diff --git a/ads/yieldmo.js b/ads/yieldmo.js
index 5a410cc350f9..9e4161298fba 100644
--- a/ads/yieldmo.js
+++ b/ads/yieldmo.js
@@ -25,7 +25,7 @@ export function yieldmo(global, data) {
   const ymElem = global.document.createElement('div');
   ymElem.id = 'ym_' + data.ymid;
   ymElem.className = 'ym';
-  ymElem.dataset.ampEnabled = true;
+  ymElem.dataset['ampEnabled'] = true;
   global.document.getElementById('c').appendChild(ymElem);
 
   const ymJs = 'https://static.yieldmo.com/ym.amp1.js';
diff --git a/build-system/amp.extern.js b/build-system/amp.extern.js
index 34bf09fe71f1..f493d6430efc 100644
--- a/build-system/amp.extern.js
+++ b/build-system/amp.extern.js
@@ -26,6 +26,12 @@
  */
 function JsonObject() {}
 
+/**
+ * Force the dataset property to be handled as a JsonObject.
+ * @type {!JsonObject}
+ */
+Element.prototype.dataset;
+
 /**
  * - n is the name.
  * - f is the function body of the extension.
diff --git a/build-system/tasks/compile.js b/build-system/tasks/compile.js
index 7787dd2db07d..349fa8c4189e 100644
--- a/build-system/tasks/compile.js
+++ b/build-system/tasks/compile.js
@@ -154,6 +154,8 @@ function compile(entryModuleFilenames, outputDir,
       'extensions/amp-bind/**/*.js',
       // Needed to access form impl from other extensions
       'extensions/amp-form/**/*.js',
+      // Needed for AccessService
+      'extensions/amp-access/**/*.js',
       // Needed to access UserNotificationManager from other extensions
       'extensions/amp-user-notification/**/*.js',
       'src/*.js',
@@ -283,6 +285,8 @@ function compile(entryModuleFilenames, outputDir,
           'build/patched-module/',
           // Can't seem to suppress `(0, win.eval)` suspicious code warning
           '3p/environment.js',
+          // Generated code.
+          'extensions/amp-access/0.1/access-expr-impl.js',
         ],
         jscomp_error: [],
       }
diff --git a/extensions/amp-access-laterpay/0.1/laterpay-impl.js b/extensions/amp-access-laterpay/0.1/laterpay-impl.js
index f8eb15ecbfdb..96e075f19e8d 100644
--- a/extensions/amp-access-laterpay/0.1/laterpay-impl.js
+++ b/extensions/amp-access-laterpay/0.1/laterpay-impl.js
@@ -19,6 +19,7 @@ import {dev, user} from '../../../src/log';
 import {installStyles} from '../../../src/style-installer';
 import {installStylesForShadowRoot} from '../../../src/shadow-embed';
 import {getMode} from '../../../src/mode';
+import {dict} from '../../../src/utils/object';
 import {listen} from '../../../src/event-helper';
 import {removeChildren} from '../../../src/dom';
 import {timerFor} from '../../../src/services';
@@ -46,13 +47,13 @@ const DEFAULT_MESSAGES = {
 
 /**
  * @typedef {{
- *   articleTitleSelector: !string,
- *   configUrl: string=,
- *   articleId: string=,
- *   scrollToTopAfterAuth: boolean=,
- *   locale: string=,
- *   localeMessages: object=,
- *   sandbox: boolean=,
+ *   articleTitleSelector: string,
+ *   configUrl: (string|undefined),
+ *   articleId: (string|undefined),
+ *   scrollToTopAfterAuth: (boolean|undefined),
+ *   locale: (string|undefined),
+ *   localeMessages: (Object|undefined),
+ *   sandbox: (boolean|undefined),
  * }}
  */
 let LaterpayConfigDef;
@@ -76,35 +77,35 @@ let PurchaseOptionDef;
  *   access: boolean,
  *   apl: string,
  *   premiumcontent: !PurchaseOptionDef,
- *   timepasses: Array<PurchaseOptionDef>=,
- *   subscriptions: Array<PurchaseOptionDef>=
+ *   timepasses: (!Array<PurchaseOptionDef>|undefined),
+ *   subscriptions: (!Array<PurchaseOptionDef>|undefined)
  * }}
  */
 let PurchaseConfigDef;
 
 
 /**
- * @implements {AccessVendor}
+ * @implements {../../amp-access/0.1/access-vendor.AccessVendor}
  */
 export class LaterpayVendor {
 
   /**
-   * @param {!AccessService} accessService
+   * @param {!../../amp-access/0.1/amp-access.AccessService} accessService
    */
   constructor(accessService) {
     /** @const */
     this.ampdoc = accessService.ampdoc;
 
-    /** @const @private {!AccessService} */
+    /** @const @private {!../../amp-access/0.1/amp-access.AccessService} */
     this.accessService_ = accessService;
 
-    /** @private @const {!Viewport} */
+    /** @private @const {!../../../src/service/viewport-impl.Viewport} */
     this.viewport_ = viewportForDoc(this.ampdoc);
 
-    /** @const @private {!LaterpayConfigDef} */
+    /** @const @private {!JsonObject} For shape see LaterpayConfigDef */
     this.laterpayConfig_ = this.accessService_.getAdapterConfig();
 
-    /** @private {?PurchaseConfigDef} */
+    /** @private {?JsonObject} For shape see PurchaseConfigDef */
     this.purchaseConfig_ = null;
 
     /** @private {?Function} */
@@ -113,7 +114,7 @@ export class LaterpayVendor {
     /** @private {?Function} */
     this.alreadyPurchasedListener_ = null;
 
-    /** @const @private {!Array<function(!Event)>} */
+    /** @const @private {!Array<function()>} */
     this.purchaseOptionListeners_ = [];
 
     /** @private {!boolean} */
@@ -129,27 +130,27 @@ export class LaterpayVendor {
     this.purchaseButton_ = null;
 
     /** @private {string} */
-    this.currentLocale_ = this.laterpayConfig_.locale || 'en';
+    this.currentLocale_ = this.laterpayConfig_['locale'] || 'en';
 
-    /** @private {Object} */
-    this.i18n_ = Object.assign({}, DEFAULT_MESSAGES,
-        this.laterpayConfig_.localeMessages || {});
+    /** @private {!JsonObject} */
+    this.i18n_ = /** @type {!JsonObject} */ (Object.assign(dict(),
+        DEFAULT_MESSAGES, this.laterpayConfig_['localeMessages'] || dict()));
 
     /** @private {string} */
     this.purchaseConfigBaseUrl_ = this.getConfigUrl_() + CONFIG_BASE_PATH;
-    const articleId = this.laterpayConfig_.articleId;
+    const articleId = this.laterpayConfig_['articleId'];
     if (articleId) {
       this.purchaseConfigBaseUrl_ +=
         '&article_id=' + encodeURIComponent(articleId);
     }
 
-    /** @const @private {!Timer} */
+    /** @const @private {!../../../src/service/timer-impl.Timer} */
     this.timer_ = timerFor(this.ampdoc.win);
 
-    /** @const @private {!Vsync} */
+    /** @const @private {!../../../src/service/vsync-impl.Vsync} */
     this.vsync_ = vsyncFor(this.ampdoc.win);
 
