diff --git a/buildcfg/jsdoc/externs/conf.json b/buildcfg/jsdoc/externs/conf.json
deleted file mode 100644
index 0371382163..0000000000
--- a/buildcfg/jsdoc/externs/conf.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-    "opts": {
-        "recurse": true,
-        "template": "buildcfg/jsdoc/externs"
-    },
-    "tags": {
-        "allowUnknownTags": true
-    },
-    "source": {
-        "includePattern": "\\.js$"
-    },
-    "plugins": [
-        "buildcfg/jsdoc/api-plugin",
-        "buildcfg/jsdoc/define-plugin"
-    ]
-}
diff --git a/buildcfg/jsdoc/externs/publish.js b/buildcfg/jsdoc/externs/publish.js
deleted file mode 100644
index f050be590c..0000000000
--- a/buildcfg/jsdoc/externs/publish.js
+++ /dev/null
@@ -1,130 +0,0 @@
-/**
- * @fileoverview Generates a closure compiler externs file for exportable
- * symbols (those with an api tag) and boolean defines (with a define tag and a
- * default value).
- */
-var assert = require('assert');
-var fs = require('fs');
-var path = require('path');
-
-
-/**
- * Publish hook for the JSDoc template.  Writes to stdout.
- * @param {function} data The root of the Taffy DB containing doclet records.
- * @param {Object} opts Options.
- */
-exports.publish = function(data, opts) {
-
-  // get all doclets with the "api" property or define (excluding enums,
-  // typedefs and events)
-  var docs = data(
-      [{define: {isObject: true}}, {api: {isString: true}}],
-      {isEnum: {'!is': true}},
-      {kind: {'!is': 'typedef'}},
-      {kind: {'!is': 'event'}}).get();
-
-  // get symbols data, filter out those that are members of private classes
-  var output = [];
-  var namespaces = {};
-  var constructors = {};
-  docs.filter(function(doc) {
-    var include = true;
-    var constructor = doc.memberof;
-    if (constructor && constructor.substr(-1) === '_') {
-      assert.strictEqual(doc.inherited, true,
-          'Unexpected export on private class: ' + doc.longname);
-      include = false;
-    }
-    return include;
-  }).forEach(function(doc) {
-
-    var parts = doc.longname.split('#')[0].split('.');
-    parts.pop();
-    var namespace = [];
-    parts.forEach(function(part) {
-      namespace.push(part);
-      var partialNamespace = namespace.join('.');
-      if (!(partialNamespace in namespaces)) {
-        namespaces[partialNamespace] = true;
-        output.push('/**');
-        output.push(' * @type {Object}');
-        output.push(' */');
-        output.push(
-            (namespace.length == 1 ? 'var ' : '') + partialNamespace + ';');
-        output.push('');
-      }
-    });
-
-    var signature = doc.longname;
-    if (signature.indexOf('#') > 0) {
-      signature = doc.longname.replace('#', '.prototype.');
-      var constructor = doc.longname.split('#')[0];
-      if (!(constructor in constructors)) {
-        constructors[constructor] = true;
-        output.push('/**');
-        output.push(' * @constructor');
-        output.push(' */');
-        output.push(constructor + ' = function() {}');
-        output.push('');
-      }
-    }
-
-    output.push('/**');
-    if (doc.define) {
-      output.push(' * @define');
-      output.push(' * @type {boolean}');
-      output.push(' */');
-      output.push(doc.longname + ';');
-    } else {
-      if (doc.kind == 'class') {
-        output.push(' * @constructor');
-      }
-      if (doc.type) {
-        var types = [];
-        doc.type.names.forEach(function(name) {
-          types.push(name);
-        });
-        output.push(' * @type {' + types.join('|') + '}');
-      }
-      var args = [];
-      if (doc.params) {
-        doc.params.forEach(function(param) {
-          args.push(param.name);
-          var names = [];
