diff --git a/src/loop/prompts.ts b/src/loop/prompts.ts
index 3f65959..e54bf7d 100644
--- a/src/loop/prompts.ts
+++ b/src/loop/prompts.ts
@@ -1,6 +1,8 @@
 import { REVIEW_FAIL, REVIEW_PASS } from "./constants";
 
 const NEWLINE_RE = /\r?\n/;
+const SPAWN_TEAM_WITH_WORKTREE_ISOLATION =
+  "Spawn a team of agents with worktree isolation.";
 
 const hasProofInTask = (task: string, proof: string): boolean => {
   const proofLines = proof
@@ -47,7 +49,7 @@ export const buildWorkPrompt = (
   }
 
   parts.push(
-    `Spawn a team of agents. When all work is verified and once you have a proof that the task is completed, append "${doneSignal}" on its own final line.`
+    `${SPAWN_TEAM_WITH_WORKTREE_ISOLATION} When all work is verified and once you have a proof that the task is completed, append "${doneSignal}" on its own final line.`
   );
   return parts.join("\n\n");
 };
@@ -71,7 +73,7 @@ export const buildReviewPrompt = (
     `If the work is complete, end with "${REVIEW_PASS}" on its own final line.`
   );
   parts.push(
-    `Spawn a team of agents. Do not use "${doneSignal}" in your final line.`
+    `${SPAWN_TEAM_WITH_WORKTREE_ISOLATION} Do not use "${doneSignal}" in your final line.`
   );
   return parts.join("\n\n");
 };
diff --git a/tests/loop/prompts.test.ts b/tests/loop/prompts.test.ts
index 3888431..bcce0c5 100644
--- a/tests/loop/prompts.test.ts
+++ b/tests/loop/prompts.test.ts
@@ -28,6 +28,7 @@ test("buildWorkPrompt keeps task, optional sections, and done instruction", () =
   expect(prompt).toContain(
     'append "<promise>DONE</promise>" on its own final line.'
   );
+  expect(prompt).toContain("worktree isolation");
 });
 
 test("buildWorkPrompt does not duplicate proof when task already contains it", () => {
@@ -52,5 +53,6 @@ test("buildReviewPrompt includes pass and fail instructions and verification", (
   expect(prompt).toContain(`end with "${REVIEW_FAIL}" on its own final line`);
   expect(prompt).toContain(`end with "${REVIEW_PASS}" on its own final line`);
   expect(prompt).toContain("Proof requirements:\nmust pass ci");
+  expect(prompt).toContain("worktree isolation");
   expect(prompt).toContain('Do not use "<done/>" in your final line.');
 });