"));
+  assert.ok(!isValidSettingKey("max_shift_hours")); // would collide with maxShiftHours
+  assert.ok(!isValidSettingKey("MaxShiftHours"));
+  assert.ok(!isValidSettingKey("2fa"));
+  assert.ok(!isValidSettingKey(""));
+});
+
+test("a declaration is refused when it cannot mean what it says", () => {
+  const why = (settings: unknown): string => settingsDeclError(settings) ?? "";
+
+  assert.equal(settingsDeclError([{ key: "a", type: "string" }]), null);
+  assert.match(why("nope"), /must be an array/);
+  assert.match(why([{ key: "max_hours", type: "number" }]), /max_hours.*camelCase/);
+  assert.match(why([{ key: "a", type: "date" }]), /"date".*string, number, boolean, enum, url/);
+  assert.match(why([{ key: "a", type: "string" }, { key: "a", type: "number" }]), /declared twice/);
+  // required means "boot fails without it", so a default would make the flag a lie.
+  assert.match(why([{ default: "x", key: "a", required: true, type: "string" }]), /required.*default.*mutually exclusive/);
+  assert.match(why([{ default: 8, key: "a", type: "string" }]), /default.*string/);
+  assert.match(why([{ key: "a", type: "enum" }]), /enum.*values/);
+  assert.match(why([{ key: "a", type: "enum", values: [] }]), /enum.*values/);
+  assert.match(why([{ default: "c", key: "a", type: "enum", values: ["a", "b"] }]), /default "c".*a, b/);
+  assert.match(why([{ key: "a", type: "string", values: ["a"] }]), /values.*only.*enum/);
+});
+
+test("an unset optional setting resolves to undefined, not to a stand-in", () => {
+  const result = resolveSettings([pluginWith("p", [{ key: "a", type: "string" }])], {});
+  assert.deepEqual(result.errors, []);
+  assert.equal(result.values.get("p")?.["a"], undefined);
+});
+
+test("a default fills in, and an env value overrides it", () => {
+  const plugins = [pluginWith("p", [{ default: 8, key: "maxHours", type: "number" }])];
+  assert.equal(resolveSettings(plugins, {}).values.get("p")?.["maxHours"], 8);
+  assert.equal(resolveSettings(plugins, { PLUGIN_SETTING_P_MAX_HOURS: "12" }).values.get("p")?.["maxHours"], 12);
+});
+
+test("an empty variable reads as unset — compose passes an unset one through as \"\"", () => {
+  const plugins = [pluginWith("p", [{ default: "fallback", key: "a", type: "string" }])];
+  assert.equal(resolveSettings(plugins, { PLUGIN_SETTING_P_A: "" }).values.get("p")?.["a"], "fallback");
+  const required = [pluginWith("p", [{ key: "a", required: true, type: "string" }])];
+  assert.match(resolveSettings(required, { PLUGIN_SETTING_P_A: "" }).errors.join("\n"), /must be set/);
+});
+
+test("a missing required setting is an error naming the plugin, the key and the variable", () => {
+  const result = resolveSettings([pluginWith("scheduling", [{ key: "timezone", required: true, type: "string" }])], {});
+  assert.equal(result.errors.length, 1);
+  assert.match(result.errors[0] ?? "", /scheduling/);
+  assert.match(result.errors[0] ?? "", /timezone/);
+  assert.match(result.errors[0] ?? "", /PLUGIN_SETTING_SCHEDULING_TIMEZONE/);
+});
+
+test("each type coerces from the environment, and a bad value fails loud", () => {
+  const decls: SettingDecl[] = [
+    { key: "text", type: "string" },
+    { key: "count", type: "number" },
+    { key: "flag", type: "boolean" },
+    { key: "mode", type: "enum", values: ["strict", "lenient"] },
+    { key: "base", type: "url" },
+  ];
+  const ok = resolveSettings([pluginWith("p", decls)], {
+    PLUGIN_SETTING_P_BASE: "https://example.com/v1",
+    PLUGIN_SETTING_P_COUNT: "42",
+    PLUGIN_SETTING_P_FLAG: "true",
+    PLUGIN_SETTING_P_MODE: "strict",
+    PLUGIN_SETTING_P_TEXT: "hello",
+  });
+  assert.deepEqual(ok.errors, []);
+  assert.deepEqual(ok.values.get("p"), { base: "https://example.com/v1", count: 42, flag: true, mode: "strict", text: "hello" });
+