-          param.type.names.forEach(function(name) {
-            names.push(name);
-          });
-          output.push(' * @param {' +
-              (param.variable ? '...' : '') +
-              names.join('|') +
-              (param.optional ? '=' : '') +
-              '} ' + param.name);
-        });
-      }
-      if (doc.returns) {
-        var returnTypes = [];
-        doc.returns[0].type.names.forEach(function(name) {
-          returnTypes.push(name);
-        });
-        output.push(' * @return {' + returnTypes.join('|') + '}');
-      }
-      if (doc.tags) {
-        doc.tags.forEach(function(tag) {
-          if (tag.title == 'template') {
-            output.push(' * @' + tag.title + ' ' + tag.value);
-          }
-        });
-      }
-      output.push(' */');
-      if (doc.kind == 'function' || doc.kind == 'class') {
-        output.push(signature + ' = function(' + args.join(', ') + ') {};');
-      } else {
-        output.push(signature);
-      }
-    }
-    output.push('');
-  });
-
-  process.stdout.write(output.join('\n'));
-
-};
diff --git a/buildcfg/jsdoc/api-plugin.js b/buildcfg/jsdoc/info/api-plugin.js
similarity index 100%
rename from buildcfg/jsdoc/api-plugin.js
rename to buildcfg/jsdoc/info/api-plugin.js
diff --git a/buildcfg/jsdoc/info/conf.json b/buildcfg/jsdoc/info/conf.json
index 3d2c6c6e53..c66f3993ab 100644
--- a/buildcfg/jsdoc/info/conf.json
+++ b/buildcfg/jsdoc/info/conf.json
@@ -10,7 +10,7 @@
         "includePattern": "\\.js$"
     },
     "plugins": [
-        "buildcfg/jsdoc/api-plugin",
-        "buildcfg/jsdoc/define-plugin"
+        "buildcfg/jsdoc/info/api-plugin",
+        "buildcfg/jsdoc/info/define-plugin"
     ]
 }
diff --git a/buildcfg/jsdoc/define-plugin.js b/buildcfg/jsdoc/info/define-plugin.js
similarity index 100%
rename from buildcfg/jsdoc/define-plugin.js
rename to buildcfg/jsdoc/info/define-plugin.js
diff --git a/buildcfg/jsdoc/info/publish.js b/buildcfg/jsdoc/info/publish.js
index 8badcbf934..1a6e6113b9 100644
--- a/buildcfg/jsdoc/info/publish.js
+++ b/buildcfg/jsdoc/info/publish.js
@@ -44,12 +44,58 @@ exports.publish = function(data, opts) {
         default: doc.define.default
       });
     } else {
-      symbols.push({
+      var types;
+      var symbol = {
         name: doc.longname,
         kind: doc.kind,
         description: doc.classdesc || doc.description,
         path: path.join(doc.meta.path, doc.meta.filename)
-      });
+      };
+      if (doc.type) {
+        var types = [];
+        doc.type.names.forEach(function(name) {
+          types.push(name);
+        });
+        symbol.types = types;
+      }
+      if (doc.params) {
+        var params = [];
+        doc.params.forEach(function(param) {
+          var paramInfo = {
+            name: param.name
+          };
+          params.push(paramInfo);
+          var types = [];
+          param.type.names.forEach(function(name) {
+            types.push(name);
+          });
+          paramInfo.types = types;
+          if (typeof param.variable == 'boolean') {
+            paramInfo.variable = param.variable;
+          }
+          if (typeof param.optional == 'boolean') {
+            paramInfo.optional = param.optional;
+          }
+        });
+        symbol.params = params;
+      }
+      if (doc.returns) {
+        var returns = [];
+        doc.returns[0].type.names.forEach(function(name) {
+          returns.push(name);
+        });
+        symbol.returns = returns;
+      }
+      if (doc.tags) {
+        doc.tags.every(function(tag) {
+          if (tag.title == 'template') {
+            symbol.template = tag.value;
+            return false;
+          }
+          return true;
+        });
+      }
+      symbols.push(symbol);
     }
   });
 
