diff --git a/README.md b/README.md
index e9cf2b3..5d17eec 100644
--- a/README.md
+++ b/README.md
@@ -88,6 +88,25 @@ on your IdP and threat model. Common, all valid, variants:
 The code treats `client_secret` as optional, so any of these is a config-only
 choice.
 
+#### Multiple IdPs
+
+`config.json` may instead list several providers, and the login screen shows one
+button per IdP ("Sign in with …"):
+
+```json
+{ "idps": [
+    { "id": "google", "label": "Google",   "issuer": "https://accounts.google.com", "client_id": "…" },
+    { "id": "acme",   "label": "Acme SSO", "issuer": "https://acme.auth0.com",      "client_id": "…", "client_secret": "…" }
+  ] }
+```
+
+Each entry takes the same fields as the single-IdP form (`issuer`, `client_id`,
+optional `client_secret`/`audience`/`bearer`/`ch_auth`/`authorize_params`) plus an
+optional `id`/`label` (default: the issuer host). A bare single object (above) is
+still accepted — it's treated as a one-IdP list. ClickHouse needs a matching
+`<token_processor>` per issuer; it validates each inbound JWT against whichever
+one matches the token's `iss`, so no extra CH wiring is required to offer several.
+
 ### Security headers
 
 `deploy/http_handlers.xml` sends a strict **Content-Security-Policy** plus
diff --git a/deploy/config.json.example b/deploy/config.json.example
index c4afb4c..55ce227 100644
--- a/deploy/config.json.example
+++ b/deploy/config.json.example
@@ -1,5 +1,10 @@
 {
-  "issuer": "https://accounts.google.com",
-  "client_id": "REPLACE_WITH_OAUTH_CLIENT_ID",
-  "audience": ""
+  "idps": [
+    {
+      "id": "google",
+      "label": "Google",
+      "issuer": "https://accounts.google.com",
+      "client_id": "REPLACE_WITH_OAUTH_CLIENT_ID"
+    }
+  ]
 }
diff --git a/src/net/oauth-config.js b/src/net/oauth-config.js
index f13d503..fd71532 100644
--- a/src/net/oauth-config.js
+++ b/src/net/oauth-config.js
@@ -1,55 +1,79 @@
-// Loads the deployment's OAuth configuration: `./config.json` (issuer +
-// client_id [+ optional client_secret/audience]) followed by the issuer's
-// OIDC discovery document to resolve the authorize/token endpoints.
+// Loads the deployment's OAuth configuration from `./config.json` — either a
+// single IdP (a bare object, legacy) or several (`{ idps: [...] }`).
+// `loadConfigDoc` fetches + normalizes the list; `resolveIdp` runs the issuer's
+// OIDC discovery for one chosen IdP into the object the oauth module consumes.
 //
-// `fetchFn` is injected so this is fully testable without a network. The
-// returned object is the canonical config the oauth module consumes.
+// `fetchFn` is injected so this is fully testable without a network.
+
+/** Host of an issuer URL, used as the default id/label. Falls back to the raw string. */
+function idpHost(issuer) {
+  try {
+    return new URL(issuer).host;
+  } catch {
+    return issuer;
+  }
+}
+
+/** Map one raw config.json entry to the canonical (pre-discovery) IdP descriptor. */
+function normalizeEntry(e) {
+  if (!e || !e.issuer || !e.client_id) {
+    throw new Error('config.json IdP missing issuer or client_id');
+  }
+  return {
+    id: e.id || idpHost(e.issuer),
+    label: e.label || idpHost(e.issuer),
+    issuer: e.issuer,
+    clientId: e.client_id,
+    clientSecret: e.client_secret || '',
+    audience: e.audience || '',
+    // Which token to send to ClickHouse: 'id_token' (default; forward-mode CH)
+    // or 'access_token' (audience-gated CH).
+    bearer: e.bearer === 'access_token' ? 'access_token' : 'id_token',
+    // How the token reaches ClickHouse: 'bearer' (default; Authorization: Bearer
+    // <jwt>) or 'basic' (Authorization: Basic base64(email:jwt), for OSS CH
+    // behind a verifier such as ch-jwt-verify).
+    chAuth: e.ch_auth === 'basic' ? 'basic' : 'bearer',
+    // Extra params merged into /authorize (e.g. Auth0 { organization: 'org_…' }).
+    authorizeParams: e.authorize_params && typeof e.authorize_params === 'object'
+      ? e.authorize_params
+      : {},
+  };
+}
 
