diff --git a/src/analysis/fallbackDeclaration.js b/src/analysis/fallbackDeclaration.js
index bea55ac..717960e 100644
--- a/src/analysis/fallbackDeclaration.js
+++ b/src/analysis/fallbackDeclaration.js
@@ -23,6 +23,8 @@ export const fallbackEdgeType: EdgeType = Object.freeze({
   defaultForwardWeight: 1,
   defaultBackwardWeight: 1,
   prefix: EdgeAddress.empty,
+  description:
+    "The fallback EdgeType for edges which don't have any other type",
 });
 
 export const fallbackDeclaration: PluginDeclaration = Object.freeze({
diff --git a/src/analysis/types.js b/src/analysis/types.js
index 82ed4bd..3e95978 100644
--- a/src/analysis/types.js
+++ b/src/analysis/types.js
@@ -96,4 +96,7 @@ export type EdgeType = {|
   // of this EdgeType. A given edge `e` is a member of the type `t` if
   // `EdgeAddress.hasPrefix(e.address, t.prefix) == true`
   +prefix: EdgeAddressT,
+  // The `description` property should be a human-readable string that makes
+  // it clear to a user what each EdgeType does
+  +description: string,
 |};
diff --git a/src/explorer/pagerankTable/Aggregation.test.js b/src/explorer/pagerankTable/Aggregation.test.js
index 7aa97ef..0cfaca3 100644
--- a/src/explorer/pagerankTable/Aggregation.test.js
+++ b/src/explorer/pagerankTable/Aggregation.test.js
@@ -157,6 +157,7 @@ describe("explorer/pagerankTable/Aggregation", () => {
       defaultForwardWeight: 1,
       defaultBackwardWeight: 1,
       prefix: EdgeAddress.fromParts(["look", "like"]),
+      description: "TODO: Add a description for this EdgeType",
     };
     function aggView(aggregation: FlatAggregation) {
       const el = shallow(<AggregationView aggregation={aggregation} />);
diff --git a/src/explorer/pagerankTable/aggregate.test.js b/src/explorer/pagerankTable/aggregate.test.js
index f15f198..c14f3e6 100644
--- a/src/explorer/pagerankTable/aggregate.test.js
+++ b/src/explorer/pagerankTable/aggregate.test.js
@@ -66,6 +66,7 @@ describe("explorer/pagerankTable/aggregate", () => {
         defaultForwardWeight: 1,
         defaultBackwardWeight: 1,
         prefix: EdgeAddress.fromParts(["foo"]),
+        description: "TODO: Add a description for this EdgeType",
       },
       bar: {
         forwardName: "bars",
@@ -73,6 +74,7 @@ describe("explorer/pagerankTable/aggregate", () => {
         defaultForwardWeight: 1,
         defaultBackwardWeight: 1,
         prefix: EdgeAddress.fromParts(["bar"]),
+        description: "TODO: Add a description for this EdgeType",
       },
       empty: {
         forwardName: "empty",
@@ -80,6 +82,7 @@ describe("explorer/pagerankTable/aggregate", () => {
         defaultForwardWeight: 1,
         defaultBackwardWeight: 1,
         prefix: EdgeAddress.empty,
+        description: "TODO: Add a description for this EdgeType",
       },
     };
     const edgeTypesArray = [edgeTypes.foo, edgeTypes.bar];
diff --git a/src/explorer/weights/EdgeTypeConfig.js b/src/explorer/weights/EdgeTypeConfig.js
index 1490afb..c2d36b4 100644
--- a/src/explorer/weights/EdgeTypeConfig.js
+++ b/src/explorer/weights/EdgeTypeConfig.js
@@ -15,6 +15,7 @@ export class EdgeTypeConfig extends React.Component<{
         <EdgeWeightSlider
           name={this.props.weightedType.type.backwardName}
           weight={this.props.weightedType.forwardWeight}
+          description={this.props.weightedType.type.description}
           onChange={(forwardWeight) => {
             this.props.onChange({
               ...this.props.weightedType,
@@ -25,6 +26,7 @@ export class EdgeTypeConfig extends React.Component<{
         <EdgeWeightSlider
           name={this.props.weightedType.type.forwardName}
           weight={this.props.weightedType.backwardWeight}
+          description={this.props.weightedType.type.description}
           onChange={(backwardWeight) => {
             this.props.onChange({
               ...this.props.weightedType,
@@ -57,6 +59,7 @@ export class EdgeWeightSlider extends React.Component<WeightSliderProps> {
       <WeightSlider
         name={modifiedName}
         weight={this.props.weight}
+        description={this.props.description}
         onChange={this.props.onChange}
       />
     );
diff --git a/src/explorer/weights/EdgeTypeConfig.test.js b/src/explorer/weights/EdgeTypeConfig.test.js
index f9e5401..210f45d 100644
--- a/src/explorer/weights/EdgeTypeConfig.test.js
+++ b/src/explorer/weights/EdgeTypeConfig.test.js
@@ -54,7 +54,12 @@ describe("explorer/weights/EdgeTypeConfig", () => {
     function example() {
       const onChange = jest.fn();
       const element = shallow(
-        <EdgeWeightSlider weight={3} name="foo" onChange={onChange} />
+        <EdgeWeightSlider
+          weight={3}
+          name="foo"
+          description="Description for test slider"
+          onChange={onChange}
+        />
       );
       const weightSlider = element.find(WeightSlider);
       return {element, onChange, weightSlider};
diff --git a/src/explorer/weights/NodeTypeConfig.js b/src/explorer/weights/NodeTypeConfig.js
index 4ebba5c..3571799 100644
--- a/src/explorer/weights/NodeTypeConfig.js
+++ b/src/explorer/weights/NodeTypeConfig.js
@@ -13,6 +13,7 @@ export class NodeTypeConfig extends React.Component<{
       <WeightSlider
         name={this.props.weightedType.type.name}
         weight={this.props.weightedType.weight}
+        description={this.props.weightedType.type.description}
         onChange={(weight) => {
           this.props.onChange({
             ...this.props.weightedType,
diff --git a/src/explorer/weights/WeightSlider.js b/src/explorer/weights/WeightSlider.js
index 289cb18..b631024 100644
--- a/src/explorer/weights/WeightSlider.js
+++ b/src/explorer/weights/WeightSlider.js
@@ -6,11 +6,12 @@ export type Props = {|
   +weight: number,
   +name: React$Node,
   +onChange: (number) => void,
+  +description: string,
 |};
 export class WeightSlider extends React.Component<Props> {
   render() {
     return (
-      <label style={{display: "flex"}}>
+      <label style={{display: "flex"}} title={this.props.description}>
         <span style={{flexGrow: 1}}>{this.props.name}</span>
         <input
           type="range"
diff --git a/src/explorer/weights/WeightSlider.test.js b/src/explorer/weights/WeightSlider.test.js
index a44e36b..6ef4d1f 100644
--- a/src/explorer/weights/WeightSlider.test.js
+++ b/src/explorer/weights/WeightSlider.test.js
@@ -12,7 +12,12 @@ describe("explorer/weights/WeightSlider", () => {
     function example() {
       const onChange = jest.fn();
       const element = shallow(
-        <WeightSlider weight={3} name="foo" onChange={onChange} />
+        <WeightSlider
+          weight={3}
+          name="foo"
+          description="Description for test slider"
+          onChange={onChange}
+        />
       );
       return {element, onChange};
     }
diff --git a/src/plugins/demo/declaration.js b/src/plugins/demo/declaration.js
index 6b9bbac..8517b45 100644
--- a/src/plugins/demo/declaration.js
+++ b/src/plugins/demo/declaration.js
@@ -28,6 +28,7 @@ export const assemblesEdgeType: EdgeType = Object.freeze({
   backwardName: "is assembled by",
   defaultBackwardWeight: 2 ** -2,
   prefix: EdgeAddress.fromParts(["factorio", "assembles"]),
+  description: "TODO: Add a description for this EdgeType",
 });
 