-    /** @const @private {!Xhr} */
+    /** @const @private {!../../../src/service/xhr-impl.Xhr} */
     this.xhr_ = xhrFor(this.ampdoc.win);
 
     // Install styles.
@@ -169,10 +170,10 @@ export class LaterpayVendor {
   getConfigUrl_() {
     if (
       (getMode().localDev || getMode().development) &&
-      this.laterpayConfig_.configUrl
+      this.laterpayConfig_['configUrl']
     ) {
-      return this.laterpayConfig_.configUrl;
-    } else if (this.laterpayConfig_.sandbox) {
+      return this.laterpayConfig_['configUrl'];
+    } else if (this.laterpayConfig_['sandbox']) {
       return SANDBOX_CONFIG_URL;
     } else {
       return CONFIG_URL;
@@ -191,7 +192,7 @@ export class LaterpayVendor {
             'article, or no paid content configurations are setup.');
           }
 
-          if (this.laterpayConfig_.scrollToTopAfterAuth) {
+          if (this.laterpayConfig_['scrollToTopAfterAuth']) {
             this.vsync_.mutate(() => this.viewport_.setScrollTop(0));
           }
           this.emptyContainer_();
@@ -250,23 +251,23 @@ export class LaterpayVendor {
    */
   getArticleTitle_() {
     const title = this.ampdoc.getRootNode().querySelector(
-        this.laterpayConfig_.articleTitleSelector);
+        this.laterpayConfig_['articleTitleSelector']);
     user().assert(
         title, 'No article title element found with selector %s',
-        this.laterpayConfig_.articleTitleSelector);
+        this.laterpayConfig_['articleTitleSelector']);
     return title.textContent.trim();
   }
 
   /**
-   * @return {!Node}
+   * @return {!Element}
    * @private
    */
   getContainer_() {
     const id = TAG + '-dialog';
     const dialogContainer = this.ampdoc.getElementById(id);
-    return user().assert(
+    return user().assertElement(
         dialogContainer,
-        'No element found with id %s', id
+        'No element found with id ' + id
     );
   }
 
@@ -305,46 +306,48 @@ export class LaterpayVendor {
     const dialogContainer = this.getContainer_();
     this.innerContainer_ = this.createElement_('div');
     this.innerContainer_.className = TAG + '-container';
-    if (this.laterpayConfig_.sandbox) {
+    if (this.laterpayConfig_['sandbox']) {
       this.renderTextBlock_('sandbox');
     }
     this.renderTextBlock_('header');
     const listContainer = this.createElement_('ul');
-    this.purchaseConfig_.premiumcontent['tp_title'] =
-      this.i18n_.premiumContentTitle;
-    this.purchaseConfig_.premiumcontent.description = this.getArticleTitle_();
+    this.purchaseConfig_['premiumcontent']['tp_title'] =
+      this.i18n_['premiumContentTitle'];
+    this.purchaseConfig_['premiumcontent']['description'] =
+        this.getArticleTitle_();
     listContainer.appendChild(
-        this.createPurchaseOption_(this.purchaseConfig_.premiumcontent)
+        this.createPurchaseOption_(this.purchaseConfig_['premiumcontent'])
     );
-    this.purchaseConfig_.timepasses.forEach(timepass => {
+    this.purchaseConfig_['timepasses'].forEach(timepass => {
       listContainer.appendChild(this.createPurchaseOption_(timepass));
     });
-    this.purchaseConfig_.subscriptions.forEach(subscription => {
+    this.purchaseConfig_['subscriptions'].forEach(subscription => {
       listContainer.appendChild(this.createPurchaseOption_(subscription));
     });
     const purchaseButton = this.createElement_('button');
     purchaseButton.className = TAG + '-purchase-button';
-    purchaseButton.textContent = this.i18n_.defaultButton;
+    purchaseButton.textContent = this.i18n_['defaultButton'];
     this.purchaseButton_ = purchaseButton;
     this.purchaseButtonListener_ = listen(purchaseButton, 'click', ev => {
       const value = this.selectedPurchaseOption_.value;
-      const purchaseType = this.selectedPurchaseOption_.dataset.purchaseType;
+      const purchaseType = this.selectedPurchaseOption_.dataset['purchaseType'];
       this.handlePurchase_(ev, value, purchaseType);
     });
     this.innerContainer_.appendChild(listContainer);
     this.innerContainer_.appendChild(purchaseButton);
     this.innerContainer_.appendChild(
-        this.createAlreadyPurchasedLink_(this.purchaseConfig_.apl));
+        this.createAlreadyPurchasedLink_(this.purchaseConfig_['apl']));
     this.renderTextBlock_('footer');
     dialogContainer.appendChild(this.innerContainer_);
     dialogContainer.appendChild(this.createLaterpayBadge_());
     this.containerEmpty_ = false;
-    this.preselectFirstOption_(listContainer.firstElementChild);
+    this.preselectFirstOption_(
+        dev().assertElement(listContainer.firstElementChild));
   }
 
   /**
    * @private
-   * @param {!Node} firstOption
+   * @param {!Element} firstOption
    */
   preselectFirstOption_(firstOption) {
     const firstInput = firstOption.querySelector('input[type="radio"]');
@@ -367,7 +370,7 @@ export class LaterpayVendor {
 
   /**
    * @private
-   * @return {!Node}
+   * @return {!Element}
    */
   createLaterpayBadge_() {
     const a = this.createElement_('a');
@@ -382,42 +385,42 @@ export class LaterpayVendor {
   }
 
   /**
-   * @param {!PurchaseOptionDef} option
-   * @return {!Node}
+   * @param {!JsonObject} option Shape: PurchaseOptionDef
+   * @return {!Element}
    * @private
    */
   createPurchaseOption_(option) {
     const li = this.createElement_('li');
     const control = this.createElement_('label');
-    control.for = option.tp_title;
+    control.for = option['tp_title'];
     control.appendChild(this.createRadioControl_(option));
     const metadataContainer = this.createElement_('div');
     metadataContainer.className = TAG + '-metadata';
     const title = this.createElement_('span');
     title.className = TAG + '-title';
-    title.textContent = option.tp_title;
+    title.textContent = option['tp_title'];
     metadataContainer.appendChild(title);
     const description = this.createElement_('p');
     description.className = TAG + '-description';
-    description.textContent = option.description;
+    description.textContent = option['description'];
     metadataContainer.appendChild(description);
     control.appendChild(metadataContainer);
     li.appendChild(control);
-    li.appendChild(this.createPrice_(option.price));
+    li.appendChild(this.createPrice_(option['price']));
     return li;
   }
 
   /**
-   * @param {!PurchaseOptionDef} option
-   * @return {!Node}
+   * @param {!JsonObject} option Shape: PurchaseOptionDef
+   * @return {!Element}
    * @private
    */
   createRadioControl_(option) {
     const radio = this.createElement_('input');
     radio.name = 'purchaseOption';
     radio.type = 'radio';
-    radio.id = option.tp_title;
-    radio.value = option.purchase_url;
+    radio.id = option['tp_title'];
+    radio.value = option['purchase_url'];
     const purchaseType = option['purchase_type'] === 'ppu' ?
       'payLater' :
       'payNow';
@@ -432,7 +435,7 @@ export class LaterpayVendor {
 