+  const bad = resolveSettings([pluginWith("p", decls)], {
+    PLUGIN_SETTING_P_BASE: "not a url",
+    PLUGIN_SETTING_P_COUNT: "twelve",
+    PLUGIN_SETTING_P_FLAG: "yes",
+    PLUGIN_SETTING_P_MODE: "loose",
+  });
+  assert.equal(bad.errors.length, 4);
+  assert.match(bad.errors.join("\n"), /PLUGIN_SETTING_P_COUNT.*number/);
+  assert.match(bad.errors.join("\n"), /PLUGIN_SETTING_P_FLAG.*"true".*"false"/);
+  assert.match(bad.errors.join("\n"), /PLUGIN_SETTING_P_MODE.*strict, lenient/);
+  assert.match(bad.errors.join("\n"), /PLUGIN_SETTING_P_BASE.*URL/);
+});
+
+test("a boolean is only \"true\"/\"false\" — a typo never degrades to false", () => {
+  const plugins = [pluginWith("p", [{ default: true, key: "flag", type: "boolean" }])];
+  assert.equal(resolveSettings(plugins, { PLUGIN_SETTING_P_FLAG: "false" }).values.get("p")?.["flag"], false);
+  assert.equal(resolveSettings(plugins, { PLUGIN_SETTING_P_FLAG: "0" }).errors.length, 1);
+});
+
+test("REQUIRE_SECURE_SECRETS refuses an unset secret and one still on its dev default", () => {
+  const decls: SettingDecl[] = [{ default: "dev-insecure", key: "apiKey", secret: true, type: "string" }];
+  const plugins = [pluginWith("p", decls)];
+  assert.deepEqual(resolveSettings(plugins, {}).errors, []); // off: the dev default boots a clean clone
+
+  assert.match(resolveSettings(plugins, {}, { requireSecureSecrets: true }).errors.join("\n"), /apiKey.*must be set/);
+  assert.match(
+    resolveSettings(plugins, { PLUGIN_SETTING_P_API_KEY: "dev-insecure" }, { requireSecureSecrets: true }).errors.join("\n"),
+    /apiKey.*dev/,
+  );
+  assert.deepEqual(resolveSettings(plugins, { PLUGIN_SETTING_P_API_KEY: "real" }, { requireSecureSecrets: true }).errors, []);
+});
+
+test("a secret's value reaches the plugin but never the catalog", () => {
+  const plugins = [pluginWith("p", [{ key: "apiKey", secret: true, type: "string" }])];
+  const result = resolveSettings(plugins, { PLUGIN_SETTING_P_API_KEY: "s3cr3t" });
+  assert.equal(result.values.get("p")?.["apiKey"], "s3cr3t");
+
+  const entry = result.catalog[0]?.settings[0];
+  assert.equal(entry?.secret, true);
+  assert.equal(entry?.source, "env");
+  assert.equal(entry?.value, undefined); // not the value, not its length, not a mask of it
+  assert.ok(!JSON.stringify(result.catalog).includes("s3cr3t"));
+});
+
+test("the catalog carries every installed plugin, so \"declares none\" is not \"not installed\"", () => {
+  const plugins = [pluginWith("with", [{ default: "x", key: "a", type: "string" }]), { apiVersion: "0.2.0", id: "without" }];
+  const catalog = resolveSettings(plugins, {}).catalog;
+  assert.deepEqual(catalog.map((entry) => entry.pluginId), ["with", "without"]);
+  assert.deepEqual(catalog[1]?.settings, []);
+});
+
+test("a catalog entry carries the variable to set and where the value came from", () => {
+  const decls: SettingDecl[] = [
+    { description: "Where shifts come from", key: "upstream", required: true, type: "url" },
+    { default: 8, key: "maxHours", type: "number" },
+    { key: "note", type: "string" },
+  ];
+  const catalog = resolveSettings([pluginWith("scheduling", decls)], { PLUGIN_SETTING_SCHEDULING_UPSTREAM: "https://x.test" }).catalog;
+  assert.deepEqual(catalog[0]?.settings, [
+    { description: "Where shifts come from", envName: "PLUGIN_SETTING_SCHEDULING_UPSTREAM", key: "upstream", required: true, secret: false, source: "env", type: "url", value: "https://x.test" },
+    { envName: "PLUGIN_SETTING_SCHEDULING_MAX_HOURS", key: "maxHours", required: false, secret: false, source: "default", type: "number", value: "8" },
+    { envName: "PLUGIN_SETTING_SCHEDULING_NOTE", key: "note", required: false, secret: false, source: "unset", type: "string" },
+  ]);
+});
+
+test("a variable no plugin declares is reported, never acted on", () => {