 export const transportsEdgeType: EdgeType = Object.freeze({
@@ -36,6 +37,7 @@ export const transportsEdgeType: EdgeType = Object.freeze({
   backwardName: "is transported by",
   defaultBackwardWeight: 2 ** -1,
   prefix: EdgeAddress.fromParts(["factorio", "transports"]),
+  description: "TODO: Add a description for this EdgeType",
 });
 
 export const declaration: PluginDeclaration = Object.freeze({
diff --git a/src/plugins/git/declaration.js b/src/plugins/git/declaration.js
index 66c588a..abdd106 100644
--- a/src/plugins/git/declaration.js
+++ b/src/plugins/git/declaration.js
@@ -19,6 +19,7 @@ const hasParentEdgeType = Object.freeze({
   prefix: E.Prefix.hasParent,
   defaultForwardWeight: 1,
   defaultBackwardWeight: 1,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const nodeTypes = Object.freeze([commitNodeType]);
diff --git a/src/plugins/github/declaration.js b/src/plugins/github/declaration.js
index 6794ee3..9c3f639 100644
--- a/src/plugins/github/declaration.js
+++ b/src/plugins/github/declaration.js
@@ -76,6 +76,7 @@ const authorsEdgeType = Object.freeze({
   defaultForwardWeight: 1 / 2,
   defaultBackwardWeight: 1,
   prefix: E.Prefix.authors,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const hasParentEdgeType = Object.freeze({
@@ -84,6 +85,7 @@ const hasParentEdgeType = Object.freeze({
   defaultForwardWeight: 1,
   defaultBackwardWeight: 1 / 4,
   prefix: E.Prefix.hasParent,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const mergedAsEdgeType = Object.freeze({
@@ -92,6 +94,7 @@ const mergedAsEdgeType = Object.freeze({
   defaultForwardWeight: 1 / 2,
   defaultBackwardWeight: 1,
   prefix: E.Prefix.mergedAs,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const referencesEdgeType = Object.freeze({
@@ -100,6 +103,7 @@ const referencesEdgeType = Object.freeze({
   defaultForwardWeight: 1,
   defaultBackwardWeight: 1 / 16,
   prefix: E.Prefix.references,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const mentionsAuthorEdgeType = Object.freeze({
@@ -109,6 +113,7 @@ const mentionsAuthorEdgeType = Object.freeze({
   // TODO(#811): Probably change this to 0
   defaultBackwardWeight: 1 / 32,
   prefix: E.Prefix.mentionsAuthor,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const reactsHeartEdgeType = Object.freeze({
@@ -118,6 +123,7 @@ const reactsHeartEdgeType = Object.freeze({
   // TODO(#811): Probably change this to 0
   defaultBackwardWeight: 1 / 32,
   prefix: E.Prefix.reactsHeart,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const reactsThumbsUpEdgeType = Object.freeze({
@@ -127,6 +133,7 @@ const reactsThumbsUpEdgeType = Object.freeze({
   // TODO(#811): Probably change this to 0
   defaultBackwardWeight: 1 / 32,
   prefix: E.Prefix.reactsThumbsUp,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const reactsHoorayEdgeType = Object.freeze({
@@ -136,6 +143,7 @@ const reactsHoorayEdgeType = Object.freeze({
   // TODO(#811): Probably change this to 0
   defaultBackwardWeight: 1 / 32,
   prefix: E.Prefix.reactsHooray,
+  description: "TODO: Add a description for this EdgeType",
 });
 
 const reactsRocketEdgeType = Object.freeze({