added note about PBS rejecting auctions for bad params (prebid#1407)

Author: bretg

dev-docs/bidders/prebidServer.md

@@ -3,20 +3,30 @@ layout: bidder
 title: Prebid Server
 description: Prebid Server S2S Adaptor
 biddercode: prebidServer
-biddercode_longer_than_12: true
 hide: true
-media_types: video
+media_types: banner, video
 gdpr_supported: true
 ---
 
-### Sign up
+### Overview
 
-Sign up for account on [prebid.adnxs.com](https://prebid.adnxs.com)
+The Prebid Server Adapter is a meta-adapter. It's not an actual bidder, but
+rather a way to get a batch of bids from other bidders with one request.
+A request for the set of auctions is sent to Prebid Server, which performs
+all the auctions server side (S2S), responding in time for Prebid.js to
+send the results to the ad server. This lightens the performance load on the user's device.
 
 ### Bid Params
 
 Bid params are sourced from the adapter configurations set for client side. These do not need to change for Prebid Server.
 
+{: .alert.alert-warning :}
+**Errors in bidder parameters will cause Prebid Server to reject the
+entire request.** The Prebid Server philosophy is to avoid silent failures --
+we assume you will test changes, and that it will be easier to notice a
+4xx error coming from the server than a silent failure where it skips just
+the bad parameter.
+
 ### Configuration
 To enable prebid server, set the following configuration.
 
@@ -25,7 +35,8 @@ pbjs.setConfig({
     s2sConfig: {
         accountId : '12345',
         bidders : ['appnexus','pubmatic', 'rubicon'],
-        defaultVendor: 'appnexus'
+        defaultVendor: 'appnexus',
+        timeout: 300
     }
 });
 ```
@@ -34,16 +45,17 @@ Configuration options
 {: .table .table-bordered .table-striped }
 | Field        | Type          | Required? | Description                                                              |
 |--------------+---------------+-----------+--------------------------------------------------------------------------|
-| `accountId`  | String        | X         | Prebid Server account ID.                                                |
-| `bidders`    | Array[String] | X         | List of bidder codes; must have been enabled during Prebid.js build.     |
-| `defaultVendor` | String     |           | Automatically includes all following options in the config with vendor's default values.  Individual properties can be overridden by including them in the config along with this setting. |
-| `enabled`    | Boolean       | X         | Enables S2S; default: `false`.                                           |
-| `endpoint`   | String        | X         | Set the endpoint. For example: `https://prebid.adnxs.com/pbs/v1/openrtb2/auction` |
-| `timeout`    | Number        |           | Bidder timeout, in milliseconds; default: `1000`.                         |
-| `syncEndpoint` | String     |           | Configures the user-sync endpoint. Highly recommended.                    |
-| `adapter`    | String        |           | Adapter code; default: `"prebidServer"`.                                  |
-| `secure`     | Integer       |           | Override Prebid Server's determination of whether the request needs secure assets. Set to `1` to force secure assets on the response, or `0` for non-secure assets. |
-| `adapterOptions` | Object       |           | Arguments will be added to resulting OpenRTB payload to Prebid Server. |
+| `accountId`  | String        | yes         | Prebid Server account ID.                                                |
+| `bidders`    | Array[String] | yes         | List of bidder codes; must have been enabled during Prebid.js build.     |
+| `defaultVendor` | String     | no          | Automatically includes all following options in the config with vendor's default values.  Individual properties can be overridden by including them in the config along with this setting. |
+| `enabled`    | Boolean       | no         | Enables S2S; default: `false` (`true` when defaultVendor is set).                                           |
+| `endpoint`   | String        | no         | Set the endpoint. For example: `https://prebid.adnxs.com/pbs/v1/openrtb2/auction` |
+| `timeout`    | Number        | no         | Bidder timeout, in milliseconds; default: `1000`.                         |
+| `syncEndpoint` | String     | no       | Configures the user-sync endpoint. Highly recommended.                    |
+| `adapter`    | String        | no        | Adapter code; default: `"prebidServer"`.                                  |
+| `secure`     | Integer       | no        | Override Prebid Server's determination of whether the request needs secure assets. Set to `1` to force secure assets on the response, or `0` for non-secure assets. |
+| `adapterOptions` | Object       | no        | Arguments will be added to resulting OpenRTB payload to Prebid Server. |
+| `extPrebid` | Object       | no        | Arguments will be added to resulting OpenRTB payload to Prebid Server. |
 
 ### Examples
 
@@ -95,4 +107,4 @@ var adUnits = [{
         }
     }
 }];
-```
+```

dev-docs/publisher-api-reference.md

@@ -1579,6 +1579,13 @@ Additional information of these properties:
 - When using `defaultVendor` option, `accountId` and `bidders` properties still need to be defined.
 - If the `s2sConfig` timeout is greater than the Prebid.js timeout, the `s2sConfig` timeout will be automatically adjusted to 75% of the Prebid.js timeout in order to fit within the auction process.
 
+{: .alert.alert-warning :}
+**Errors in bidder parameters will cause Prebid Server to reject the
+entire request.** The Prebid Server philosophy is to avoid silent failures --
+we assume you will test changes, and that it will be easier to notice a
+4xx error coming from the server than a silent failure where it skips just
+the bad parameter.
+
 **Video via s2sConfig**
 
 Supporting video through the Server-to-Server route can be done by providing a couple of extra arguments on the `extPrebid` object. e.g.