@@ -511,19 +511,19 @@ function rawProtocolRequestParam(
   return typeof params === "object" && params !== null ? Reflect.get(params, key) : undefined;
 }
 
-function rawProtocolPromptText(event: EffectAcpProtocol.AcpProtocolLogEvent): string {
+function rawProtocolPromptTextBlocks(
+  event: EffectAcpProtocol.AcpProtocolLogEvent,
+): Array<{ type: "text"; text: string }> {
   const prompt = rawProtocolRequestParam(event, "prompt");
-  if (!Array.isArray(prompt)) return "";
-  return prompt
-    .flatMap((block) =>
-      typeof block === "object" &&
-      block !== null &&
-      Reflect.get(block, "type") === "text" &&
-      typeof Reflect.get(block, "text") === "string"
-        ? [Reflect.get(block, "text") as string]
-        : [],
-    )
-    .join("\n");
+  if (!Array.isArray(prompt)) return [];
+  return prompt.flatMap((block) =>
+    typeof block === "object" &&
+    block !== null &&
+    Reflect.get(block, "type") === "text" &&
+    typeof Reflect.get(block, "text") === "string"
+      ? [{ type: "text" as const, text: Reflect.get(block, "text") as string }]
+      : [],
+  );
 }
 
 const pollProtocolMethods = (events: Queue.Queue<EffectAcpProtocol.AcpProtocolLogEvent>) =>
@@ -841,15 +841,26 @@ describe("AcpAdapterV2", () => {
           if (method === undefined) continue;
           methods.push(method);
           if (method === "session/prompt") {
-            return { methods, prompt: rawProtocolPromptText(event) };
+            const promptBlocks = rawProtocolPromptTextBlocks(event);
+            return {
+              methods,
+              prompt: promptBlocks.map((block) => block.text).join("\n"),
+              textBlockCount: promptBlocks.length,
+            };
           }
         }
       });
 
       const command = yield* runTurn(0, defaultPolicy, "/compact");
       assert.isTrue(command.prompt.startsWith("/compact"));
       assert.notInclude(command.prompt, "<t3_code_instructions>");
-      const firstDefault = yield* runTurn(1, defaultPolicy, "First default request.");
+      assert.equal(command.textBlockCount, 1);
+      const whitespaceCommand = yield* runTurn(1, defaultPolicy, "  /repro-skill");
+      assert.equal(whitespaceCommand.prompt, "  /repro-skill");
+      assert.equal(whitespaceCommand.textBlockCount, 1);
+      assert.notInclude(whitespaceCommand.prompt, "<t3_code_instructions>");
+      const firstDefault = yield* runTurn(2, defaultPolicy, "First default request.");
+      assert.equal(firstDefault.textBlockCount, 2);
       assert.include(firstDefault.prompt, "T3 Code interaction mode: Default");
       assert.include(firstDefault.prompt, "T3 Code collaborative browser");
       assert.include(firstDefault.prompt, "T3 Code orchestration");
@@ -859,19 +870,19 @@ describe("AcpAdapterV2", () => {
         "Build should preserve the agent's advertised mode default",
       );
       assert.include(
-        (yield* runTurn(2, defaultPolicy, "Second default request.")).prompt,
+        (yield* runTurn(3, defaultPolicy, "Second default request.")).prompt,
         "Second default request.",
       );
 
       const planPolicy = policy("plan");
-      const firstPlan = yield* runTurn(3, planPolicy, "Plan this change.");
+      const firstPlan = yield* runTurn(4, planPolicy, "Plan this change.");
       assert.include(firstPlan.prompt, "T3 Code interaction mode: Plan");
       assert.include(firstPlan.methods, "session/set_config_option");
       assert.include(
-        (yield* runTurn(4, planPolicy, "Continue planning.")).prompt,
+        (yield* runTurn(5, planPolicy, "Continue planning.")).prompt,
         "Continue planning.",
       );
-      const restoredBuild = yield* runTurn(5, defaultPolicy, "Implement the change.");
+      const restoredBuild = yield* runTurn(6, defaultPolicy, "Implement the change.");
       assert.include(restoredBuild.prompt, "T3 Code interaction mode: Default");
       assert.include(
         restoredBuild.methods,
 
@@ -6316,6 +6316,7 @@ export const makeAcpAdapterV2 = Effect.fn("makeAcpAdapterV2")(function* (
             attachments: turnInput.message.attachments,
             resolveAttachmentPath: host.resolveAttachmentPath,
           });
+          const isNativeSlashCommand = turnInput.message.text.trimStart().startsWith("/");
           const text = t3AcpPromptWithInstructions({
             prompt: messageText,
             state: instructionState,
@@ -6365,13 +6366,15 @@ export const makeAcpAdapterV2 = Effect.fn("makeAcpAdapterV2")(function* (
               detail: "ACP turn requires non-empty text or attachments",
             });
           }
-          prompt.push({
-            type: "text",
-            text: buildRuntimeInstructions({
-              harness: flavor.runtimeHarness ?? driver,
-              model: turnInput.modelSelection.model,
-            }),
-          });
+          if (!isNativeSlashCommand) {
+            prompt.push({
+              type: "text",
+              text: buildRuntimeInstructions({
+                harness: flavor.runtimeHarness ?? driver,
+                model: turnInput.modelSelection.model,
+              }),
+            });
+          }
           return { prompt, instructionState: text === messageText ? undefined : instructionState };
         });