 /**
+ * Fetch config.json and normalize to `{ idps: [descriptor, ...] }`. Accepts a
+ * list (`{ idps: [...] }`) or a single bare object (legacy) wrapped into one
+ * entry. Throws if no usable IdP is present.
  * @param {(url: string, init?: object) => Promise<Response>} fetchFn
  * @param {string} basePath  e.g. location.pathname ('/sql')
- * @returns {Promise<{clientId,clientSecret,audience,authUri,tokenUri,issuer}>}
  */
-export async function loadOAuthConfig(fetchFn, basePath = '') {
+export async function loadConfigDoc(fetchFn, basePath = '') {
   const cfgUrl = basePath.replace(/\/$/, '') + '/config.json';
   const cfgResp = await fetchFn(cfgUrl, { cache: 'no-store' });
   if (!cfgResp.ok) throw new Error('GET ' + cfgUrl + ': ' + cfgResp.status);
   const cfg = await cfgResp.json();
-  if (!cfg.issuer || !cfg.client_id) {
-    throw new Error('config.json missing issuer or client_id');
-  }
-  const discUrl = cfg.issuer.replace(/\/$/, '') + '/.well-known/openid-configuration';
+  const list = Array.isArray(cfg.idps) ? cfg.idps : [cfg];
+  if (!list.length) throw new Error('config.json has no IdPs');
+  return { idps: list.map(normalizeEntry) };
+}
+
+/**
+ * Resolve one IdP's authorize/token endpoints via OIDC discovery. Returns the
+ * descriptor extended with `authUri`/`tokenUri` — the object oauth.js consumes.
+ */
+export async function resolveIdp(fetchFn, idp) {
+  const discUrl = idp.issuer.replace(/\/$/, '') + '/.well-known/openid-configuration';
   const discResp = await fetchFn(discUrl, { cache: 'no-store' });
   if (!discResp.ok) throw new Error('OIDC discovery failed: ' + discResp.status);
   const disc = await discResp.json();
   if (!disc.authorization_endpoint || !disc.token_endpoint) {
     throw new Error('OIDC discovery missing authorization_endpoint or token_endpoint');
   }
-  return {
-    issuer: cfg.issuer,
-    clientId: cfg.client_id,
-    clientSecret: cfg.client_secret || '',
-    audience: cfg.audience || '',
-    authUri: disc.authorization_endpoint,
-    tokenUri: disc.token_endpoint,
-    // Which token to send to ClickHouse: 'id_token' (default; forward-mode CH
-    // that doesn't enforce audience) or 'access_token' (audience-gated CH).
-    bearer: cfg.bearer === 'access_token' ? 'access_token' : 'id_token',
-    // How the token reaches ClickHouse: 'bearer' (default; Authorization:
-    // Bearer <jwt>, for a CH token_processor) or 'basic' (Authorization: Basic
-    // base64(email:jwt), for OSS CH behind an http_authentication_servers
-    // verifier such as ch-jwt-verify where the JWT is the Basic password).
-    chAuth: cfg.ch_auth === 'basic' ? 'basic' : 'bearer',
-    // Extra params merged into the /authorize request (e.g. Auth0
-    // { "organization": "org_…" }). Pass-through, no interpretation.
-    authorizeParams: cfg.authorize_params && typeof cfg.authorize_params === 'object'
-      ? cfg.authorize_params
-      : {},
-  };
+  return { ...idp, authUri: disc.authorization_endpoint, tokenUri: disc.token_endpoint };
 }
 