   /**
    * @param {!Object<string, number>} price
-   * @return {!Node}
+   * @return {!Element}
    * @private
    */
   createPrice_(price) {
@@ -467,14 +470,14 @@ export class LaterpayVendor {
 
   /**
    * @param {!string} href
-   * @return {!Node}
+   * @return {!Element}
   */
   createAlreadyPurchasedLink_(href) {
     const p = this.createElement_('p');
     p.className = TAG + '-already-purchased-link-container';
     const a = this.createElement_('a');
     a.href = href;
-    a.textContent = this.i18n_.alreadyPurchasedLink;
+    a.textContent = this.i18n_['alreadyPurchasedLink'];
     this.alreadyPurchasedListener_ = listen(a, 'click', ev => {
       this.handlePurchase_(ev, href, 'alreadyPurchased');
     });
@@ -488,17 +491,17 @@ export class LaterpayVendor {
    */
   handlePurchaseOptionSelection_(ev) {
     ev.preventDefault();
-    this.selectPurchaseOption_(ev.target);
+    this.selectPurchaseOption_(dev().assertElement(ev.target));
   }
 
   /**
-   * @param {!Node} target
+   * @param {!Element} target
    * @private
    */
   selectPurchaseOption_(target) {
     const selectedOptionClassname = TAG + '-selected';
     const prevPurchaseOption = this.selectedPurchaseOption_;
-    const purchaseActionLabel = target.dataset.purchaseActionLabel;
+    const purchaseActionLabel = target.dataset['purchaseActionLabel'];
     if (prevPurchaseOption &&
         prevPurchaseOption.classList.contains(selectedOptionClassname)) {
       prevPurchaseOption.classList.remove(selectedOptionClassname);
diff --git a/extensions/amp-access/0.1/amp-access-client.js b/extensions/amp-access/0.1/amp-access-client.js
index cd8038df9407..e50bb6fe5b34 100644
--- a/extensions/amp-access/0.1/amp-access-client.js
+++ b/extensions/amp-access/0.1/amp-access-client.js
@@ -27,19 +27,19 @@ const TAG = 'amp-access-client';
 const DEFAULT_AUTHORIZATION_TIMEOUT = 3000;
 
 
-/** @implements {AccessTypeAdapterDef} */
+/** @implements {./amp-access.AccessTypeAdapterDef} */
 export class AccessClientAdapter {
 
   /**
    * @param {!../../../src/service/ampdoc-impl.AmpDoc} ampdoc
    * @param {!JsonObject} configJson
-   * @param {!AccessTypeAdapterContextDef} context
+   * @param {!./amp-access.AccessTypeAdapterContextDef} context
    */
   constructor(ampdoc, configJson, context) {
     /** @const */
     this.ampdoc = ampdoc;
 
-    /** @const @private {!AccessTypeAdapterContextDef} */
+    /** @const @private {!./amp-access.AccessTypeAdapterContextDef} */
     this.context_ = context;
 
     /** @const @private {string} */
@@ -61,10 +61,10 @@ export class AccessClientAdapter {
     this.authorizationTimeout_ = this.buildConfigAuthorizationTimeout_(
         configJson);
 
-    /** @const @private {!Xhr} */
+    /** @const @private {!../../../src/service/xhr-impl.Xhr} */
     this.xhr_ = xhrFor(ampdoc.win);
 
-    /** @const @private {!Timer} */
+    /** @const @private {!../../../src/service/timer-impl.Timer} */
     this.timer_ = timerFor(ampdoc.win);
   }
 
diff --git a/extensions/amp-access/0.1/amp-access-other.js b/extensions/amp-access/0.1/amp-access-other.js
index f11bb3f232bb..dcfc41d698c0 100644
--- a/extensions/amp-access/0.1/amp-access-other.js
+++ b/extensions/amp-access/0.1/amp-access-other.js
@@ -21,19 +21,19 @@ import {isProxyOrigin} from '../../../src/url';
 const TAG = 'amp-access-other';
 
 
-/** @implements {AccessTypeAdapterDef} */
+/** @implements {./amp-access.AccessTypeAdapterDef} */
 export class AccessOtherAdapter {
 
   /**
    * @param {!../../../src/service/ampdoc-impl.AmpDoc} ampdoc
    * @param {!JsonObject} configJson
-   * @param {!AccessTypeAdapterContextDef} context
+   * @param {!./amp-access.AccessTypeAdapterContextDef} context
    */
   constructor(ampdoc, configJson, context) {
     /** @const */
     this.ampdoc = ampdoc;
 
-    /** @const @private {!AccessTypeAdapterContextDef} */
+    /** @const @private {!./amp-access.AccessTypeAdapterContextDef} */
     this.context_ = context;
 
     /** @private {?JsonObject} */
diff --git a/extensions/amp-access/0.1/amp-access-server-jwt.js b/extensions/amp-access/0.1/amp-access-server-jwt.js
index 229f642ce5b8..fbf519fbb1a1 100644
--- a/extensions/amp-access/0.1/amp-access-server-jwt.js
+++ b/extensions/amp-access/0.1/amp-access-server-jwt.js
@@ -17,6 +17,7 @@
 import {AccessClientAdapter} from './amp-access-client';
 import {JwtHelper} from './jwt';
 import {assertHttpsUrl} from '../../../src/url';
+import {dict} from '../../../src/utils/object';
 import {getMode} from '../../../src/mode';
 import {isArray} from '../../../src/types';
 import {isExperimentOn} from '../../../src/experiments';
@@ -72,35 +73,35 @@ const AMP_AUD = 'ampproject.org';
  *            \/
  *    Apply authorization response
  *
- * @implements {AccessTypeAdapterDef}
+ * @implements {./amp-access.AccessTypeAdapterDef}
  */
 export class AccessServerJwtAdapter {
 
   /**
    * @param {!../../../src/service/ampdoc-impl.AmpDoc} ampdoc
    * @param {!JsonObject} configJson
-   * @param {!AccessTypeAdapterContextDef} context
+   * @param {!./amp-access.AccessTypeAdapterContextDef} context
    */
   constructor(ampdoc, configJson, context) {
     /** @const */
     this.ampdoc = ampdoc;
 
-    /** @const @private {!AccessTypeAdapterContextDef} */
+    /** @const @private {!./amp-access.AccessTypeAdapterContextDef} */
     this.context_ = context;
 
     /** @private @const */
     this.clientAdapter_ = new AccessClientAdapter(ampdoc, configJson, context);
 
-    /** @private @const {!Viewer} */
+    /** @private @const {!../../../src/service/viewer-impl.Viewer} */
     this.viewer_ = viewerForDoc(ampdoc);
 
-    /** @const @private {!Xhr} */
+    /** @const @private {!../../../src/service/xhr-impl.Xhr} */
     this.xhr_ = xhrFor(ampdoc.win);
 
-    /** @const @private {!Timer} */
+    /** @const @private {!../../../src/service/timer-impl.Timer} */
     this.timer_ = timerFor(ampdoc.win);
 
-    /** @const @private {!Vsync} */
+    /** @const @private {!../../../src/service/vsync-impl.Vsync} */
     this.vsync_ = vsyncFor(ampdoc.win);
 
     const stateElement = ampdoc.getRootNode().querySelector(
@@ -183,7 +184,7 @@ export class AccessServerJwtAdapter {
   }
 