diff --git a/tasks/generate-externs.js b/tasks/generate-externs.js
index 4498990432..7eaec497bb 100644
--- a/tasks/generate-externs.js
+++ b/tasks/generate-externs.js
@@ -1,157 +1,160 @@
 var fs = require('fs');
 var path = require('path');
-var spawn = require('child_process').spawn;
 
 var async = require('async');
 var fse = require('fs-extra');
-var walk = require('walk').walk;
+var nomnom = require('nomnom');
+
+var generateInfo = require('./generate-info');
 
-var sourceDir = path.join(__dirname, '..', 'src');
 var olxPath = path.join(__dirname, '..', 'externs', 'olx.js');
-var externsPath = path.join(__dirname, '..', 'build', 'ol-externs.js');
-var jsdoc = path.join(__dirname, '..', 'node_modules', '.bin', 'jsdoc');
-var jsdocConfig = path.join(
-    __dirname, '..', 'buildcfg', 'jsdoc', 'externs', 'conf.json');
 
 
 /**
- * Get the mtime of the externs file.
- * @param {function(Error, Date)} callback Callback called with any
- *     error and the mtime of the externs file (zero date if it doesn't exist).
+ * Read the symbols from info file.
+ * @param {funciton(Error, Array.<string>, Array.<Object>)} callback Called
+ *     with the patterns and symbols (or any error).
  */
-function getExternsTime(callback) {
-  fs.stat(externsPath, function(err, stats) {
+function getSymbols(callback) {
+  generateInfo(function(err) {
     if (err) {
-      if (err.code === 'ENOENT') {
-        callback(null, new Date(0));
+      callback(new Error('Trouble generating info: ' + err.message));
+      return;
+    }
+    var symbols = require('../build/info.json').symbols;
+    callback(null, symbols);
+  });
+}
+
+
+/**
+ * Generate externs code given a list symbols.
+ * @param {Array.<Object>} symbols List of symbols.
+ * @param {string|undefined} namespace Target object for exported symbols.
+ * @return {string} Export code.
+ */
+function generateExterns(symbols) {
+  var lines = [];
+  var namespaces = {};
+  var constructors = {};
+
+  symbols.forEach(function(symbol) {
+    var parts = symbol.name.split('#')[0].split('.');
+    parts.pop();
+    var namespace = [];
+    parts.forEach(function(part) {
+      namespace.push(part);
+      var partialNamespace = namespace.join('.');
+      if (!(partialNamespace in namespaces)) {
+        namespaces[partialNamespace] = true;
+        lines.push('/**');
+        lines.push(' * @type {Object}');
+        lines.push(' */');
+        lines.push(
+            (namespace.length == 1 ? 'var ' : '') + partialNamespace + ';');
+        lines.push('\n');
+      }
+    });
+
+    var name = symbol.name;
+    if (name.indexOf('#') > 0) {
+      name = symbol.name.replace('#', '.prototype.');
+      var constructor = symbol.name.split('#')[0];
+      if (!(constructor in constructors)) {
+        constructors[constructor] = true;
+        lines.push('/**');
+        lines.push(' * @constructor');
+        lines.push(' */');
+        lines.push(constructor + ' = function() {};');
+        lines.push('\n');
+      }
+    }
+
+    lines.push('/**');
+    if ('default' in symbol) {
+      lines.push(' * @define');
+      lines.push(' * @type {boolean}');
+      lines.push(' */');
+      lines.push(symbol.name + ';');
+    } else {
+      if (symbol.kind == 'class') {
+        lines.push(' * @constructor');
+      }
+      if (symbol.types) {
+        lines.push(' * @type {' + symbol.types.join('|') + '}');
+      }
+      var args = [];
+      if (symbol.params) {
+        symbol.params.forEach(function(param) {
+          args.push(param.name);
+          lines.push(' * @param {' +
+              (param.variable ? '...' : '') +
+              param.types.join('|') +
+              (param.optional ? '=' : '') +
+              '} ' + param.name);
+        });
+      }
+      if (symbol.returns) {
+        lines.push(' * @return {' + symbol.returns.join('|') + '}');
+      }
+      if (symbol.template) {
+        lines.push(' * @template ' + symbol.template);
+      }
+      lines.push(' */');
+      if (symbol.kind == 'function' || symbol.kind == 'class') {
+        lines.push(name + ' = function(' + args.join(', ') + ') {};');
       } else {
-        callback(err);
-      }
-    } else {
-      callback(null, stats.mtime);
-    }
-  });
-}
-
-
-/**
- * Generate a list of all .js paths in the source directory if any are newer
- * than the provided date.
- * @param {Date} date Modification time of externs file.
- * @param {function(Error, Array.<string>)} callback Called with any
- *     error and the array of source paths (empty if none newer).
- */
-function getNewer(date, callback) {
-  var paths = [];
-  var newer = false;
-
-  var walker = walk(sourceDir);
-  walker.on('file', function(root, stats, next) {
-    var sourcePath = path.join(root, stats.name);
-    if (/\.js$/.test(sourcePath)) {
-      paths.push(sourcePath);
-      if (stats.mtime > date) {
-        newer = true;
+        lines.push(name + ';');
       }
     }
-    next();
-  });
-  walker.on('errors', function() {
-    callback(new Error('Trouble walking ' + sourceDir));
-  });
-  walker.on('end', function() {
-    callback(null, newer ? paths : []);
+    lines.push('\n');
   });
+  
+  return lines.join('\n');
 }
 