 /**
- * Memoize a loader so config + discovery are fetched once. Returns a function
+ * Memoize a loader so the config document is fetched once. Returns a function
  * with the same signature; a failed load is not cached (so a retry re-fetches).
  */
 export function memoizeConfig(loader) {
diff --git a/src/styles.css b/src/styles.css
index c18a59d..721c83e 100644
--- a/src/styles.css
+++ b/src/styles.css
@@ -115,6 +115,7 @@ body {
   content: ''; width: 6px; height: 6px; border-radius: 4px;
   background: #22c55e; box-shadow: 0 0 6px #22c55e;
 }
+.login-actions { display: flex; flex-direction: column; gap: 8px; }
 .login-btn {
   width: 100%; height: 40px; padding: 0 16px;
   background: var(--accent); color: #fff;
diff --git a/src/ui/app.js b/src/ui/app.js
index d463b77..2bb2135 100644
--- a/src/ui/app.js
+++ b/src/ui/app.js
@@ -45,7 +45,22 @@ export function createApp(env = {}) {
     refreshToken: ss.getItem('oauth_refresh_token'),
   };
 
-  const loadConfig = oauthCfg.memoizeConfig(() => oauthCfg.loadOAuthConfig(fetchFn, loc.pathname));
+  // config.json may list several IdPs. Fetch the doc once; resolve OIDC
+  // discovery per selected IdP. The chosen IdP id is persisted so it survives
+  // the OAuth redirect (like oauth_state) and drives token exchange/refresh.
+  const loadDoc = oauthCfg.memoizeConfig(() => oauthCfg.loadConfigDoc(fetchFn, loc.pathname));
+  const resolvedCache = new Map();
+  app.idpId = ss.getItem('oauth_idp') || null;
+  function selectIdp(id) { app.idpId = id; ss.setItem('oauth_idp', id); }
+  async function resolveConfig() {
+    const { idps } = await loadDoc();
+    const chosen = idps.find((i) => i.id === app.idpId) || idps[0];
+    app.idpId = chosen.id;
+    if (!resolvedCache.has(chosen.id)) resolvedCache.set(chosen.id, oauthCfg.resolveIdp(fetchFn, chosen));
+    return resolvedCache.get(chosen.id);
+  }
+  app.loadIdps = loadDoc;
+  app.selectIdp = selectIdp;
 
   // --- persistence -------------------------------------------------------
   app.saveJSON = saveJSON;
@@ -75,18 +90,20 @@ export function createApp(env = {}) {
   function clearTokens() {
     app.token = null;
     app.refreshToken = null;
-    ['oauth_id_token', 'oauth_refresh_token', 'oauth_verifier', 'oauth_state'].forEach((k) => ss.removeItem(k));
+    app.idpId = null;
+    ['oauth_id_token', 'oauth_refresh_token', 'oauth_verifier', 'oauth_state', 'oauth_idp'].forEach((k) => ss.removeItem(k));
   }
   app.setTokens = setTokens;
   app.clearTokens = clearTokens;
-  app.loadConfig = loadConfig;
+  app.loadConfig = resolveConfig;
 
   app.signOut = () => { clearTokens(); renderLogin(app); };
   app.showLogin = (msg) => renderLogin(app, msg);
 
   // --- OAuth -------------------------------------------------------------
-  async function login() {
-    const cfg = await loadConfig();
+  async function login(idpId) {
+    if (idpId) selectIdp(idpId);
+    const cfg = await resolveConfig();
     const { verifier, challenge } = await generatePKCE(cryptoObj);
     const state = randomState(cryptoObj);
     ss.setItem('oauth_verifier', verifier);
@@ -99,7 +116,7 @@ export function createApp(env = {}) {
   }
 
   async function refresh() {
-    const cfg = await loadConfig();
+    const cfg = await resolveConfig();
     const tokens = await oauth.refreshTokens(fetchFn, cfg, app.refreshToken);
     const bearer = oauth.bearerFromTokens(tokens, cfg.bearer);
     if (!bearer) return false;
@@ -141,7 +158,7 @@ export function createApp(env = {}) {
   // rather than blocking the query.
   async function ensureConfig() {
     try {
-      const cfg = await loadConfig();
+      const cfg = await resolveConfig();
       app.chAuth = cfg.chAuth;
       return cfg;
     } catch {
@@ -348,7 +365,7 @@ export function createApp(env = {}) {
     selectTab: (id) => selectTab(app, id),
     closeTab: (id) => closeTab(app, id),
     loadIntoNewTab: (name, sql) => loadIntoNewTab(app, name, sql),
-    login,
+    login: (idpId) => login(idpId),
     share,
     toggleSaved: toggleSavedActive,
     formatQuery,
diff --git a/src/ui/login.js b/src/ui/login.js
index 2455850..ef668e4 100644
--- a/src/ui/login.js
+++ b/src/ui/login.js
@@ -1,15 +1,40 @@
-// The sign-in screen.
+// The sign-in screen. With several configured IdPs it shows one button per
+// provider; with a single IdP (or a legacy single-object config) it shows one
+// plain "Sign in" button.
 