   /**
-   * @return {!Promise<{encoded:string, jwt:!JSONObject}>}
+   * @return {!Promise<{encoded:string, jwt:!JsonObject}>}
    * @private
    */
   fetchJwt_() {
@@ -235,7 +236,8 @@ export class AccessServerJwtAdapter {
     if (this.key_) {
       return Promise.resolve(this.key_);
     }
-    return this.xhr_.fetchText(this.keyUrl_).then(res => res.text());
+    return this.xhr_.fetchText(dev().assertString(this.keyUrl_))
+        .then(res => res.text());
   }
 
   /**
@@ -247,7 +249,7 @@ export class AccessServerJwtAdapter {
   }
 
   /**
-   * @param {!JSONObject} jwt
+   * @param {!JsonObject} jwt
    * @private
    */
   validateJwt_(jwt) {
@@ -298,11 +300,11 @@ export class AccessServerJwtAdapter {
       const encoded = resp.encoded;
       const jwt = resp.jwt;
       const accessData = jwt['amp_authdata'];
-      const request = serializeQueryString({
+      const request = serializeQueryString(dict({
         'url': removeFragment(this.ampdoc.win.location.href),
         'state': this.serverState_,
         'jwt': encoded,
-      });
+      }));
       dev().fine(TAG, 'Authorization request: ', this.serviceUrl_, request);
       dev().fine(TAG, '- access data: ', accessData);
       // Note that `application/x-www-form-urlencoded` is used to avoid
diff --git a/extensions/amp-access/0.1/amp-access-server.js b/extensions/amp-access/0.1/amp-access-server.js
index 272de88e8066..d2094d7eb4d4 100644
--- a/extensions/amp-access/0.1/amp-access-server.js
+++ b/extensions/amp-access/0.1/amp-access-server.js
@@ -18,6 +18,8 @@ import {AccessClientAdapter} from './amp-access-client';
 import {isExperimentOn} from '../../../src/experiments';
 import {isProxyOrigin, removeFragment} from '../../../src/url';
 import {dev} from '../../../src/log';
+import {dict} from '../../../src/utils/object';
+import {parseJson} from '../../../src/json';
 import {timerFor} from '../../../src/services';
 import {viewerForDoc} from '../../../src/services';
 import {vsyncFor} from '../../../src/services';
@@ -54,35 +56,35 @@ const TAG = 'amp-access-server';
  *            \/
  *    Apply authorization response
  *
- * @implements {AccessTypeAdapterDef}
+ * @implements {./amp-access.AccessTypeAdapterDef}
  */
 export class AccessServerAdapter {
 
   /**
    * @param {!../../../src/service/ampdoc-impl.AmpDoc} ampdoc
    * @param {!JsonObject} configJson
-   * @param {!AccessTypeAdapterContextDef} context
+   * @param {!./amp-access.AccessTypeAdapterContextDef} context
    */
   constructor(ampdoc, configJson, context) {
     /** @const */
     this.ampdoc = ampdoc;
 
-    /** @const @private {!AccessTypeAdapterContextDef} */
+    /** @const @private {!./amp-access.AccessTypeAdapterContextDef} */
     this.context_ = context;
 
     /** @private @const */
     this.clientAdapter_ = new AccessClientAdapter(ampdoc, configJson, context);
 
-    /** @private @const {!Viewer} */
+    /** @private @const {!../../../src/service/viewer-impl.Viewer} */
     this.viewer_ = viewerForDoc(ampdoc);
 
-    /** @const @private {!Xhr} */
+    /** @const @private {!../../../src/service/xhr-impl.Xhr} */
     this.xhr_ = xhrFor(ampdoc.win);
 
-    /** @const @private {!Timer} */
+    /** @const @private {!../../../src/service/timer-impl.Timer} */
     this.timer_ = timerFor(ampdoc.win);
 
-    /** @const @private {!Vsync} */
+    /** @const @private {!../../../src/service/vsync-impl.Vsync} */
     this.vsync_ = vsyncFor(ampdoc.win);
 
     const stateElement = ampdoc.getRootNode().querySelector(
@@ -142,11 +144,11 @@ export class AccessServerAdapter {
           requestVars[k] = String(vars[k]);
         }
       }
-      const request = {
+      const request = dict({
         'url': removeFragment(this.ampdoc.win.location.href),
         'state': this.serverState_,
         'vars': requestVars,
-      };
+      });
       dev().fine(TAG, 'Authorization request: ', this.serviceUrl_, request);
       // Note that `application/x-www-form-urlencoded` is used to avoid
       // CORS preflight request.
@@ -165,7 +167,7 @@ export class AccessServerAdapter {
       const accessDataString = dev().assert(
           responseDoc.querySelector('script[id="amp-access-data"]'),
           'No authorization data available').textContent;
-      const accessData = JSON.parse(accessDataString);
+      const accessData = parseJson(accessDataString);
       dev().fine(TAG, '- access data: ', accessData);
 
       return this.replaceSections_(responseDoc).then(() => {
diff --git a/extensions/amp-access/0.1/amp-access-vendor.js b/extensions/amp-access/0.1/amp-access-vendor.js
index d56833d26a06..22b3b9eeac88 100644
--- a/extensions/amp-access/0.1/amp-access-vendor.js
+++ b/extensions/amp-access/0.1/amp-access-vendor.js
@@ -15,6 +15,7 @@
  */
 
 import {dev, user} from '../../../src/log';
+import './access-vendor';
 
 /** @const {string} */
 const TAG = 'amp-access-vendor';
@@ -25,7 +26,7 @@ const TAG = 'amp-access-vendor';
  * interface and delivered via a separate extension. The vendor implementation
  * mainly requires two method: `authorize` and `pingback`. The actual
  * extension is registered via `registerVendor` method.
- * @implements {AccessTypeAdapterDef}
+ * @implements {./amp-access.AccessTypeAdapterDef}
  */
 export class AccessVendorAdapter {
 
@@ -47,9 +48,11 @@ export class AccessVendorAdapter {
     /** @const @private {boolean} */
     this.isPingbackEnabled_ = !configJson['noPingback'];
 
+    /** @private {?function(!./access-vendor.AccessVendor)} */
+    this.vendorResolve_ = null;
+
     /** @const @private {!Promise<!./access-vendor.AccessVendor>} */
     this.vendorPromise_ = new Promise(resolve => {
-      /** @private {function(!./access-vendor.AccessVendor)|undefined} */
       this.vendorResolve_ = resolve;
     });
   }
@@ -61,7 +64,7 @@ export class AccessVendorAdapter {
 
   /**
    * @param {string} name
-   * @param {./access-vendor.AccessVendor} vendor
+   * @param {!./access-vendor.AccessVendor} vendor
    */
   registerVendor(name, vendor) {
     user().assert(this.vendorResolve_, 'Vendor has already been registered');
@@ -69,7 +72,7 @@ export class AccessVendorAdapter {
         'Vendor "%s" doesn\'t match the configured vendor "%s"',
         name, this.vendorName_);
     this.vendorResolve_(vendor);
-    this.vendorResolve_ = undefined;
+    this.vendorResolve_ = null;
   }
 