+  const declared = settingsEnvNames([pluginWith("scheduling", [{ key: "timezone", type: "string" }])]);
+  const strays = strayNames(
+    { PATH: "/usr/bin", PLUGIN_DB_URL: "postgres://x", PLUGIN_SETTING_GONE_KEY: "x", PLUGIN_SETTING_SCHEDULING_TIMEZOME: "UTC", PLUGIN_SETTING_SCHEDULING_TIMEZONE: "UTC" },
+    declared,
+  );
+  assert.deepEqual(strays, ["PLUGIN_SETTING_GONE_KEY", "PLUGIN_SETTING_SCHEDULING_TIMEZOME"]); // sorted; the host's own untouched
+});
@@ -0,0 +1,259 @@
+// Per-plugin settings: the declaration shape, the env name it maps to, and the resolution rules
+// (README → Plugin settings). Pure — server.ts passes `process.env` in, so the whole matrix is
+// unit-testable without a stack.
+
+import type { Plugin } from "./plugin.ts";
+
+// `PLUGIN_` alone would let a plugin id "db" with key "url" produce the host's own PLUGIN_DB_URL.
+export const ENV_PREFIX = "PLUGIN_SETTING_";
+
+export const SETTING_TYPES = ["string", "number", "boolean", "enum", "url"] as const;
+export type SettingType = (typeof SETTING_TYPES)[number];
+
+export type SettingValue = boolean | number | string;
+
+// What a manifest declares. `required` and `default` are mutually exclusive: a default means the
+// setting can never fail resolution, which is the opposite of what required asserts.
+export interface SettingDecl {
+  default?: SettingValue;
+  description?: string;
+  key: string;
+  required?: boolean;
+  secret?: boolean; // value reaches the plugin, never a log, an error or the catalog
+  type: SettingType;
+  values?: readonly string[]; // enum only — the accepted choices
+}
+
+interface SettingTypeMap {
+  boolean: boolean;
+  enum: string;
+  number: number;
+  string: string;
+  url: string;
+}
+
+type ValueOfDecl<D> = D extends { type: "enum"; values: readonly (infer V extends string)[] }
+  ? V
+  : D extends { type: infer T extends keyof SettingTypeMap }
+    ? SettingTypeMap[T]
+    : never;
+
+// The resolved shape a plugin's onBoot receives, inferred from its own declarations so no caller
+// narrows with a cast. Only a required or defaulted setting is guaranteed present.
+export type SettingsOf<D extends readonly SettingDecl[]> = {
+  [K in D[number] as K["key"]]: K extends { required: true }
+    ? ValueOfDecl<K>
+    : K extends { default: SettingValue }
+      ? ValueOfDecl<K>
+      : ValueOfDecl<K> | undefined;
+};
+
+export type SettingsValues = Record<string, SettingValue | undefined>;
+
+// One row of the admin catalog. `value` is a display string and is absent for a secret and for an
+// unset setting — a secret's length is a disclosure too, so nothing stands in for it.
+export interface SettingSummary {
+  description?: string;
+  envName: string;
+  key: string;
+  required: boolean;
+  secret: boolean;
+  source: "default" | "env" | "unset";
+  type: SettingType;
+  value?: string;
+  values?: readonly string[];
+}
+
+export interface PluginSettings {
+  pluginId: string;
+  settings: SettingSummary[];
+}
+
+export interface ResolveResult {
+  catalog: PluginSettings[];
+  errors: string[];
+  values: Map<string, SettingsValues>;
+}
+
+export interface ResolveOptions {
+  requireSecureSecrets?: boolean;
+}
+
+type Env = Record<string, string | undefined>;
+
+const SETTING_KEY = /^[a-z][a-zA-Z0-9]*$/;
+
+export function isValidSettingKey(key: unknown): boolean {
+  return typeof key === "string" && SETTING_KEY.test(key);
+}
+
+export function envName(pluginId: string, key: string): string {
+  const plugin = pluginId.replaceAll("-", "_").toUpperCase();
+  return `${ENV_PREFIX}${plugin}_${camelToSnake(key)}`;
+}
+
+function camelToSnake(key: string): string {
+  return key.replaceAll(/(?<=[a-z0-9])(?=[A-Z])/g, "_").toUpperCase();
+}
+
+// Discovery-time shape check: the author's mistakes, refused before any value is read.
