diff --git a/packages/server/src/server/agent/mcp-parity.e2e.test.ts b/packages/server/src/server/agent/mcp-parity.e2e.test.ts
index 80d6da20a7..4b81efb607 100644
--- a/packages/server/src/server/agent/mcp-parity.e2e.test.ts
+++ b/packages/server/src/server/agent/mcp-parity.e2e.test.ts
@@ -186,8 +186,8 @@ function createRecordingAgentClients(): Record<AgentProvider, AgentClient> {
     if (client.listCommands) {
       wrappedClient.listCommands = async (config) => await client.listCommands!(config);
     }
-    if (client.listFeatures) {
-      wrappedClient.listFeatures = async (config) => await client.listFeatures!(config);
+    if (client.listControls) {
+      wrappedClient.listControls = async (config) => await client.listControls!(config);
     }
     if (client.listImportableSessions) {
       wrappedClient.listImportableSessions = async (options) =>
diff --git a/packages/server/src/server/agent/providers/acp-agent.test.ts b/packages/server/src/server/agent/providers/acp-agent.test.ts
index a4da489c22..17834e0490 100644
--- a/packages/server/src/server/agent/providers/acp-agent.test.ts
+++ b/packages/server/src/server/agent/providers/acp-agent.test.ts
@@ -1959,13 +1959,19 @@ describe("ACPAgentSession options against an ACP agent", () => {
     ]);
   });
 
-  test("a removal writes the select's empty choice and returns nothing when that took", async () => {
+  test("a removal writes the select's empty choice and returns it, since the options hold what the session runs", async () => {
     const { session, optionEvents } = await openSession({ agent: "Probe Agent" });
 
-    await expect(session.applyOptions({ agent: null })).resolves.toEqual({});
+    await expect(session.applyOptions({ agent: null })).resolves.toEqual({ agent: "" });
     expect(optionEvents).toEqual([]);
   });
 
+  test("a removal of a select already on its empty choice returns that choice too", async () => {
+    const { session } = await openSession({ agent: "" });
+
+    await expect(session.applyOptions({ agent: null })).resolves.toEqual({ agent: "" });
+  });
+
   test("rejects a live auto_accept the creation schema would reject, and writes nothing", async () => {
     const { session, optionEvents } = await openSession({
       scenario: { onWrite: "notify-then-reject" },
diff --git a/packages/server/src/server/agent/providers/acp-agent.ts b/packages/server/src/server/agent/providers/acp-agent.ts
index 4ca469be54..12e2e8f65b 100644
--- a/packages/server/src/server/agent/providers/acp-agent.ts
+++ b/packages/server/src/server/agent/providers/acp-agent.ts
@@ -2476,10 +2476,12 @@ export class ACPAgentSession implements AgentSession, ACPClient {
         for (const [id, value] of Object.entries(options)) {
           const featureOption = this.configFeatureOptions.find((candidate) => candidate.id === id);
           if (!featureOption) continue;
-          // A removal asks for the select's empty choice; a provider without one rejects it.
-          requested[id] = value ?? "";
+          // A removal asks for the select's empty choice; a provider without one rejects it. The
+          // choice it lands on is reported against the `null` that was asked, so the options
+          // hold the value the session runs with.
+          requested[id] = value;
           const option = findSelectConfigFeatureOption(this.configOptions, featureOption);
-          if (!option || requested[id] !== option.currentValue) {
+          if (!option || (value ?? "") !== option.currentValue) {
             await this.setConfigFeature(id, value);
           }
         }
diff --git a/packages/server/src/server/agent/providers/codex-app-server-agent.local.e2e.test.ts b/packages/server/src/server/agent/providers/codex-app-server-agent.local.e2e.test.ts
index dc7f920993..76c46c1d5c 100644
--- a/packages/server/src/server/agent/providers/codex-app-server-agent.local.e2e.test.ts
+++ b/packages/server/src/server/agent/providers/codex-app-server-agent.local.e2e.test.ts
@@ -386,7 +386,7 @@ describe("Codex app-server provider (local e2e)", () => {
         );
 
         try {
-          await session.setFeature?.("plan_mode", true);
+          await session.applyOptions!({ plan_mode: true });
 
           const events: AgentStreamEvent[] = [];
           session.subscribe((event) => {
diff --git a/packages/server/src/server/agent/providers/codex-plan-mode.real.e2e.test.ts b/packages/server/src/server/agent/providers/codex-plan-mode.real.e2e.test.ts
index 7c55a5f0f7..1582e6101f 100644
--- a/packages/server/src/server/agent/providers/codex-plan-mode.real.e2e.test.ts
+++ b/packages/server/src/server/agent/providers/codex-plan-mode.real.e2e.test.ts
@@ -40,7 +40,7 @@ describe("Codex app-server provider (real) plan mode", () => {
       });
 
       try {
-        await session.setFeature?.("plan_mode", true);
+        await session.applyOptions!({ plan_mode: true });
 
         const result = await session.run(
           "You are in plan mode. Produce a markdown plan with a short heading and exactly 3 bullets for implementing a login screen. Do not ask questions.",