   /** @override */
diff --git a/extensions/amp-access/0.1/amp-access.js b/extensions/amp-access/0.1/amp-access.js
index 0c0cbffba9d5..ae74c7106f8c 100644
--- a/extensions/amp-access/0.1/amp-access.js
+++ b/extensions/amp-access/0.1/amp-access.js
@@ -34,6 +34,7 @@ import {isExperimentOn} from '../../../src/experiments';
 import {isObject} from '../../../src/types';
 import {listenOnce} from '../../../src/event-helper';
 import {dev, user} from '../../../src/log';
+import {dict} from '../../../src/utils/object';
 import {getLoginUrl, openLoginDialog} from './login-dialog';
 import {parseQueryString} from '../../../src/url';
 import {performanceForOrNull} from '../../../src/services';
@@ -103,17 +104,19 @@ export class AccessService {
     this.isJwtEnabled_ = isExperimentOn(ampdoc.win, 'amp-access-jwt');
 
     /** @const @private {!Element} */
-    this.accessElement_ = accessElement;
+    this.accessElement_ = dev().assertElement(accessElement);
 
     const configJson = tryParseJson(this.accessElement_.textContent, e => {
       throw user().createError('Failed to parse "amp-access" JSON: ' + e);
     });
 
     /** @const @private {!AccessType} */
-    this.type_ = this.buildConfigType_(configJson);
+    this.type_ = this.buildConfigType_(/** @type {!JsonObject} */ (
+        configJson));
 
-    /** @const @private {!Object<string, string>} */
-    this.loginConfig_ = this.buildConfigLoginMap_(configJson);
+    /** @const @private {!JsonObject} */
+    this.loginConfig_ = this.buildConfigLoginMap_(/** @type {!JsonObject} */ (
+        configJson));
 
     /** @const @private {!JsonObject} */
     this.authorizationFallbackResponse_ =
@@ -125,33 +128,33 @@ export class AccessService {
     /** @const @private {string} */
     this.pubOrigin_ = getSourceOrigin(ampdoc.win.location);
 
-    /** @const @private {!Timer} */
+    /** @const @private {!../../../src/service/timer-impl.Timer} */
     this.timer_ = timerFor(ampdoc.win);
 
-    /** @const @private {!Vsync} */
+    /** @const @private {!../../../src/service/vsync-impl.Vsync} */
     this.vsync_ = vsyncFor(ampdoc.win);
 
-    /** @const @private {!UrlReplacements} */
+    /** @const @private {!../../../src/service/url-replacements-impl.UrlReplacements} */
     this.urlReplacements_ = urlReplacementsForDoc(ampdoc);
 
     // TODO(dvoytenko, #3742): This will refer to the ampdoc once AccessService
     // is migrated to ampdoc as well.
-    /** @private @const {!Cid} */
+    /** @private @const {!Promise<!../../../src/service/cid-impl.Cid>} */
     this.cid_ = cidForDoc(ampdoc);
 
-    /** @private @const {!Viewer} */
+    /** @private @const {!../../../src/service/viewer-impl.Viewer} */
     this.viewer_ = viewerForDoc(ampdoc);
 
-    /** @private @const {!Viewport} */
+    /** @private @const {!../../../src/service/viewport-impl.Viewport} */
     this.viewport_ = viewportForDoc(ampdoc);
 
-    /** @private @const {!Templates} */
+    /** @private @const {!../../../src/service/template-impl.Templates} */
     this.templates_ = templatesFor(ampdoc.win);
 
-    /** @private @const {!Resources} */
+    /** @private @const {!../../../src/service/resources-impl.Resources} */
     this.resources_ = resourcesForDoc(ampdoc);
 
-    /** @private @const {?Performance} */
+    /** @private @const {?../../../src/service/performance-impl.Performance} */
     this.performance_ = performanceForOrNull(ampdoc.win);
 
     /** @private @const {function(string):Promise<string>} */
@@ -167,9 +170,11 @@ export class AccessService {
     this.signIn_ = new SignInProtocol(ampdoc, this.viewer_, this.pubOrigin_,
         configJson);
 
+    /** @private {?Function} */
+    this.firstAuthorizationResolver_ = null;
+
     /** @const @private {!Promise} */
     this.firstAuthorizationPromise_ = new Promise(resolve => {
-      /** @private {!Promise} */
       this.firstAuthorizationResolver_ = resolve;
     });
 
@@ -200,7 +205,7 @@ export class AccessService {
 
   /**
    * @param {string} name
-   * @param {./access-vendor.AccessVendor} vendor
+   * @param {!./access-vendor.AccessVendor} vendor
    */
   registerVendor(name, vendor) {
     user().assert(this.type_ == AccessType.VENDOR,
@@ -232,7 +237,7 @@ export class AccessService {
         }
         return new AccessServerAdapter(this.ampdoc, configJson, context);
       case AccessType.VENDOR:
-        return new AccessVendorAdapter(this.ampdoc, configJson, context);
+        return new AccessVendorAdapter(this.ampdoc, configJson);
       case AccessType.OTHER:
         return new AccessOtherAdapter(this.ampdoc, configJson, context);
     }
@@ -274,12 +279,12 @@ export class AccessService {
 
   /**
    * @param {!JsonObject} configJson
-   * @return {?Object<string, string>}
+   * @return {!JsonObject}
    * @private
    */
   buildConfigLoginMap_(configJson) {
     const loginConfig = configJson['login'];
-    const loginMap = {};
+    const loginMap = dict();
     if (!loginConfig) {
       // Ignore: in some cases login config is not necessary.
     } else if (typeof loginConfig == 'string') {
@@ -295,7 +300,7 @@ export class AccessService {
 
     // Check that all URLs are valid.
     for (const k in loginMap) {
-      assertHttpsUrl(loginMap[k]);
+      assertHttpsUrl(loginMap[k], this.accessElement_);
     }
     return loginMap;
   }
@@ -375,10 +380,10 @@ export class AccessService {
 
   /** @private */
   broadcastReauthorize_() {
-    this.viewer_.broadcast({
+    this.viewer_.broadcast(dict({
       'type': 'amp-access-reauthorize',
       'origin': this.pubOrigin_,
-    });
+    }));
   }
 
   /**
@@ -547,7 +552,7 @@ export class AccessService {
   }
 
   /**
-   * @param {!JsonObjectDef} response
+   * @param {!JsonObject} response
    * @return {!Promise}
    * @private
    */
@@ -562,7 +567,7 @@ export class AccessService {
 
   /**
    * @param {!Element} element
-   * @param {!JsonObjectDef} response
+   * @param {!JsonObject} response
    * @return {!Promise}
    * @private
    */
@@ -603,8 +608,8 @@ export class AccessService {
   /**
    * Discovers and renders templates.
    * @param {!Element} element
-   * @param {!JsonObjectDef} response
-   * @return {!Promise}
+   * @param {!JsonObject} response
+   * @return {?Promise}
    * @private
    */
   renderTemplates_(element, response) {
@@ -627,7 +632,7 @@ export class AccessService {
   /**
    * @param {!Element} element
    * @param {!Element} templateOrPrev
-   * @param {!JsonObjectDef} response
+   * @param {!JsonObject} response
    * @return {!Promise}
    * @private
    */
@@ -776,7 +781,7 @@ export class AccessService {
   }
 
