diff --git a/.travis.yml b/.travis.yml
index 53fb0471a..44d33682b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,7 +15,7 @@ before_install:
   - mysql -e "create database IF NOT EXISTS test;" -uroot
 
 env:
-  - GCLOUD_PROJECT_NUM=0 CXX=g++-4.8
+  - GCLOUD_PROJECT=0 CXX=g++-4.8
 
 script:
   - ./bin/run-test.sh -c
diff --git a/README.md b/README.md
index 423075e50..a06376f3b 100644
--- a/README.md
+++ b/README.md
@@ -8,14 +8,14 @@
 
 > *This module is experimental, and should be used by early adopters. This module uses APIs there may be undocumented and may be subject to change without notice.*
 
-This module provides StackDriver Trace support for Node.js applications. [StackDriver Trace](https://cloud.google.com/cloud-trace/) is a feature of [Google Cloud Platform](https://cloud.google.com/) that collects latency data (traces) from your applications and displays it in near real-time in the [Google Cloud Console](https://console.cloud.google.com/?_ga=1.258049870.576536942.1443543237).
+This module provides StackDriver Trace support for Node.js applications. [StackDriver Trace](https://cloud.google.com/cloud-trace/) is a feature of [Google Cloud Platform](https://cloud.google.com/) that collects latency data (traces) from your applications and displays it in near real-time in the [Google Cloud Console][cloud-console].
 
 ![StackDriver Trace Overview](doc/images/cloud-trace-overview-page.png)
 
 ## Prerequisites
 
 1. Your application will need to be using Node.js version 0.12 or greater.
-1. You will need a project in the [Google Developers Console](https://console.cloud.google.com/project?_ga=1.258049870.576536942.1443543237). Your application can run anywhere, but the trace data is associated with a particular project.
+1. You will need a project in the [Google Developers Console][cloud-console]. Your application can run anywhere, but the trace data is associated with a particular project.
 1. [Enable the Trace API](https://console.cloud.google.com/flows/enableapi?apiid=cloudtrace) for your project.
 
 ## Installation
@@ -24,17 +24,24 @@ This module provides StackDriver Trace support for Node.js applications. [StackD
 
         npm install --save @google/cloud-trace
 
-2. Include and start the library at the *top of the main script of your application*. It's important that the trace agent is the first thing executed so that it can accurately gather data:
+2. Set the GCLOUD_PROJECT environment variable. You can find your Project ID in the [Google Cloud Developers Console][cloud-console], or by running the command `gcloud projects list`. You can ensure this environment variable is set at startup time by placing it in your startup script in `package.json`:
 
-        require('@google/cloud-trace').start({projectId: 'your-project-id'});
+        "scripts": {
+          "start": "GCLOUD_PROJECT=<YOUR_PROJECT_ID> node server.js",
+        },
 
-Your project ID is visible in the [Google Cloud Console Console](https://console.cloud.google.com/project?_ga=1.258049870.576536942.1443543237), it may be something like `particular-future-12345`. If your application is [running on Google Cloud Platform](running-on-google-cloud-platform), you don't need to specify the project ID.
+3. Include and start the library at the *as the very first action in your application*:
+
+        require('@google/cloud-trace').start();
+
+If you use `--require` in your start up command, make sure that the trace agent is --required first.
+If you are running somewhere other than the Google Cloud Platform, see [running elsewhere](#running-elsewhere).
 
 ## Configuration
 
 See [the default configuration](config.js) for a list of possible configuration options. These options can be passed to the agent through the object argument to the start command shown above:
 
-         require('@google/cloud-trace').start({projectId: 'your-project-id', samplingRate: 500});
+         require('@google/cloud-trace').start({samplingRate: 500});
 
 Alternatively, you can provide configuration through a config file. This can be useful if you want to load our module using `--require` on the command line instead of editing your main script. You can start by copying the default config file and modifying it to suit your needs. The `GCLOUD_DIAGNOSTICS_CONFIG` environment variable should point to your configuration file.
 
@@ -48,7 +55,7 @@ If you are using [Google App Engine flexible environment](https://cloud.google.c
 
 ### Google Compute Engine
 
-Your VM instances need to be created with `cloud-platform` scope if created via [gcloud](https://cloud.google.com/sdk) or the 'Allow API access' checkbox selected if created via the [console](https://console.cloud.google.com) (see screenshot).
+Your VM instances need to be created with `cloud-platform` scope if created via [gcloud](https://cloud.google.com/sdk) or the 'Allow API access' checkbox selected if created via the [console][cloud-console] (see screenshot).
 