 import { h } from './dom.js';
 
+// A sign-in button carrying the disable → "Redirecting…" → restore-on-error
+// flow. `idpId` is undefined for the single-IdP default (login() picks the only
+// one); otherwise it selects that provider.
+function signInButton(app, label, idpId) {
+  return h('button', {
+    class: 'login-btn',
+    onclick: async (e) => {
+      const btn = e.currentTarget;
+      btn.disabled = true;
+      btn.textContent = 'Redirecting…';
+      try {
+        await app.actions.login(idpId);
+      } catch (err) {
+        btn.disabled = false;
+        btn.textContent = label;
+        app.showLogin(String((err && err.message) || err));
+      }
+    },
+  }, label);
+}
+
 /**
  * Render the login screen into `root`. `app` provides:
- *   host()           — environment label
- *   actions.login()  — start the OAuth flow (async, may throw)
- *   showLogin(msg)   — re-render with an error message
+ *   host()             — environment label
+ *   actions.login(id?) — start the OAuth flow for IdP `id` (async, may throw)
+ *   loadIdps()         — resolve the configured IdP list (async)
+ *   showLogin(msg)     — re-render with an error message
  */
 export function renderLogin(app, errorMsg) {
   const root = app.root;
+  const actions = h('div', { class: 'login-actions' }, signInButton(app, 'Sign in'));
   root.replaceChildren(
     h('div', { class: 'login-screen' },
       h('div', { class: 'login-card' },
@@ -17,24 +42,20 @@ export function renderLogin(app, errorMsg) {
         h('div', { class: 'login-title' }, 'Altinity SQL Browser'),
         h('div', { class: 'login-sub' }, 'Sign in to continue'),
         h('div', { class: 'login-env' }, app.host()),
-        h('button', {
-          class: 'login-btn',
-          onclick: async (e) => {
-            const btn = e.currentTarget;
-            btn.disabled = true;
-            btn.textContent = 'Redirecting…';
-            try {
-              await app.actions.login();
-            } catch (err) {
-              btn.disabled = false;
-              btn.textContent = 'Sign in';
-              app.showLogin(String((err && err.message) || err));
-            }
-          },
-        }, 'Sign in'),
+        actions,
         errorMsg ? h('div', { class: 'login-error' }, errorMsg) : null,
         h('div', { class: 'login-foot' }, 'OAuth · OIDC discovery'),
       ),
     ),
   );
+  // With multiple IdPs, swap the single button for one button per provider.
+  if (app.loadIdps) {
+    app.loadIdps().then(({ idps }) => {
+      if (idps && idps.length > 1) {
+        actions.replaceChildren(
+          ...idps.map((idp) => signInButton(app, 'Sign in with ' + idp.label, idp.id)),
+        );
+      }
+    }).catch(() => { /* keep the single button; a click surfaces the config error */ });
+  }
 }
diff --git a/tests/unit/app.test.js b/tests/unit/app.test.js
index d13214a..5090f76 100644
--- a/tests/unit/app.test.js
+++ b/tests/unit/app.test.js
@@ -323,6 +323,29 @@ describe('auth flows', () => {
     expect(e.sessionStorage.getItem('oauth_verifier')).toBeTruthy();
     expect(e.sessionStorage.getItem('oauth_state')).toBeTruthy();
   });
+  it('multi-IdP: login(id) selects that IdP, persists it, and uses its endpoints', async () => {
+    const loc = { host: 'ch', origin: 'https://ch', pathname: '/sql', search: '', hash: '', href: 'https://ch/sql' };