   /**
-   * @param {!ActionInvocation} invocation
+   * @param {!../../../src/service/action-impl.ActionInvocation} invocation
    * @private
    */
   handleAction_(invocation) {
@@ -910,7 +915,7 @@ export class AccessService {
   }
 
   /**
-   * @return {?Promise<!{type: string, url: string}>}
+   * @return {?Promise<!Array<!{type: string, url: string}>>}
    * @private
    */
   buildLoginUrls_() {
@@ -938,13 +943,13 @@ export class AccessService {
  *       !Promise<!Object<string, *>>
  * }}
  */
-let AccessTypeAdapterContextDef;
+export let AccessTypeAdapterContextDef;
 
 
 /**
  * @interface
  */
-class AccessTypeAdapterDef {
+export class AccessTypeAdapterDef {
 
   /**
    * @return {!JsonObject}
diff --git a/extensions/amp-access/0.1/jwt.js b/extensions/amp-access/0.1/jwt.js
index c7bcf10db61c..89cf703c139d 100644
--- a/extensions/amp-access/0.1/jwt.js
+++ b/extensions/amp-access/0.1/jwt.js
@@ -24,8 +24,8 @@ import {tryParseJson} from '../../../src/json';
 
 /**
  * @typedef {{
- *   header: !JSONObject,
- *   payload: !JSONObject,
+ *   header: (?JsonObject|undefined),
+ *   payload: (?JsonObject|undefined),
  *   verifiable: string,
  *   sig: string,
  * }}
@@ -48,7 +48,7 @@ export class JwtHelper {
 
     /**
      * Might be `null` if the platform does not support Crypto Subtle.
-     * @const @private {?SubtleCrypto}
+     * @const @private {?webCrypto.SubtleCrypto}
      */
     this.subtle_ = win.crypto &&
         (win.crypto.subtle || win.crypto.webkitSubtle) || null;
@@ -57,7 +57,7 @@ export class JwtHelper {
   /**
    * Decodes JWT token and returns its payload.
    * @param {string} encodedToken
-   * @return {!JSONObject}
+   * @return {?JsonObject|undefined}
    */
   decode(encodedToken) {
     return this.decodeInternal_(encodedToken).payload;
@@ -75,7 +75,7 @@ export class JwtHelper {
    * Decodes HWT token and verifies its signature.
    * @param {string} encodedToken
    * @param {!Promise<string>} pemPromise
-   * @return {!Promise<!JSONObject>}
+   * @return {!Promise<!JsonObject>}
    */
   decodeAndVerify(encodedToken, pemPromise) {
     if (!this.subtle_) {
@@ -136,7 +136,7 @@ export class JwtHelper {
 
   /**
    * @param {!Promise<string>} pemPromise
-   * @return {!Promise<!CryptoKey>}
+   * @return {!Promise<!webCrypto.CryptoKey>}
    */
   importKey_(pemPromise) {
     return pemPromise.then(pem => {
diff --git a/extensions/amp-access/0.1/login-dialog.js b/extensions/amp-access/0.1/login-dialog.js
index 83dc551bd2f3..cd33cf7d4d3b 100644
--- a/extensions/amp-access/0.1/login-dialog.js
+++ b/extensions/amp-access/0.1/login-dialog.js
@@ -15,12 +15,13 @@
  */
 
 import {getMode} from '../../../src/mode';
-import {listen} from '../../../src/event-helper';
+import {getData, listen} from '../../../src/event-helper';
 import {dev, user} from '../../../src/log';
 import {openWindowDialog} from '../../../src/dom';
 import {parseUrl} from '../../../src/url';
 import {viewerForDoc} from '../../../src/services';
 import {urls} from '../../../src/config';
+import {dict} from '../../../src/utils/object';
 
 /** @const */
 const TAG = 'amp-access-login';
@@ -71,11 +72,11 @@ export function getLoginUrl(ampdoc, urlOrPromise) {
  */
 class ViewerLoginDialog {
   /**
-   * @param {!Viewer} viewer
+   * @param {!../../../src/service/viewer-impl.Viewer} viewer
    * @param {string|!Promise<string>} urlOrPromise
    */
   constructor(viewer, urlOrPromise) {
-    /** @const {!Viewer} */
+    /** @const {!../../../src/service/viewer-impl.Viewer} */
     this.viewer = viewer;
 
     /** @const {string|!Promise<string>} */
@@ -107,9 +108,9 @@ class ViewerLoginDialog {
   open() {
     return this.getLoginUrl().then(loginUrl => {
       dev().fine(TAG, 'Open viewer dialog: ', loginUrl);
-      return this.viewer.sendMessageAwaitResponse('openDialog', {
+      return this.viewer.sendMessageAwaitResponse('openDialog', dict({
         'url': loginUrl,
-      });
+      }));
     });
   }
 
@@ -123,20 +124,20 @@ class ViewerLoginDialog {
 export class WebLoginDialog {
   /**
    * @param {!Window} win
-   * @param {!Viewer} viewer
+   * @param {!../../../src/service/viewer-impl.Viewer} viewer
    * @param {string|!Promise<string>} urlOrPromise
    */
   constructor(win, viewer, urlOrPromise) {
     /** @const {!Window} */
     this.win = win;
 
-    /** @const {!Viewer} */
+    /** @const {!../../../src/service/viewer-impl.Viewer} */
     this.viewer = viewer;
 
     /** @const {string|!Promise<string>} */
     this.urlOrPromise = urlOrPromise;
 
-    /** @private {?function(string)} */
+    /** @private {?function(?string)} */
     this.resolve_ = null;
 
     /** @private {?function(*)} */
@@ -151,7 +152,7 @@ export class WebLoginDialog {
     /** @private {?number} */
     this.heartbeatInterval_ = null;
 
-    /** @private {?Unlisten} */
+    /** @private {?UnlistenDef} */
     this.messageUnlisten_ = null;
   }
 
@@ -284,18 +285,18 @@ export class WebLoginDialog {
       if (e.origin != returnOrigin) {
         return;
       }
-      if (!e.data || e.data.sentinel != 'amp') {
+      if (!getData(e) || getData(e)['sentinel'] != 'amp') {
         return;
       }
-      dev().fine(TAG, 'Received message from dialog: ', e.data);
-      if (e.data.type == 'result') {
+      dev().fine(TAG, 'Received message from dialog: ', getData(e));
+      if (getData(e)['type'] == 'result') {
         if (this.dialog_) {
-          this.dialog_./*OK*/postMessage({
-            sentinel: 'amp',
-            type: 'result-ack',
-          }, returnOrigin);
+          this.dialog_./*OK*/postMessage(dict({
+            'sentinel': 'amp',
+            'type': 'result-ack',
+          }), returnOrigin);
         }
-        this.loginDone_(e.data.result);
+        this.loginDone_(getData(e)['result']);
       }
     });
   }
diff --git a/extensions/amp-access/0.1/signin.js b/extensions/amp-access/0.1/signin.js
index c01527339379..d09464692430 100644
--- a/extensions/amp-access/0.1/signin.js
+++ b/extensions/amp-access/0.1/signin.js
@@ -17,6 +17,7 @@
 import {isArray} from '../../../src/types';
 import {isExperimentOn} from '../../../src/experiments';
 import {user} from '../../../src/log';
+import {dict} from '../../../src/utils/object';
 