 ![GCE API](doc/images/gce.png?raw=true)
 
@@ -64,7 +71,7 @@ If your application is running outside of Google Cloud Platform, such as locally
 
 1. You will need to specify your project ID when starting the trace agent.
 
-        require('@google/cloud-trace').start({projectId: 'your-project-id'});
+        GCLOUD_PROJECT=particular-future-12345 node myapp.js
 
 2. You will need to provide service account credentials to your application. The recommended way is via [Application Default Credentials](https://developers.google.com/identity/protocols/application-default-credentials). These can be provisioned by executing the following command:
 
@@ -177,7 +184,7 @@ You can add additional labels using `agent.addTransactionLabel`:
 
 * See [LICENSE](LICENSE)
 
-
+[cloud-console]: https://console.cloud.google.com
 [npm-image]: https://badge.fury.io/js/%40google%2Fcloud-trace.svg
 [npm-url]: https://npmjs.org/package/@google/cloud-trace
 [travis-image]: https://travis-ci.org/GoogleCloudPlatform/cloud-trace-nodejs.svg?branch=master
diff --git a/index.js b/index.js
index 29bafa6ca..5c846edeb 100644
--- a/index.js
+++ b/index.js
@@ -80,8 +80,8 @@ var initConfig = function(projectConfig) {
   if (process.env.hasOwnProperty('GCLOUD_TRACE_DISABLE')) {
     config.enabled = false;
   }
-  if (process.env.hasOwnProperty('GCLOUD_PROJECT_NUM')) {
-    config.projectId = process.env.GCLOUD_PROJECT_NUM;
+  if (process.env.hasOwnProperty('GCLOUD_PROJECT')) {
+    config.projectId = process.env.GCLOUD_PROJECT;
   }
   return config;
 };
diff --git a/test/hooks/common.js b/test/hooks/common.js
index 501b17a56..7a04c6eb1 100644
--- a/test/hooks/common.js
+++ b/test/hooks/common.js
@@ -15,8 +15,8 @@
  */
 'use strict';
 
-if (!process.env.GCLOUD_PROJECT_NUM) {
-  console.log('The GCLOUD_PROJECT_NUM environment variable must be set.');
+if (!process.env.GCLOUD_PROJECT) {
+  console.log('The GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }
 
diff --git a/test/non-interference/express-e2e.js b/test/non-interference/express-e2e.js
index 7b5eb25a8..d0ca930ee 100644
--- a/test/non-interference/express-e2e.js
+++ b/test/non-interference/express-e2e.js
@@ -26,11 +26,11 @@ var semver = require('semver');
 var SUPPORTED_VERSIONS = '<4.x';
 
 if (process.argv.length === 4 && process.argv[2] === '-p') {
-  process.env.GCLOUD_PROJECT_NUM = process.argv[3];
+  process.env.GCLOUD_PROJECT = process.argv[3];
 }
-if (!process.env.GCLOUD_PROJECT_NUM) {
+if (!process.env.GCLOUD_PROJECT) {
   console.log('Project number must be provided with the -p flag or' +
-      ' the GCLOUD_PROJECT_NUM environment variable must be set.');
+      ' the GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }
 if (!semver.satisfies(process.version, SUPPORTED_VERSIONS)) {
diff --git a/test/non-interference/http-e2e.js b/test/non-interference/http-e2e.js
index 0fe9a4737..fa372078b 100644
--- a/test/non-interference/http-e2e.js
+++ b/test/non-interference/http-e2e.js
@@ -25,11 +25,11 @@ var tmp = require('tmp');
 var semver = require('semver');
 
 if (process.argv.length === 4 && process.argv[2] === '-p') {
-  process.env.GCLOUD_PROJECT_NUM = process.argv[3];
+  process.env.GCLOUD_PROJECT = process.argv[3];
 }
-if (!process.env.GCLOUD_PROJECT_NUM) {
+if (!process.env.GCLOUD_PROJECT) {
   console.log('Project number must be provided with the -p flag or' +
-      ' the GCLOUD_PROJECT_NUM environment variable must be set.');
+      ' the GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }
 
diff --git a/test/non-interference/mongo-e2e.js b/test/non-interference/mongo-e2e.js
index 63f67c163..c86a4d11c 100644
--- a/test/non-interference/mongo-e2e.js
+++ b/test/non-interference/mongo-e2e.js
@@ -22,11 +22,11 @@ var path = require('path');
 var tmp = require('tmp');
 
 if (process.argv.length === 4 && process.argv[2] === '-p') {
-  process.env.GCLOUD_PROJECT_NUM = process.argv[3];
+  process.env.GCLOUD_PROJECT = process.argv[3];
 }
-if (!process.env.GCLOUD_PROJECT_NUM) {
+if (!process.env.GCLOUD_PROJECT) {
   console.log('Project number must be provided with the -p flag or' +
-      ' the GCLOUD_PROJECT_NUM environment variable must be set.');
+      ' the GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }
 