+    const e = env({
+      location: loc,
+      sessionStorage: memSession({}),
+      fetch: makeFetch([
+        [(u) => /config\.json/.test(u), resp({ json: { idps: [
+          { id: 'google', issuer: 'https://accounts.google.com', client_id: 'g' },
+          { id: 'auth0', issuer: 'https://acme.auth0.com', client_id: 'a' },
+        ] } })],
+        [(u) => /acme\.auth0\.com\/.well-known/.test(u), resp({ json: { authorization_endpoint: 'https://acme.auth0.com/authorize', token_endpoint: 'https://acme.auth0.com/t' } })],
+        [(u) => /accounts\.google\.com\/.well-known/.test(u), resp({ json: { authorization_endpoint: 'https://accounts.google.com/auth', token_endpoint: 'https://t' } })],
+      ]),
+    });
+    const app = createApp(e);
+    expect((await app.loadIdps()).idps).toHaveLength(2);
+    await app.actions.login('auth0');
+    expect(loc.href).toContain('https://acme.auth0.com/authorize?');
+    expect(loc.href).toContain('client_id=a');
+    expect(e.sessionStorage.getItem('oauth_idp')).toBe('auth0');
+    app.signOut();
+    expect(e.sessionStorage.getItem('oauth_idp')).toBeNull(); // cleared on sign-out
+  });
   it('refresh succeeds via the ClickHouse context', async () => {
     const e = env({
       sessionStorage: memSession({ oauth_id_token: jwt({ exp: 1 }), oauth_refresh_token: 'rt' }),
diff --git a/tests/unit/login.test.js b/tests/unit/login.test.js
index ae5d713..0e1c48c 100644
--- a/tests/unit/login.test.js
+++ b/tests/unit/login.test.js
@@ -48,4 +48,33 @@ describe('renderLogin', () => {
     await tick();
     expect(showLogin).toHaveBeenCalledWith('rawstr');
   });
+
+  it('multiple IdPs → one button per provider, clicking passes the IdP id', async () => {
+    const login = vi.fn(async () => {});
+    const app = makeApp({
+      actions: { ...makeApp().actions, login },
+      loadIdps: async () => ({ idps: [{ id: 'g', label: 'Google' }, { id: 'a', label: 'Acme SSO' }] }),
+    });
+    renderLogin(app);
+    await tick();
+    const btns = [...app.root.querySelectorAll('.login-btn')];
+    expect(btns.map((b) => b.textContent)).toEqual(['Sign in with Google', 'Sign in with Acme SSO']);
+    btns[1].dispatchEvent(new Event('click'));
+    await tick();
+    expect(login).toHaveBeenCalledWith('a');
+  });
+  it('a single IdP keeps the lone Sign in button', async () => {
+    const app = makeApp({ loadIdps: async () => ({ idps: [{ id: 'g', label: 'Google' }] }) });
+    renderLogin(app);
+    await tick();
+    const btns = [...app.root.querySelectorAll('.login-btn')];
+    expect(btns).toHaveLength(1);
+    expect(btns[0].textContent).toBe('Sign in');
+  });
+  it('keeps the single button when the IdP list fails to load', async () => {
+    const app = makeApp({ loadIdps: async () => { throw new Error('no config'); } });
+    renderLogin(app);
+    await tick();
+    expect(app.root.querySelectorAll('.login-btn')).toHaveLength(1);
+  });
 });
diff --git a/tests/unit/oauth-config.test.js b/tests/unit/oauth-config.test.js
index 97f549b..7661dfe 100644
--- a/tests/unit/oauth-config.test.js
+++ b/tests/unit/oauth-config.test.js
@@ -1,5 +1,5 @@
 import { describe, it, expect, vi } from 'vitest';
-import { loadOAuthConfig, memoizeConfig } from '../../src/net/oauth-config.js';
+import { loadConfigDoc, resolveIdp, memoizeConfig } from '../../src/net/oauth-config.js';
 
