diff --git a/weaver/1.0/IWeaver.hal b/weaver/1.0/IWeaver.hal
index 2362c29..e572123 100644
--- a/weaver/1.0/IWeaver.hal
+++ b/weaver/1.0/IWeaver.hal
@@ -16,7 +16,7 @@
 package android.hardware.weaver@1.0;
 
 /**
- * Weaver provides secure storage of secret values that can only be read if the
+ * Weaver provides secure storage of secret values that may only be read if the
  * corresponding key has been presented.
  *
  * The storage must be secure as the device's user authentication and encryption
@@ -58,20 +58,21 @@
      * The value is only returned if the provided key matches the key stored in
      * the slot. The value is never returned if the wrong key is provided.
      *
-     * Throttling is used to limit the frequency of failed read attempts. The
-     * value is only returned when throttling is not active, even if the correct
-     * key is provided. If called when throttling is active, the time until the
-     * next attempt can be made is returned.
+     * Throttling must be used to limit the frequency of failed read attempts.
+     * The value is only returned when throttling is not active, even if the
+     * correct key is provided. If called when throttling is active, the time
+     * until the next attempt can be made is returned.
      *
      * @param slotId of the slot to read from.
      * @param key that is stored in the slot.
      * @return status is OK if the value was successfully read, INCORRECT_KEY if
-     *         the key does not match the key in the slot or THROTTLE if
-     *         throttling is active.
+     *         the key does not match the key in the slot, THROTTLE if
+     *         throttling is active or FAILED if the read was unsuccessful for
+     *         another reason.
      * @return readResponse contains the value read and the timeout to wait
-     *         before making the next request. The value is undefined if the
-     *         status is not OK and the timeout is undefined if the status is
-     *         FAILED.
+     *         before making the next request. If the status is OK, value is set
+     *         to the value in the slot and timeout is 0. Otherwise, value is
+     *         empty and timeout is set accordingly.
      */
     read(uint32_t slotId, vec<uint8_t> key)
                 generates (WeaverReadStatus status,