@@ -48,7 +48,7 @@ glob('google-cloud-trace-*.tgz', function(err, files) {
   build.on('close', function(code) {
     if (!code) {
       var test = cp.spawn('docker', ['run', '-w', '/mongo', '-t', 'test', 'node',
-          'test/runner.js', '-e', 'GCLOUD_PROJECT_NUM=' + process.env.GCLOUD_PROJECT_NUM,
+          'test/runner.js', '-e', 'GCLOUD_PROJECT=' + process.env.GCLOUD_PROJECT,
           '-t', 'functional']);
       test.stdout.on('data', function(data) { console.log(data.toString()); });
       test.stderr.on('data', function(data) { console.log(data.toString()); });
diff --git a/test/non-interference/restify-e2e.js b/test/non-interference/restify-e2e.js
index 28e2faaec..32da6af84 100644
--- a/test/non-interference/restify-e2e.js
+++ b/test/non-interference/restify-e2e.js
@@ -26,11 +26,11 @@ var semver = require('semver');
 var SUPPORTED_VERSIONS = '<4.x';
 
 if (process.argv.length === 4 && process.argv[2] === '-p') {
-  process.env.GCLOUD_PROJECT_NUM = process.argv[3];
+  process.env.GCLOUD_PROJECT = process.argv[3];
 }
-if (!process.env.GCLOUD_PROJECT_NUM) {
+if (!process.env.GCLOUD_PROJECT) {
   console.log('Project number must be provided with the -p flag or' +
-      ' the GCLOUD_PROJECT_NUM environment variable must be set.');
+      ' the GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }
 if (!semver.satisfies(process.version, SUPPORTED_VERSIONS)) {
diff --git a/test/standalone/test-agent-metadata.js b/test/standalone/test-agent-metadata.js
index c74a4c210..c7b4fa28f 100644
--- a/test/standalone/test-agent-metadata.js
+++ b/test/standalone/test-agent-metadata.js
@@ -23,7 +23,7 @@ var traceLabels = require('../../lib/trace-labels.js');
 
 nock.disableNetConnect();
 
-delete process.env.GCLOUD_PROJECT_NUM;
+delete process.env.GCLOUD_PROJECT;
 
 describe('agent interaction with metadata service', function() {
 
@@ -69,9 +69,9 @@ describe('agent interaction with metadata service', function() {
 
   it('should not query metadata service when env. var. is set', function() {
     nock.disableNetConnect();
-    process.env.GCLOUD_PROJECT_NUM=0;
+    process.env.GCLOUD_PROJECT=0;
     agent.start({logLevel: 0});
-    delete process.env.GCLOUD_PROJECT_NUM;
+    delete process.env.GCLOUD_PROJECT;
   });
 
   it('should attach hostname to spans when provided', function(done) {
diff --git a/test/standalone/test-agent-stopped.js b/test/standalone/test-agent-stopped.js
index e9cf94588..be7d77486 100644
--- a/test/standalone/test-agent-stopped.js
+++ b/test/standalone/test-agent-stopped.js
@@ -19,7 +19,7 @@
 var assert = require('assert');
 var http = require('http');
 
-process.env.GCLOUD_PROJECT_NUM = 0;
+process.env.GCLOUD_PROJECT = 0;
 
 describe('express', function() {
   it('should not break if no project number is found', function(done) {
diff --git a/test/standalone/test-env-project-id.js b/test/standalone/test-env-project-id.js
index 27b82ea10..784525a30 100644
--- a/test/standalone/test-env-project-id.js
+++ b/test/standalone/test-env-project-id.js
@@ -16,13 +16,13 @@
 
 'use strict';
 
-process.env.GCLOUD_PROJECT_NUM = 1729;
+process.env.GCLOUD_PROJECT = 1729;
 
 var assert = require('assert');
 var agent = require('../..');
 
 describe('should respect environment variables', function() {
-  it('should respect GCLOUD_PROJECT_NUM', function() {
+  it('should respect GCLOUD_PROJECT', function() {
     agent.start();
     assert.equal(agent.private_().config_.projectId, 1729);
     agent.stop();
diff --git a/test/standalone/test-hooks-no-project-num.js b/test/standalone/test-hooks-no-project-num.js
index c0da3726a..0c1ebd81b 100644
--- a/test/standalone/test-hooks-no-project-num.js
+++ b/test/standalone/test-hooks-no-project-num.js
@@ -15,7 +15,7 @@
  */
 'use strict';
 