 const resp = (ok, body, status = ok ? 200 : 500) => ({
   ok,
@@ -14,94 +14,95 @@ function fetcher(map) {
   });
 }
 
-const okConfig = { issuer: 'https://accounts.google.com', client_id: 'cid', client_secret: 'sek', audience: 'aud' };
 const okDisc = {
   authorization_endpoint: 'https://accounts.google.com/o/oauth2/v2/auth',
   token_endpoint: 'https://oauth2.googleapis.com/token',
 };
 
-describe('loadOAuthConfig', () => {
-  it('resolves config + discovery', async () => {
-    const f = fetcher([
-      [/config\.json$/, resp(true, okConfig)],
-      [/openid-configuration$/, resp(true, okDisc)],
-    ]);
-    const cfg = await loadOAuthConfig(f, '/sql');
-    expect(cfg).toEqual({
-      issuer: 'https://accounts.google.com',
-      clientId: 'cid',
-      clientSecret: 'sek',
-      audience: 'aud',
-      authUri: okDisc.authorization_endpoint,
-      tokenUri: okDisc.token_endpoint,
-      bearer: 'id_token',
-      chAuth: 'bearer',
-      authorizeParams: {},
-    });
+describe('loadConfigDoc', () => {
+  const docOf = async (body, base = '/sql') =>
+    (await loadConfigDoc(fetcher([[/config\.json$/, resp(true, body)]]), base)).idps;
+
+  it('wraps a single bare-object config into one IdP (host id/label defaults)', async () => {
+    const f = fetcher([[/config\.json$/, resp(true, {
+      issuer: 'https://accounts.google.com', client_id: 'cid', client_secret: 'sek', audience: 'aud',
+    })]]);
+    const { idps } = await loadConfigDoc(f, '/sql');
+    expect(idps).toEqual([{
+      id: 'accounts.google.com', label: 'accounts.google.com',
+      issuer: 'https://accounts.google.com', clientId: 'cid', clientSecret: 'sek',
+      audience: 'aud', bearer: 'id_token', chAuth: 'bearer', authorizeParams: {},
+    }]);
     expect(f.mock.calls[0][0]).toBe('/sql/config.json');
   });
-  it('defaults clientSecret/audience/bearer/authorizeParams', async () => {
-    const f = fetcher([
-      [/config\.json$/, resp(true, { issuer: 'https://i', client_id: 'c' })],
-      [/openid-configuration$/, resp(true, okDisc)],
+  it('parses a list and honours explicit id/label', async () => {
+    const idps = await docOf({ idps: [
+      { id: 'g', label: 'Google', issuer: 'https://accounts.google.com', client_id: 'c1' },
+      { id: 'a', label: 'Acme', issuer: 'https://acme.auth0.com', client_id: 'c2', bearer: 'access_token' },
+    ] });
+    expect(idps.map((i) => [i.id, i.label, i.bearer])).toEqual([
+      ['g', 'Google', 'id_token'], ['a', 'Acme', 'access_token'],
     ]);
-    const cfg = await loadOAuthConfig(f, '');
-    expect(cfg.clientSecret).toBe('');
-    expect(cfg.audience).toBe('');
-    expect(cfg.bearer).toBe('id_token');
-    expect(cfg.chAuth).toBe('bearer');
-    expect(cfg.authorizeParams).toEqual({});
   });
-  it('honours ch_auth=basic', async () => {
-    const f = fetcher([
-      [/config\.json$/, resp(true, { issuer: 'https://i', client_id: 'c', ch_auth: 'basic' })],
-      [/openid-configuration$/, resp(true, okDisc)],
-    ]);
-    const cfg = await loadOAuthConfig(f, '');
-    expect(cfg.chAuth).toBe('basic');
+  it('defaults id/label to the issuer host, and to the raw string for a non-URL issuer', async () => {
+    const idps = await docOf({ idps: [
+      { issuer: 'https://acme.auth0.com', client_id: 'c' },
+      { issuer: 'weird', client_id: 'c' },
+    ] });
+    expect(idps[0].id).toBe('acme.auth0.com');
+    expect(idps[1].id).toBe('weird'); // new URL('weird') throws → raw fallback
   });
-  it('honours bearer=access_token and authorize_params object', async () => {
-    const f = fetcher([
-      [/config\.json$/, resp(true, {
-        issuer: 'https://i', client_id: 'c', bearer: 'access_token',
-        authorize_params: { organization: 'org_x' },
-      })],
-      [/openid-configuration$/, resp(true, okDisc)],
-    ]);
-    const cfg = await loadOAuthConfig(f, '');
-    expect(cfg.bearer).toBe('access_token');
