From 567ed2ea3fa7630975a131948077336a4935105e Mon Sep 17 00:00:00 2001
From: Sarah Third <sarahthird@gmail.com>
Date: Tue, 31 Mar 2026 17:05:45 -0700
Subject: [PATCH] [LEMS-3971/vector-pr4] docs(changeset): Added ability to
 score Vector Interactive Graphs

---
 .changeset/lazy-bats-complain.md              |   5 +
 .../score-interactive-graph.test.ts           | 101 ++++++++++++++++++
 .../score-interactive-graph.ts                |  25 +++++
 3 files changed, 131 insertions(+)
 create mode 100644 .changeset/lazy-bats-complain.md

diff --git a/.changeset/lazy-bats-complain.md b/.changeset/lazy-bats-complain.md
new file mode 100644
index 00000000000..cc90879d13f
--- /dev/null
+++ b/.changeset/lazy-bats-complain.md
@@ -0,0 +1,5 @@
+---
+"@khanacademy/perseus-score": minor
+---
+
+Added ability to score Vector Interactive Graphs
diff --git a/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.test.ts b/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.test.ts
index db32ac5c7d3..3e9cdbade0a 100644
--- a/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.test.ts
+++ b/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.test.ts
@@ -932,3 +932,104 @@ describe("InteractiveGraph scoring on a tangent question", () => {
         expect(result).toHaveBeenAnsweredCorrectly();
     });
 });
+
+const vectorRubric: PerseusInteractiveGraphRubric = {
+    graph: {type: "vector"},
+    correct: {
+        type: "vector",
+        coords: [
+            [0, 0],
+            [3, 4],
+        ],
+    },
+};
+
+describe("InteractiveGraph scoring on a vector question", () => {
+    it("marks the answer invalid if guess is undefined", () => {
+        // Arrange, Act
+        const result = scoreInteractiveGraph(undefined, vectorRubric);
+
+        // Assert
+        expect(result).toHaveInvalidInput();
+    });
+
+    it("marks the answer invalid if coords are missing", () => {
+        // Arrange
+        const guess: PerseusGraphType = {type: "vector"};
+
+        // Act
+        const result = scoreInteractiveGraph(guess, vectorRubric);
+
+        // Assert
+        expect(result).toHaveInvalidInput();
+    });
+
+    it("marks a correct answer as correct", () => {
+        // Arrange
+        const guess: PerseusGraphType = {
+            type: "vector",
+            coords: [
+                [0, 0],
+                [3, 4],
+            ],
+        };
+
+        // Act
+        const result = scoreInteractiveGraph(guess, vectorRubric);
+
+        // Assert
+        expect(result).toHaveBeenAnsweredCorrectly();
+    });
+
+    it("marks a wrong tail as incorrect", () => {
+        // Arrange — correct tip but wrong tail
+        const guess: PerseusGraphType = {
+            type: "vector",
+            coords: [
+                [1, 1],
+                [3, 4],
+            ],
+        };
+
+        // Act
+        const result = scoreInteractiveGraph(guess, vectorRubric);
+
+        // Assert
+        expect(result).toHaveBeenAnsweredIncorrectly();
+    });
+
+    it("marks a wrong tip as incorrect", () => {
+        // Arrange — correct tail but wrong tip
+        const guess: PerseusGraphType = {
+            type: "vector",
+            coords: [
+                [0, 0],
+                [4, 5],
+            ],
+        };
+
+        // Act
+        const result = scoreInteractiveGraph(guess, vectorRubric);
+
+        // Assert
+        expect(result).toHaveBeenAnsweredIncorrectly();
+    });
+
+    it("marks swapped tail and tip as incorrect", () => {
+        // Arrange — coords are reversed (tip at tail position, tail at tip)
+        // Unlike ray, vector scoring is order-sensitive
+        const guess: PerseusGraphType = {
+            type: "vector",
+            coords: [
+                [3, 4],
+                [0, 0],
+            ],
+        };
+
+        // Act
+        const result = scoreInteractiveGraph(guess, vectorRubric);
+
+        // Assert
+        expect(result).toHaveBeenAnsweredIncorrectly();
+    });
+});
diff --git a/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.ts b/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.ts
index 33fb1f152f7..df7db01d237 100644
--- a/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.ts
+++ b/packages/perseus-score/src/widgets/interactive-graph/score-interactive-graph.ts
@@ -395,6 +395,31 @@ function scoreInteractiveGraph(
                     message: null,
                 };
             }
+        } else if (
+            userInput.type === "vector" &&
+            rubric.correct.type === "vector" &&
+            userInput.coords != null &&
+            rubric.correct.coords != null
+        ) {
+            // Vector scoring: both tail and tip must match exactly.
+            // Order matters — coords[0] is tail, coords[1] is tip.
+            if (
+                approximateDeepEqual(
+                    userInput.coords[0],
+                    rubric.correct.coords[0],
+                ) &&
+                approximateDeepEqual(
+                    userInput.coords[1],
+                    rubric.correct.coords[1],
+                )
+            ) {
+                return {
+                    type: "points",
+                    earned: 1,
+                    total: 1,
+                    message: null,
+                };
+            }
         }
     }