diff --git a/main.go b/main.go
index 81d9c34..db31471 100644
--- a/main.go
+++ b/main.go
@@ -54,6 +54,7 @@ func main() {
 	registerSearchFlashcard(mcpServer, searchEngine)
 	registerUpdateFlashcard(mcpServer, sqliteStore, searchEngine, logger)
 	registerDeleteFlashcard(mcpServer, sqliteStore, searchEngine, logger)
+	registerVoteFlashcard(mcpServer, sqliteStore, logger)
 
 	streamableServer := server.NewStreamableHTTPServer(mcpServer)
 
@@ -334,6 +335,92 @@ func handleDeleteFlashcard(sqlite *sqliteStore, engine SearchEngine, logger *zap
 	}
 }
 
+func registerVoteFlashcard(mcpServer *server.MCPServer, sqlite *sqliteStore, logger *zap.Logger) {
+	mcpServer.AddTool(
+		mcp.NewTool("vote_flashcard",
+			mcp.WithDescription("Vote on a flashcard. Rate it from -3 (worst) to 3 (best). Requires detailed context about who is voting and why."),
+			mcp.WithNumber("public_id",
+				mcp.Required(),
+				mcp.Description("Public identifier of the flashcard to vote on"),
+			),
+			mcp.WithNumber("value",
+				mcp.Required(),
+				mcp.Description("Vote value from -3 to 3"),
+			),
+			mcp.WithString("user",
+				mcp.Required(),
+				mcp.Description("Who is voting"),
+			),
+			mcp.WithString("repo",
+				mcp.Required(),
+				mcp.Description("Repository context for the vote"),
+			),
+			mcp.WithString("message",
+				mcp.Required(),
+				mcp.Description("Justification or context for the vote"),
+			),
+		),
+		handleVoteFlashcard(sqlite, logger),
+	)
+}
+
+func handleVoteFlashcard(sqlite *sqliteStore, logger *zap.Logger) server.ToolHandlerFunc {
+	return func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+		args, ok := request.Params.Arguments.(map[string]any)
+		if !ok {
+			return mcp.NewToolResultError("invalid arguments"), nil
+		}
+
+		publicID := parseInt64(args["public_id"])
+		if publicID == 0 {
+			return mcp.NewToolResultError("public_id is required and must be a positive integer"), nil
+		}
+
+		value := int(parseInt64(args["value"]))
+		if value < -3 || value > 3 {
+			return mcp.NewToolResultError("value must be between -3 and 3"), nil
+		}
+
+		user := parseOptionalString(args["user"])
+		if user == "" {
+			return mcp.NewToolResultError("user is required"), nil
+		}
+
+		repo := parseOptionalString(args["repo"])
+		if repo == "" {
+			return mcp.NewToolResultError("repo is required"), nil
+		}
+
+		message := parseOptionalString(args["message"])
+		if message == "" {
+			return mcp.NewToolResultError("message is required"), nil
+		}
+
+		latest, err := sqlite.getLatestByPublicID(ctx, publicID)
+		if err != nil {
+			return mcp.NewToolResultError(fmt.Sprintf("failed to query: %v", err)), nil
+		}
+		if latest == nil {
+			return mcp.NewToolResultError(fmt.Sprintf("no flashcard found with public_id %d", publicID)), nil
+		}
+		if latest.DeleteTimestamp != "" {
+			return mcp.NewToolResultError(fmt.Sprintf("flashcard %d is deleted", publicID)), nil
+		}
+
+		v, err := sqlite.saveVote(ctx, latest.ID, value, user, repo, message)
+		if err != nil {
+			return mcp.NewToolResultError(fmt.Sprintf("failed to save vote: %v", err)), nil
+		}
+
+		output, err := json.MarshalIndent(v, "", "  ")
+		if err != nil {
+			return mcp.NewToolResultError(fmt.Sprintf("failed to marshal: %v", err)), nil
+		}
+
+		return mcp.NewToolResultText(string(output)), nil
+	}
+}
+
 func handleStoreFlashcard(sqlite *sqliteStore, engine SearchEngine, logger *zap.Logger) server.ToolHandlerFunc {
 	return func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
 		args, ok := request.Params.Arguments.(map[string]any)
diff --git a/migrations/000003_add_vote.sql b/migrations/000003_add_vote.sql
new file mode 100644
index 0000000..531ff77
--- /dev/null
+++ b/migrations/000003_add_vote.sql
@@ -0,0 +1,14 @@
+-- +goose Up
+CREATE TABLE IF NOT EXISTS vote (
+    _id INTEGER PRIMARY KEY,
+    flashcard_id INTEGER NOT NULL REFERENCES flashcard(_id),
+    value INTEGER NOT NULL CHECK(value >= -3 AND value <= 3),
+    "user" TEXT NOT NULL,
+    repo TEXT NOT NULL,
+    message TEXT NOT NULL,
+    created TEXT NOT NULL DEFAULT (datetime('now')),
+    UNIQUE(flashcard_id, "user", repo)
+);
+
+-- +goose Down
+DROP TABLE IF EXISTS vote;
diff --git a/sqlite.go b/sqlite.go
index 2093965..9f680a9 100644
--- a/sqlite.go
+++ b/sqlite.go
@@ -43,6 +43,11 @@ func newSqliteStore(path string) (*sqliteStore, error) {
 		return nil, fmt.Errorf("sqlite ping: %w", err)
 	}
 
