🪲 BUG: deduplicate and validate MCP server list input

src/features/settings/mcpServerList.ts

@@ -14,9 +14,14 @@ export function parseServerLabel(label: string): string | null {
 }
 
 export function addServer(servers: string[], server: string): string[] {
-  return [...servers, server];
+  const trimmed = server.trim();
+  if (!trimmed || servers.some((existing) => existing.trim() === trimmed)) {
+    return [...servers];
+  }
+  return [...servers, trimmed];
 }
 
 export function removeServer(servers: string[], server: string): string[] {
-  return servers.filter((s) => s !== server);
+  const trimmed = server.trim();
+  return servers.filter((s) => s.trim() !== trimmed);
 }

test/mcpServerList.test.ts

@@ -28,6 +28,34 @@ test("addServer appends without mutating the input", () => {
   assert.deepEqual(original, ["a"]);
 });
 
+test("addServer trims whitespace from the new command", () => {
+  const original = ["a"];
+  const next = addServer(original, "  b  ");
+  assert.deepEqual(next, ["a", "b"]);
+  assert.deepEqual(original, ["a"]);
+});
+
+test("addServer ignores empty or whitespace-only commands", () => {
+  const original = ["a"];
+  assert.deepEqual(addServer(original, ""), ["a"]);
+  assert.deepEqual(addServer(original, "   "), ["a"]);
+  assert.deepEqual(original, ["a"]);
+});
+
+test("addServer ignores duplicate commands", () => {
+  const original = ["a", "b"];
+  assert.deepEqual(addServer(original, "a"), ["a", "b"]);
+  assert.deepEqual(addServer(original, "  a  "), ["a", "b"]);
+  assert.deepEqual(original, ["a", "b"]);
+});
+
+test("addServer ignores duplicate commands when existing entries contain whitespace", () => {
+  const original = ["  a  ", "b"];
+  assert.deepEqual(addServer(original, "a"), ["  a  ", "b"]);
+  assert.deepEqual(addServer(original, "  a  "), ["  a  ", "b"]);
+  assert.deepEqual(original, ["  a  ", "b"]);
+});
+
 test("removeServer drops a matching entry without mutating the input", () => {
   const original = ["a", "b", "c"];
   const next = removeServer(original, "b");
@@ -38,3 +66,14 @@ test("removeServer drops a matching entry without mutating the input", () => {
 test("removeServer is a no-op when the command isn't found", () => {
   assert.deepEqual(removeServer(["a"], "missing"), ["a"]);
 });
+
+test("removeServer trims both sides so legacy whitespace-padded entries can be removed", () => {
+  assert.deepEqual(removeServer(["  a  ", "b"], "a"), ["b"]);
+  assert.deepEqual(removeServer(["a", "b"], "  a  "), ["b"]);
+});
+
+test("a server added via addServer can be removed via removeServer", () => {
+  const after = addServer(["a"], "  b  ");
+  assert.deepEqual(after, ["a", "b"]);
+  assert.deepEqual(removeServer(after, "b"), ["a"]);
+});