 
 /** @const */
@@ -58,15 +59,15 @@ export class SignInProtocol {
 
   /**
    * @param {!../../../src/service/ampdoc-impl.AmpDoc} ampdoc
-   * @param {!Viewer} viewer
+   * @param {!../../../src/service/viewer-impl.Viewer} viewer
    * @param {string} pubOrigin
-   * @param {!JSONObject} configJson
+   * @param {!JsonObject} configJson
    */
   constructor(ampdoc, viewer, pubOrigin, configJson) {
     /** @const */
     this.ampdoc = ampdoc;
 
-    /** @private @const {!Viewer} */
+    /** @private @const {!../../../src/service/viewer-impl.Viewer} */
     this.viewer_ = viewer;
 
     /** @private @const {string} */
@@ -78,10 +79,11 @@ export class SignInProtocol {
         this.viewer_.isEmbedded() &&
         this.viewer_.getParam('signin') == '1';
 
+    let acceptAccessToken;
+    let supportsSignInService;
     if (this.isEnabled_) {
 
-      /** @private @const {boolean} */
-      this.acceptAccessToken_ = !!configJson['acceptAccessToken'];
+      acceptAccessToken = !!configJson['acceptAccessToken'];
 
       const viewerSignInService = this.viewer_.getParam('signinService');
       const configSignInServices = configJson['signinServices'];
@@ -90,16 +92,17 @@ export class SignInProtocol {
             '"signinServices" must be an array');
       }
 
-      /** @private @const {boolean} */
-      this.supportsSignInService_ = configSignInServices &&
+      supportsSignInService = configSignInServices &&
           configSignInServices.indexOf(viewerSignInService) != -1;
     } else {
-      /** @private @const {boolean} */
-      this.acceptAccessToken_ = false;
-      /** @private @const {boolean} */
-      this.supportsSignInService_ = false;
+      acceptAccessToken = false;
+      supportsSignInService = false;
     }
 
+    /** @private @const {boolean} */
+    this.acceptAccessToken_ = acceptAccessToken;
+    /** @private @const {boolean} */
+    this.supportsSignInService_ = supportsSignInService;
     /** @private {?Promise<?string>} */
     this.accessTokenPromise_ = null;
   }
@@ -138,9 +141,9 @@ export class SignInProtocol {
     }
     if (!this.accessTokenPromise_) {
       this.accessTokenPromise_ = this.viewer_.sendMessageAwaitResponse(
-          'getAccessTokenPassive', {
-            origin: this.pubOrigin_,
-          }).then(resp => {
+          'getAccessTokenPassive', dict({
+            'origin': this.pubOrigin_,
+          })).then(resp => {
             return /** @type {?string} */ (resp);
           }).catch(reason => {
             user().error(TAG, 'Failed to retrieve access token: ', reason);
@@ -184,10 +187,10 @@ export class SignInProtocol {
     if (!authorizationCode) {
       return null;
     }
-    return this.viewer_.sendMessageAwaitResponse('storeAccessToken', {
-      origin: this.pubOrigin_,
-      authorizationCode,
-    }).then(resp => {
+    return this.viewer_.sendMessageAwaitResponse('storeAccessToken', dict({
+      'origin': this.pubOrigin_,
+      'authorizationCode': authorizationCode,
+    })).then(resp => {
       const accessToken = /** @type {?string} */ (resp);
       this.updateAccessToken_(accessToken);
       return accessToken;
@@ -217,10 +220,10 @@ export class SignInProtocol {
     if (!this.supportsSignInService_) {
       return null;
     }
-    return this.viewer_.sendMessageAwaitResponse('requestSignIn', {
-      origin: this.pubOrigin_,
-      url,
-    }).then(resp => {
+    return this.viewer_.sendMessageAwaitResponse('requestSignIn', dict({
+      'origin': this.pubOrigin_,
+      'url': url,
+    })).then(resp => {
       const accessToken = /** @type {?string} */ (resp);
       this.updateAccessToken_(accessToken);
       // Return empty dialog result.
diff --git a/extensions/amp-analytics/0.1/test/test-amp-analytics.js b/extensions/amp-analytics/0.1/test/test-amp-analytics.js
index 389b08aea628..39dc30063421 100644
--- a/extensions/amp-analytics/0.1/test/test-amp-analytics.js
+++ b/extensions/amp-analytics/0.1/test/test-amp-analytics.js
@@ -177,8 +177,8 @@ describe('amp-analytics', function() {
    * inline config and iframePings/optout are not allowed to be used without
    * AMP team's approval.
    *
-   * @param {!JSONObject} config The inline config to update.
-   * @return {!JSONObject}
+   * @param {!JsonObject} config The inline config to update.
+   * @return {!JsonObject}
    */
   function clearVendorOnlyConfig(config) {
     for (const t in config.triggers) {
diff --git a/gulpfile.js b/gulpfile.js
index 6fcd099e0ff2..7d6c06b9656b 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -47,8 +47,8 @@ var extensionAliasFilePath = {};
 
 // Each extension and version must be listed individually here.
 declareExtension('amp-3q-player', '0.1', false);
-declareExtension('amp-access', '0.1', true, 'NO_TYPE_CHECK');
-declareExtension('amp-access-laterpay', '0.1', true, 'NO_TYPE_CHECK');
+declareExtension('amp-access', '0.1', true);
+declareExtension('amp-access-laterpay', '0.1', true);
 declareExtension('amp-accordion', '0.1', false);
 declareExtension('amp-ad', '0.1', true);
 declareExtension('amp-ad-network-adsense-impl', 0.1, false);
@@ -144,12 +144,8 @@ declareExtensionVersionAlias(
  * @param {string} version E.g. 0.1
  * @param {boolean|!Object} hasCssOrOptions Whether the extension comes with CSS
  *   or an extension options object.
- * @param {string=} opt_noTypeCheck Whether not to check types.
- *     No new extension must pass this.
- * @param {!Array<string>=} opt_extraGlobs
  */
-function declareExtension(name, version, hasCssOrOptions, opt_noTypeCheck,
-    opt_extraGlobs) {
+function declareExtension(name, version, hasCssOrOptions) {
   var hasCss = false;
   var options = {};
   if (typeof hasCssOrOptions == 'boolean') {
@@ -161,9 +157,6 @@ function declareExtension(name, version, hasCssOrOptions, opt_noTypeCheck,
     name: name,
     version: version,
     hasCss: hasCss,
-    // Only grandfathered for access
-    noTypeCheck: (!!opt_noTypeCheck && /access/.test(name)),
-    extraGlobs: opt_extraGlobs,
   }, options);
 }
 
diff --git a/package.json b/package.json
index bfaf6a7eec07..58a7ba0dd7a1 100644
--- a/package.json
+++ b/package.json
@@ -86,7 +86,7 @@
     "karma-mocha": "0.2.2",
     "karma-safari-launcher": "0.1.1",
     "karma-sauce-launcher": "1.1.0",
-    "karma-sinon-chai": "1.2.0",
+    "karma-sinon-chai": "1.2.3",
     "lazypipe": "1.0.1",
     "lolex": "1.4.0",
     "markdown-link-check": "^3.0.3",
@@ -101,7 +101,7 @@
     "pretty-bytes": "2.0.1",
     "request": "2.73.0",
     "rimraf": "2.5.1",
-    "sinon": "1.17.3",
+    "sinon": "1.17.7",
     "sinon-chai": "2.8.0",
     "text-table": "0.2.0",
     "through2": "2.0.0",
diff --git a/src/service/url-replacements-impl.js b/src/service/url-replacements-impl.js
index 3610f1973e7d..657c192aede5 100644
--- a/src/service/url-replacements-impl.js
+++ b/src/service/url-replacements-impl.js
@@ -74,7 +74,8 @@ export class GlobalVariableSource extends VariableSource {
 