+export function settingsDeclError(settings: unknown): string | null {
+  if (!Array.isArray(settings)) return `"settings" must be an array`;
+
+  const seen = new Set<string>();
+  for (const decl of settings as SettingDecl[]) {
+    const key = decl?.key;
+    if (!isValidSettingKey(key)) {
+      return `setting "${String(key)}" — a key must be camelCase (${SETTING_KEY.source}) so its variable name is derivable`;
+    }
+    if (seen.has(key)) return `setting "${key}" is declared twice`;
+    seen.add(key);
+
+    if (!(SETTING_TYPES as readonly string[]).includes(decl.type)) {
+      return `setting "${key}" has type "${String(decl.type)}"; one of ${SETTING_TYPES.join(", ")}`;
+    }
+    if (decl.required === true && decl.default !== undefined) {
+      return `setting "${key}" sets both required and default — they are mutually exclusive, a default means it can never fail`;
+    }
+    if (decl.type === "enum") {
+      if (!Array.isArray(decl.values) || decl.values.length === 0 || decl.values.some((v) => typeof v !== "string")) {
+        return `setting "${key}" has type enum, so it must declare a non-empty values array of strings`;
+      }
+    } else if (decl.values !== undefined) {
+      return `setting "${key}" declares values, which only an enum type may do`;
+    }
+
+    const typeError = defaultTypeError(decl);
+    if (typeError) return typeError;
+  }
+  return null;
+}
+
+function defaultTypeError(decl: SettingDecl): string | null {
+  if (decl.default === undefined) return null;
+  if (decl.type === "enum") {
+    const values = decl.values ?? [];
+    return values.includes(String(decl.default))
+      ? null
+      : `setting "${decl.key}" has default "${String(decl.default)}", which is not one of ${values.join(", ")}`;
+  }
+  const expected = decl.type === "number" ? "number" : decl.type === "boolean" ? "boolean" : "string";
+  return typeof decl.default === expected
+    ? null
+    : `setting "${decl.key}": default must be a ${expected} (type ${decl.type}), got ${typeof decl.default}`;
+}
+
+// Every variable the installed plugins answer to — the set a stray is measured against.
+export function settingsEnvNames(plugins: Plugin[]): Set<string> {
+  const names = new Set<string>();
+  for (const plugin of plugins) {
+    for (const decl of plugin.settings ?? []) names.add(envName(plugin.id, decl.key));
+  }
+  return names;
+}
+
+// A PLUGIN_SETTING_ variable no installed plugin declares — usually a typo in the one the operator
+// meant to set, or a plugin they removed. Reported, never acted on (the orphan-database precedent).
+export function strayNames(env: Env, declared: ReadonlySet<string>): string[] {
+  return Object.keys(env)
+    .filter((name) => name.startsWith(ENV_PREFIX) && !declared.has(name))
+    .sort();
+}
+
+export function resolveSettings(plugins: Plugin[], env: Env, options: ResolveOptions = {}): ResolveResult {
+  const catalog: PluginSettings[] = [];
+  const errors: string[] = [];
+  const values = new Map<string, SettingsValues>();
+
+  for (const plugin of plugins) {
+    const decls = plugin.settings ?? [];
+    const resolved: SettingsValues = {};
+    const summaries: SettingSummary[] = [];
+
+    for (const decl of decls) {
+      const name = envName(plugin.id, decl.key);
+      const raw = env[name] || undefined; // compose passes an unset variable through as ""
+      const fail = (message: string): void => void errors.push(`plugin "${plugin.id}": ${message}`);
+
+      let value: SettingValue | undefined;
+      let source: SettingSummary["source"] = "unset";
+      if (raw !== undefined) {
+        const coerced = coerce(decl, raw, name);
+        if (typeof coerced === "string") fail(coerced);
+        else {
+          value = coerced.value;
+          source = "env";
+        }
+      } else if (decl.default !== undefined) {
+        value = decl.default;
+        source = "default";
+      } else if (decl.required === true) {
+        fail(`setting "${decl.key}" must be set — ${name} (type ${decl.type}, no default)`);
+      }
+
+      const secretError = secretPolicyError(decl, raw, options.requireSecureSecrets === true, name);
+      if (secretError) fail(secretError);
+
+      resolved[decl.key] = value;
+      summaries.push(summarize(decl, name, source, value));
+    }
+
+    if (decls.length > 0) values.set(plugin.id, resolved);
+    catalog.push({ pluginId: plugin.id, settings: summaries });
+  }
+
+  return { catalog, errors, values };
+}
+
+// The host's own rule for a secret (readSecret), reaching plugins: enforced, neither unset nor the
+// declared dev throwaway is accepted.
