diff --git a/packages/@aws-cdk/core/lib/custom-resource-provider/custom-resource-provider.ts b/packages/@aws-cdk/core/lib/custom-resource-provider/custom-resource-provider.ts
index 013c1f49b8ab8..c4423051ac6ca 100644
--- a/packages/@aws-cdk/core/lib/custom-resource-provider/custom-resource-provider.ts
+++ b/packages/@aws-cdk/core/lib/custom-resource-provider/custom-resource-provider.ts
@@ -111,8 +111,26 @@ export enum CustomResourceProviderRuntime {
 }
 
 /**
- * An AWS-Lambda backed custom resource provider.
+ * An AWS-Lambda backed custom resource provider, for CDK Construct Library constructs
  *
+ * This is a provider for `CustomResource` constructs, backed by an AWS Lambda
+ * Function. It only supports NodeJS runtimes.
+ *
+ * **This is not a generic custom resource provider class**. It is specifically
+ * intended to be used only by constructs in the AWS CDK Construct Library, and
+ * only exists here because of reverse dependency issues (for example, it cannot
+ * use `iam.PolicyStatement` objects, since the `iam` library already depends on
+ * the CDK `core` library and we cannot have cyclic dependencies).
+ *
+ * If you are not writing constructs for the AWS Construct Library, you should
+ * use the `Provider` class in the `custom-resources` module instead, which has
+ * a better API and supports all Lambda runtimes, not just Node.
+ *
+ * N.B.: When you are writing Custom Resource Providers, there are a number of
+ * lifecycle events you have to pay attention to. These are documented in the
+ * README of the `custom-resources` module. Be sure to give the documentation
+ * in that module a read, regardless of whether you end up using the Provider
+ * class in there or this one.
  */
 export class CustomResourceProvider extends CoreConstruct {
   /**
diff --git a/packages/@aws-cdk/core/lib/custom-resource.ts b/packages/@aws-cdk/core/lib/custom-resource.ts
index 261f442f1a951..a466b600fa386 100644
--- a/packages/@aws-cdk/core/lib/custom-resource.ts
+++ b/packages/@aws-cdk/core/lib/custom-resource.ts
@@ -98,11 +98,25 @@ export interface CustomResourceProps {
 }
 
 /**
- * Custom resource that is implemented using a Lambda
+ * Instantiation of a custom resource, whose implementation is provided a Provider
  *
- * As a custom resource author, you should be publishing a subclass of this class
- * that hides the choice of provider, and accepts a strongly-typed properties
- * object with the properties your provider accepts.
+ * This class is intended to be used by construct library authors. Application
+ * builder should not be able to tell whether or not a construct is backed by
+ * a custom resource, and so the use of this class should be invisible.
+ *
+ * Instead, construct library authors declare a custom construct that hides the
+ * choice of provider, and accepts a strongly-typed properties object with the
+ * properties your provider accepts.
+ *
+ * Your custom resource provider (identified by the `serviceToken` property)
+ * can be one of 4 constructs:
+ *
+ * - If you are authoring a construct library or application, we recommend you
+ *   use the `Provider` class in the `custom-resources` module.
+ * - If you are authoring a construct for the CDK's AWS Construct Library,
+ *   you should use the `CustomResourceProvider` construct in this package.
+ * - If you want full control over the provider, you can always directly use
+ *   a Lambda Function or SNS Topic by passing the ARN into `serviceToken`.
  *
  * @resource AWS::CloudFormation::CustomResource
  */
diff --git a/packages/aws-cdk/README.md b/packages/aws-cdk/README.md
index ac399df3008df..faa5a0a121fe0 100644
--- a/packages/aws-cdk/README.md
+++ b/packages/aws-cdk/README.md
@@ -19,6 +19,7 @@ Command                           | Description
 [`cdk synth`](#cdk-synthesize)    | Synthesize a CDK app to CloudFormation template(s)
 [`cdk diff`](#cdk-diff)           | Diff stacks against current state
 [`cdk deploy`](#cdk-deploy)       | Deploy a stack into an AWS account
+[`cdk watch`](#cdk-watch)         | Watches a CDK app for deployable and hotswappable changes
 [`cdk destroy`](#cdk-destroy)     | Deletes a stack from an AWS account
 [`cdk bootstrap`](#cdk-bootstrap) | Deploy a toolkit stack to support deploying large stacks & artifacts
 [`cdk doctor`](#cdk-doctor)       | Inspect the environment and produce information useful for troubleshooting
diff --git a/scripts/bump.js b/scripts/bump.js
index 3daca6711605f..943edd6da5d8b 100755
--- a/scripts/bump.js
+++ b/scripts/bump.js
@@ -4,7 +4,7 @@ const fs = require('fs');
 const path = require('path');
 const semver = require('semver');
 const ver = require('./resolve-version');
-const { exec } = require('child_process');
+const { execSync } = require('child_process');
 
 async function main() {
   const releaseAs = process.argv[2] || 'minor';
@@ -39,6 +39,23 @@ async function main() {
     // published.
     opts.prerelease = ver.prerelease || 'rc';
     console.error(`BUMP_CANDIDATE is set, so bumping version for testing (with the "${opts.prerelease}" prerelease tag)`);
+  } else {
+    // We're not running the bump in a regular pipeline, we're running it "for real" to do an actual release.
+    //
+    // In that case -- check if there have been changes since the last release. If not, there's no point in
+    // doing the release at all. Our customers won't appreciate a new version with 0 changes.
+    const prevVersion = ver.version;
+    const topLevelFileChanges = execSync(`git diff-tree --name-only v${prevVersion} HEAD`, { encoding: 'utf-8' }).split('\n').filter(x => x);
+
+    // We only release if there have been changes to files other than metadata files
+    // (for an empty release, the difference since the previous release is updates to json files and the changelog, through
+    // mergeback)
+    const anyInteresting = topLevelFileChanges.some(name => !name.includes('CHANGELOG') && !name.startsWith('version.'));
+
+    if (!anyInteresting) {
+      console.error(`No changes detected since last release -- we're done here.`);
+      return;
+    }
   }
 
   const majorVersion = semver.major(ver.version);
@@ -52,14 +69,14 @@ async function main() {
     // and creates really muddled changelogs with both v1 and v2 releases intermingled, and lots of missing data.
     // A super HACK here is to locally remove all version tags that don't match this major version prior
     // to doing the bump, and then later fetching to restore those tags.
-    await exec(`git tag -d $(git tag -l | grep -v '^v${majorVersion}.')`);
+    execSync(`git tag -d $(git tag -l | grep -v '^v${majorVersion}.')`);
 
     // Delay loading standard-version until the git tags have been pruned.
     const standardVersion = require('standard-version');
     await standardVersion(opts);
 
     // fetch back the tags, and only the tags, removed locally above
-    await exec('git fetch origin "refs/tags/*:refs/tags/*"');
+    execSync('git fetch origin "refs/tags/*:refs/tags/*"');
   } else {
     // this is incredible, but passing this option to standard-version actually makes it crash!
     // good thing we're getting rid of it...