-delete process.env.GCLOUD_PROJECT_NUM;
+delete process.env.GCLOUD_PROJECT;
 
 var assert = require('assert');
 
diff --git a/test/standalone/test-index.js b/test/standalone/test-index.js
index bdcada765..23bf91d0a 100644
--- a/test/standalone/test-index.js
+++ b/test/standalone/test-index.js
@@ -16,8 +16,8 @@
 
 'use strict';
 
-if (!process.env.GCLOUD_PROJECT_NUM) {
-  console.log('The GCLOUD_PROJECT_NUM environment variable must be set.');
+if (!process.env.GCLOUD_PROJECT) {
+  console.log('The GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }
 
diff --git a/test/standalone/test-invalid-project-id.js b/test/standalone/test-invalid-project-id.js
index 782bdcbfc..8d0a2f492 100644
--- a/test/standalone/test-invalid-project-id.js
+++ b/test/standalone/test-invalid-project-id.js
@@ -16,7 +16,7 @@
 
 'use strict';
 
-delete process.env.GCLOUD_PROJECT_NUM;
+delete process.env.GCLOUD_PROJECT;
 
 var assert = require('assert');
 var agent = require('../..');
diff --git a/test/standalone/test-no-self-tracing.js b/test/standalone/test-no-self-tracing.js
index db175d730..02b6d8a45 100644
--- a/test/standalone/test-no-self-tracing.js
+++ b/test/standalone/test-no-self-tracing.js
@@ -29,7 +29,7 @@ nock.disableNetConnect();
 
 describe('test-no-self-tracing', function() {
   it('should not trace metadata queries', function(done) {
-    delete process.env.GCLOUD_PROJECT_NUM;
+    delete process.env.GCLOUD_PROJECT;
     var scope = nock('http://metadata.google.internal')
                 .get('/computeMetadata/v1/instance/hostname').reply(200)
                 .get('/computeMetadata/v1/instance/id').reply(200)
@@ -47,7 +47,7 @@ describe('test-no-self-tracing', function() {
   });
 
   it('should not trace publishes', function(done) {
-    process.env.GCLOUD_PROJECT_NUM = 0;
+    process.env.GCLOUD_PROJECT = 0;
     var metadataScope = nock('http://metadata.google.internal')
                 .get('/computeMetadata/v1/instance/hostname').reply(200)
                 .get('/computeMetadata/v1/instance/id').reply(200);
diff --git a/test/standalone/test-trace-writer.js b/test/standalone/test-trace-writer.js
index 73dd4a9e2..acfe45954 100644
--- a/test/standalone/test-trace-writer.js
+++ b/test/standalone/test-trace-writer.js
@@ -27,7 +27,7 @@ nock.disableNetConnect();
 var uri = 'https://cloudtrace.googleapis.com';
 var path = '/v1/projects/0/traces';
 
-process.env.GCLOUD_PROJECT_NUM = 0;
+process.env.GCLOUD_PROJECT = 0;
 
 var queueSpans = function(n, privateAgent) {
   for (var i = 0; i < n; i++) {
diff --git a/test/test-span-data.js b/test/test-span-data.js
index 74e790759..f5cff43a1 100644
--- a/test/test-span-data.js
+++ b/test/test-span-data.js
@@ -16,8 +16,8 @@
 
 'use strict';
 
-if (!process.env.GCLOUD_PROJECT_NUM) {
-  console.log('The GCLOUD_PROJECT_NUM environment variable must be set.');
+if (!process.env.GCLOUD_PROJECT) {
+  console.log('The GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }
 
diff --git a/test/test-trace-agent.js b/test/test-trace-agent.js
index f79406c9e..861e6555a 100644
--- a/test/test-trace-agent.js
+++ b/test/test-trace-agent.js
@@ -18,8 +18,8 @@
 
  var constants = require('../lib/constants.js');
 
-if (!process.env.GCLOUD_PROJECT_NUM) {
-  console.log('The GCLOUD_PROJECT_NUM environment variable must be set.');
+if (!process.env.GCLOUD_PROJECT) {
+  console.log('The GCLOUD_PROJECT environment variable must be set.');
   process.exit(1);
 }