+function secretPolicyError(decl: SettingDecl, raw: string | undefined, enforce: boolean, name: string): string | null {
+  if (!enforce || decl.secret !== true) return null;
+  if (raw === undefined) return `setting "${decl.key}" must be set when REQUIRE_SECURE_SECRETS=true — ${name}`;
+  if (decl.default !== undefined && raw === String(decl.default)) {
+    return `setting "${decl.key}" must not be its dev default when REQUIRE_SECURE_SECRETS=true — ${name}`;
+  }
+  return null;
+}
+
+function summarize(decl: SettingDecl, name: string, source: SettingSummary["source"], value: SettingValue | undefined): SettingSummary {
+  const showValue = decl.secret !== true && value !== undefined;
+  return {
+    ...(decl.description !== undefined ? { description: decl.description } : {}),
+    envName: name,
+    key: decl.key,
+    required: decl.required === true,
+    secret: decl.secret === true,
+    source,
+    type: decl.type,
+    ...(showValue ? { value: String(value) } : {}),
+    ...(decl.values !== undefined ? { values: decl.values } : {}),
+  };
+}
+
+// A coerced value, or the boot error naming the variable and what it accepts.
+function coerce(decl: SettingDecl, raw: string, name: string): { value: SettingValue } | string {
+  switch (decl.type) {
+    case "boolean":
+      if (raw === "true") return { value: true };
+      if (raw === "false") return { value: false };
+      return `${name} must be "true" or "false", got "${raw}"`;
+    case "enum":
+      return (decl.values ?? []).includes(raw)
+        ? { value: raw }
+        : `${name} must be one of ${(decl.values ?? []).join(", ")}, got "${raw}"`;
+    case "number": {
+      const value = Number(raw);
+      return Number.isFinite(value) ? { value } : `${name} must be a number, got "${raw}"`;
+    }
+    case "url":
+      try {
+        new URL(raw);
+      } catch {
+        return `${name} is not a valid URL: ${raw}`;
+      }
+      return { value: raw };
+    case "string":
+      return { value: raw };
+  }
+}
@@ -14,6 +14,7 @@ import { createKratosAdmin } from "./auth/kratos-admin.ts";
 import { createKratosPublic } from "./auth/kratos-public.ts";
 import { createLogger, tracedFetch } from "./logger.ts";
 import { loadMenuConfig } from "./ui/menu-config.ts";
+import { resolveSettings, settingsEnvNames, strayNames } from "./plugin-host/settings.ts";
 import { buildCredentials, storagePluginIds, type StorageCredentials } from "./plugin-host/storage.ts";

 const config = loadConfig(); // validates the env (incl. enforced secrets) — fails loud at boot
@@ -62,15 +63,29 @@ const storageCredentials = new Map<string, StorageCredentials>();
 if (pluginDbUrl !== undefined) {
  for (const id of declaresStorage) storageCredentials.set(id, buildCredentials(pluginDbUrl, id, config.pluginDbSecret));
 }
-// onBoot is the only way credentials are handed over, so without one the database is provisioned
-// and unreachable. A warning, not a refusal — the plugin still works, it just cannot store anything.
-const unreachable = plugins.filter((plugin) => plugin.storage && !plugin.hooks?.onBoot).map((plugin) => plugin.id);
-if (unreachable.length > 0) log.warn("plugins declare storage but have no onBoot to receive it", { plugins: unreachable.join(", ") });
+// Operator-supplied plugin settings, resolved against the environment the manifests declared. A bad
+// or missing value is refused here rather than at that plugin's first use, hours later.