-    expect(cfg.authorizeParams).toEqual({ organization: 'org_x' });
+  it('defaults clientSecret/audience/bearer/chAuth/authorizeParams', async () => {
+    const [idp] = await docOf({ issuer: 'https://i', client_id: 'c' });
+    expect(idp.clientSecret).toBe('');
+    expect(idp.audience).toBe('');
+    expect(idp.bearer).toBe('id_token');
+    expect(idp.chAuth).toBe('bearer');
+    expect(idp.authorizeParams).toEqual({});
+  });
+  it('honours ch_auth=basic, bearer=access_token, and an authorize_params object', async () => {
+    const [idp] = await docOf({
+      issuer: 'https://i', client_id: 'c', ch_auth: 'basic', bearer: 'access_token',
+      authorize_params: { organization: 'org_x' },
+    });
+    expect(idp.chAuth).toBe('basic');
+    expect(idp.bearer).toBe('access_token');
+    expect(idp.authorizeParams).toEqual({ organization: 'org_x' });
   });
   it('ignores a non-object authorize_params and an unknown bearer', async () => {
-    const f = fetcher([
-      [/config\.json$/, resp(true, { issuer: 'https://i', client_id: 'c', bearer: 'weird', authorize_params: 'nope' })],
-      [/openid-configuration$/, resp(true, okDisc)],
-    ]);
-    const cfg = await loadOAuthConfig(f, '');
-    expect(cfg.bearer).toBe('id_token');
-    expect(cfg.authorizeParams).toEqual({});
+    const [idp] = await docOf({ issuer: 'https://i', client_id: 'c', bearer: 'weird', authorize_params: 'nope' });
+    expect(idp.bearer).toBe('id_token');
+    expect(idp.authorizeParams).toEqual({});
   });
   it('throws when config.json is not ok', async () => {
     const f = fetcher([[/config\.json$/, resp(false, null, 404)]]);
-    await expect(loadOAuthConfig(f, '/sql')).rejects.toThrow('config.json: 404');
+    await expect(loadConfigDoc(f, '/sql')).rejects.toThrow('config.json: 404');
+  });
+  it('throws when an IdP lacks issuer/client_id', async () => {
+    await expect(docOf({ issuer: 'x' })).rejects.toThrow('missing issuer or client_id');
   });
-  it('throws when config.json lacks issuer/client_id', async () => {
-    const f = fetcher([[/config\.json$/, resp(true, { issuer: 'x' })]]);
-    await expect(loadOAuthConfig(f, '/sql')).rejects.toThrow('missing issuer or client_id');
+  it('throws when the idps list is empty', async () => {
+    await expect(docOf({ idps: [] })).rejects.toThrow('no IdPs');
+  });
+});
+
+describe('resolveIdp', () => {
+  const idp = {
+    id: 'i', label: 'I', issuer: 'https://i', clientId: 'c', clientSecret: '',
+    audience: '', bearer: 'id_token', chAuth: 'bearer', authorizeParams: {},
+  };
+  it('adds authUri/tokenUri from OIDC discovery, preserving the descriptor', async () => {
+    const f = fetcher([[/openid-configuration$/, resp(true, okDisc)]]);
+    const cfg = await resolveIdp(f, idp);
+    expect(cfg).toEqual({ ...idp, authUri: okDisc.authorization_endpoint, tokenUri: okDisc.token_endpoint });
   });
   it('throws when discovery is not ok', async () => {
-    const f = fetcher([
-      [/config\.json$/, resp(true, okConfig)],
-      [/openid-configuration$/, resp(false, null, 500)],
-    ]);
-    await expect(loadOAuthConfig(f, '/sql')).rejects.toThrow('OIDC discovery failed: 500');
+    const f = fetcher([[/openid-configuration$/, resp(false, null, 500)]]);
+    await expect(resolveIdp(f, idp)).rejects.toThrow('OIDC discovery failed: 500');
   });
   it('throws when discovery lacks endpoints', async () => {
-    const f = fetcher([
-      [/config\.json$/, resp(true, okConfig)],
-      [/openid-configuration$/, resp(true, { authorization_endpoint: 'a' })],
-    ]);
-    await expect(loadOAuthConfig(f, '/sql')).rejects.toThrow('missing authorization_endpoint or token_endpoint');
+    const f = fetcher([[/openid-configuration$/, resp(true, { authorization_endpoint: 'a' })]]);
+    await expect(resolveIdp(f, idp)).rejects.toThrow('missing authorization_endpoint or token_endpoint');
   });
 });