 
 /**
- * Spawn JSDoc.
- * @param {Array.<string>} paths Paths to source files.
- * @param {function(Error, string)} callback Callback called with any error and
- *     the JSDoc output (new metadata).  If provided with an empty list of paths
- *     the callback will be called with null.
- */
-function spawnJSDoc(paths, callback) {
-  if (paths.length === 0) {
-    process.nextTick(function() {
-      callback(null, null);
-    });
-    return;
-  }
-
-  var output = '';
-  var errors = '';
-  var cwd = path.join(__dirname, '..');
-  var child = spawn(jsdoc, ['-c', jsdocConfig].concat(paths), {cwd: cwd});
-
-  child.stdout.on('data', function(data) {
-    output += String(data);
-  });
-
-  child.stderr.on('data', function(data) {
-    errors += String(data);
-  });
-
-  child.on('exit', function(code) {
-    if (code) {
-      callback(new Error(errors || 'JSDoc failed with no output'));
-    } else {
-      callback(null, output);
-    }
-  });
-}
-
-
-/**
- * Write externs file consisting of externs/olx.js and the JSDoc generated
- *     externs.
- * @param {Object} externs JSDoc generated externs.
- * @param {function(Error)} callback Callback.
- */
-function writeExterns(externs, callback) {
-  if (externs) {
-    var olx;
-    try {
-      olx = fs.readFileSync(olxPath, {encoding: 'utf-8'})
-          .replace(/ \* @api ?(.*)?(\r\n|\n|\r)/gm, '');
-    } catch(e) {
-      process.nextTick(function() {
-        callback(null);
-      });
-    }
-    fse.outputFile(externsPath, olx + '\n\n' + externs, callback);
-  } else {
-    process.nextTick(function() {
-      callback(null);
-    });
-  }
-}
-
-
-/**
- * Determine if source files have been changed, run JSDoc and write updated
- * externs if there are any changes.
+ * Generate the exports code.
  *
- * @param {function(Error)} callback Called when the externs file has been
- *     written (or an error occurs).
+ * @param {function(Error, string)} callback Called with the exports code or any
+ *     error generating it.
  */
 function main(callback) {
   async.waterfall([
-    getExternsTime,
-    getNewer,
-    spawnJSDoc,
-    writeExterns
+    getSymbols,
+    function(symbols, done) {
+      var code, err;
+      try {
+        var olx = fs.readFileSync(olxPath, {encoding: 'utf-8'})
+            .replace(/ \* @api ?(.*)?(\r\n|\n|\r)/gm, '');
+        code = olx + '\n\n' + generateExterns(symbols);
+      } catch (e) {
+        err = e;
+      }
+      done(err, code);
+    }
   ], callback);
 }
 
 
 /**
- * If running this module directly, read the config file and call the main
- * function.
+ * If running this module directly, read the config file, call the main
+ * function, and write the output file.
  */
 if (require.main === module) {
-  main(function(err) {
+  var options = nomnom.options({
+    output: {
+      position: 0,
+      required: true,
+      help: 'Output path for the generated externs file.'
+    }
+  }).parse();
+
+  async.waterfall([
+    main,
+    fse.outputFile.bind(fse, options.output)
+  ], function(err) {
     if (err) {
       console.error(err.message);
       process.exit(1);
diff --git a/tasks/readme.md b/tasks/readme.md
index 1e5826242e..ad3fff9f8c 100644
--- a/tasks/readme.md
+++ b/tasks/readme.md
@@ -91,7 +91,10 @@ Called internally to generate a `build/exports.js` file optionally with a limite
 
 ## `generate-externs.js`
 
-Can be called to generate a Closure externs file for the full OpenLayers 3 API. The externs file will be placed as `ol-externs.js` in the `build/` directory.
+Can be called to generate a Closure externs file for the full OpenLayers 3 API.
+See the `--help` option for more detail.
+
+    node tasks/generate-externs.js --help
 
 This is useful for projects that use the Closure Compiler to build, but want to use OpenLayers 3 as external library rather than building together with OpenLayers 3.