+const settings = resolveSettings(plugins, process.env, { requireSecureSecrets: config.requireSecureSecrets });
+if (settings.errors.length > 0) throw new Error(`Plugin settings:\n${settings.errors.map((e) => `  - ${e}`).join("\n")}`);
+// A stray is usually a typo in the very variable the operator meant to set — naming it turns two
+// unrelated-looking errors into one. Reported, never acted on.
+const strays = strayNames(process.env, settingsEnvNames(plugins));
+if (strays.length > 0) log.warn("settings variables no installed plugin declares", { variables: strays.join(", ") });
+
+// onBoot is the only way storage credentials and settings are handed over, so without one they are
+// resolved and undeliverable. A warning, not a refusal — the plugin still works, it just gets neither.
+for (const [what, ids] of [
+  ["settings", plugins.filter((plugin) => plugin.settings?.length && !plugin.hooks?.onBoot)],
+  ["storage", plugins.filter((plugin) => plugin.storage && !plugin.hooks?.onBoot)],
+] as const) {
+  if (ids.length > 0) log.warn(`plugins declare ${what} but have no onBoot to receive it`, { plugins: ids.map((plugin) => plugin.id).join(", ") });
+}

 // plugin onBoot — after discovery, before listen; a throw aborts boot.
 await runBootHooks(plugins, (plugin) => {
  const storage = storageCredentials.get(plugin.id);
-  return storage ? { storage } : {};
+  const values = settings.values.get(plugin.id);
+  return { ...(values ? { settings: values } : {}), ...(storage ? { storage } : {}) };
 });

 const server = createApp({
@@ -91,6 +106,7 @@ const server = createApp({
  menu,
  plugins,
  secureCookies: config.secureCookies,
+  settingsCatalog: settings.catalog,
 }).listen(config.port, () => {
  log.info("listening", { apiVersion: HOST_API_VERSION, port: config.port, url: config.appUrl ?? `http://localhost:${config.port}` });
 });
@@ -2,7 +2,6 @@

 ## Unfinnished work

- [ ] Add a way to configure plugins directly when installing. **Decided: the manifest declares it, not an `.env`** — a declared schema is validatable at boot, so a missing or mistyped setting fails loud and named the way a stray `package.json` now does, and the picker/docs can be generated from the declaration. Open: where the operator *supplies* the values (env var per key, a `config/` file, or both), and whether a secret may be declared at all.
 - [ ] Rename the plugin "admin" to something less generic, like "auth-admin" or "users-groups-admin".
 - [ ] Guard the group paths against self-lockout, or accept them explicitly. The self-revoke guard covers only your own *direct* grants on the Users screen; unticking a permission on a group you belong to, removing yourself from that group, or deleting it can all still strip your own effective access with no warning. Recorded in AGENTS.md as a known gap — the robust fix is a "last effective holder" check, which needs a reverse Keto query.
 - [ ] The permission picker has no concurrency baseline, so two operators editing the same user/group silently discard each other's change. Sketch: post the rendered set as a hidden baseline; if it no longer matches Keto, re-render with "this changed while you had the page open" rather than applying.
@@ -36,6 +35,7 @@ Prioritized. Overall verdict: architecture is sound; these are refinements.

 ## Finnished work

+- [x] Configure a plugin at install time: the manifest declares `settings`, the operator sets one `PLUGIN_SETTING_<ID>_<KEY>` variable per key, and the resolved values arrive on `onBoot` typed from the declaration. Read-only admin screen at `/admin/plugin-settings`.
 - [x] Give a plugin persistent storage: `storage: true` provisions a Postgres database + login role named `plugin_<id>`, credentials arrive on `onBoot`, passwords are derived from `PLUGIN_DB_SECRET` rather than stored.
 - [x] Refuse a stray `package.json`/`node_modules` in `config/` by name, as plugin folders already are.
 - [x] Let Renovate reach the example plugins' manifests (`ignorePaths` overrides `config:recommended`).
@@ -14,7 +14,7 @@
        <p>${t("dashboard.starter.intro")}</p>
        <p>${t("dashboard.starter.replace")}</p>
 <pre class="code-block"><code>export default definePlugin({
-  apiVersion: "0.1.0",
+  apiVersion: "0.2.0",
  // view names plugins/&lt;id&gt;/views/&lt;view&gt;.ejs, rendered in this same shell
  dashboard: (ctx) =&gt; ({ view: "dashboard", data: { /* … */ } }),
 });</code></pre>