     /**
      * @private
-     * @const {function(!./ampdoc-impl.AmpDoc):!Promise<?AccessService>}
+     * @const {function(!./ampdoc-impl.AmpDoc):
+     *     !Promise<?../../extensions/amp-access/0.1/amp-access.AccessService>}
      */
     this.getAccessService_ = accessServiceForDocOrNull;
 
@@ -476,7 +477,8 @@ export class GlobalVariableSource extends VariableSource {
   /**
    * Resolves the value via access service. If access service is not configured,
    * the resulting value is `null`.
-   * @param {function(!AccessService):(T|!Promise<T>)} getter
+   * @param {function(!../../extensions/amp-access/0.1/amp-access.AccessService
+   *     ):(T|!Promise<T>)} getter
    * @param {string} expr
    * @return {T|null}
    * @template T
diff --git a/src/services.js b/src/services.js
index 3718ab563cb0..f227cfb3c19f 100644
--- a/src/services.js
+++ b/src/services.js
@@ -33,22 +33,24 @@ import {
 /**
  * Returns a promise for the Access service.
  * @param {!Node|!./service/ampdoc-impl.AmpDoc} nodeOrDoc
- * @return {!Promise<!AccessService>}
+ * @return {!Promise<!../extensions/amp-access/0.1/amp-access.AccessService>}
  */
 export function accessServiceForDoc(nodeOrDoc) {
-  return /** @type {!Promise<!AccessService>} */ (
-      getElementServiceForDoc(nodeOrDoc, 'access', 'amp-access'));
+  return (/** @type {!Promise<
+      !../extensions/amp-access/0.1/amp-access.AccessService>} */ (
+      getElementServiceForDoc(nodeOrDoc, 'access', 'amp-access')));
 }
 
 /**
  * Returns a promise for the Access service or a promise for null if the service
  * is not available on the current page.
  * @param {!Node|!./service/ampdoc-impl.AmpDoc} nodeOrDoc
- * @return {!Promise<?AccessService>}
+ * @return {!Promise<?../extensions/amp-access/0.1/amp-access.AccessService>}
  */
 export function accessServiceForDocOrNull(nodeOrDoc) {
-  return /** @type {!Promise<?AccessService>} */ (
-      getElementServiceIfAvailableForDoc(nodeOrDoc, 'access', 'amp-access'));
+  return (/** @type {
+      !Promise<?../extensions/amp-access/0.1/amp-access.AccessService>} */ (
+      getElementServiceIfAvailableForDoc(nodeOrDoc, 'access', 'amp-access')));
 }
 
 /**
diff --git a/yarn.lock b/yarn.lock
index 62b5153dceb4..70ae1ee101a1 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3537,7 +3537,7 @@ gulp-uglify@2.0.1:
     uglify-save-license "^0.4.1"
     vinyl-sourcemaps-apply "^0.2.0"
 
-gulp-util@3.0.7, gulp-util@^3.0.0, gulp-util@^3.0.3, gulp-util@^3.0.6, gulp-util@^3.0.7:
+gulp-util@3.0.7, gulp-util@^3.0.0, gulp-util@^3.0.6:
   version "3.0.7"
   resolved "https://registry.yarnpkg.com/gulp-util/-/gulp-util-3.0.7.tgz#78925c4b8f8b49005ac01a011c557e6218941cbb"
   dependencies:
@@ -3573,7 +3573,7 @@ gulp-util@^2.2.14, gulp-util@^2.2.19:
     through2 "^0.5.0"
     vinyl "^0.2.1"
 
-gulp-util@^3.0.8:
+gulp-util@^3.0.3, gulp-util@^3.0.7, gulp-util@^3.0.8:
   version "3.0.8"
   resolved "https://registry.yarnpkg.com/gulp-util/-/gulp-util-3.0.8.tgz#0054e1e744502e27c04c187c3ecc505dd54bbb4f"
   dependencies:
@@ -4291,14 +4291,7 @@ js-tokens@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-3.0.0.tgz#a2f2a969caae142fb3cd56228358c89366957bd1"
 
-js-yaml@^3.2.6:
-  version "3.7.0"
-  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.7.0.tgz#5c967ddd837a9bfdca5f2de84253abe8a1c03b80"
-  dependencies:
-    argparse "^1.0.7"
-    esprima "^2.6.0"
-
-js-yaml@^3.5.1, js-yaml@^3.8.2:
+js-yaml@^3.2.6, js-yaml@^3.5.1, js-yaml@^3.8.2:
   version "3.8.4"
   resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.8.4.tgz#520b4564f86573ba96662af85a8cafa7b4b5a6f6"
   dependencies:
@@ -4472,9 +4465,11 @@ karma-sauce-launcher@1.1.0:
     saucelabs "^1.3.0"
     wd "^1.0.0"
 
-karma-sinon-chai@1.2.0:
-  version "1.2.0"
-  resolved "https://registry.yarnpkg.com/karma-sinon-chai/-/karma-sinon-chai-1.2.0.tgz#2a3ab690ce55425a96cb96e441ab3d8633670624"
+karma-sinon-chai@1.2.3:
+  version "1.2.3"
+  resolved "https://registry.yarnpkg.com/karma-sinon-chai/-/karma-sinon-chai-1.2.3.tgz#93dfeadfdcc64dbde0b92ae069f39349851124ba"
+  dependencies:
+    lolex "^1.5.0"
 
 karma@1.7.0:
   version "1.7.0"
@@ -4930,6 +4925,10 @@ lolex@1.4.0:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/lolex/-/lolex-1.4.0.tgz#2f2712b1bc180de9ddcc5d3a7a96ef3c0bb162ad"
 
+lolex@^1.5.0:
+  version "1.6.0"
+  resolved "https://registry.yarnpkg.com/lolex/-/lolex-1.6.0.tgz#3a9a0283452a47d7439e72731b9e07d7386e49f6"
+
 longest@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/longest/-/longest-1.0.1.tgz#30a0b2da38f73770e8294a0d22e6625ed77d0097"
@@ -6917,9 +6916,9 @@ sinon-chai@2.8.0:
   version "2.8.0"
   resolved "https://registry.yarnpkg.com/sinon-chai/-/sinon-chai-2.8.0.tgz#432a9bbfd51a6fc00798f4d2526a829c060687ac"
 
-sinon@1.17.3:
-  version "1.17.3"
-  resolved "https://registry.yarnpkg.com/sinon/-/sinon-1.17.3.tgz#44d64bc748d023880046c1543cefcea34c47d17e"
+sinon@1.17.7:
+  version "1.17.7"
+  resolved "https://registry.yarnpkg.com/sinon/-/sinon-1.17.7.tgz#4542a4f49ba0c45c05eb2e9dd9d203e2b8efe0bf"
   dependencies:
     formatio "1.1.1"
     lolex "1.3.2"