+	if _, err := db.Exec("PRAGMA foreign_keys = ON"); err != nil {
+		db.Close()
+		return nil, fmt.Errorf("enable foreign keys: %w", err)
+	}
+
 	goose.SetBaseFS(embedMigrations)
 
 	if err := goose.SetDialect("sqlite3"); err != nil {
@@ -233,6 +238,33 @@ func (s *sqliteStore) getByPublicIDAndVersion(ctx context.Context, publicID int6
 	return &e, nil
 }
 
+func (s *sqliteStore) saveVote(ctx context.Context, flashcardID int64, value int, user, repo, message string) (*vote, error) {
+	_, err := s.db.ExecContext(ctx,
+		`INSERT INTO vote (flashcard_id, value, "user", repo, message)
+		 VALUES (?, ?, ?, ?, ?)
+		 ON CONFLICT(flashcard_id, "user", repo)
+		 DO UPDATE SET value = excluded.value, message = excluded.message`,
+		flashcardID, value, user, repo, message,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("upsert vote: %w", err)
+	}
+
+	row := s.db.QueryRowContext(ctx,
+		`SELECT _id, flashcard_id, value, "user", repo, message, created
+		 FROM vote WHERE flashcard_id = ? AND "user" = ? AND repo = ?`,
+		flashcardID, user, repo,
+	)
+
+	var v vote
+	err = row.Scan(&v.ID, &v.FlashcardID, &v.Value, &v.User, &v.Repo, &v.Message, &v.Created)
+	if err != nil {
+		return nil, fmt.Errorf("read vote: %w", err)
+	}
+
+	return &v, nil
+}
+
 func (s *sqliteStore) tombstone(ctx context.Context, publicID int64, version int) (int64, error) {
 	result, err := s.db.ExecContext(ctx,
 		`INSERT INTO flashcard (public_id, version, note, delete_timestamp)
diff --git a/types.go b/types.go
index 45d33a3..cb5f4f0 100644
--- a/types.go
+++ b/types.go
@@ -14,6 +14,16 @@ type entry struct {
 	Created         string   `json:"created"`
 }
 
+type vote struct {
+	ID          int64  `json:"_id"`
+	FlashcardID int64  `json:"flashcard_id"`
+	Value       int    `json:"value"`
+	User        string `json:"user"`
+	Repo        string `json:"repo"`
+	Message     string `json:"message"`
+	Created     string `json:"created"`
+}
+
 type searchResult struct {
 	Entry entry   `json:",inline"`
 	Score float32 `json:"score"`