diff --git a/src/agent/prompts/workspace.ts b/src/agent/prompts/workspace.ts
index 7142220..dfe39e5 100644
--- a/src/agent/prompts/workspace.ts
+++ b/src/agent/prompts/workspace.ts
@@ -16,7 +16,7 @@ export function buildWorkspaceLayout(agentCwd: string): string {
   }
 
   if (entries.length === 0) {
-    return `\n\n## Workspace Layout\n\nYour working directory is: ${agentCwd}`;
+    return `\n\n## Workspace Layout\n\nYour working directory is: ${agentCwd}\nThis is an isolated git worktree. Other agents may be working in parallel on separate branches — do not assume you have exclusive access to the repository.`;
   }
 
   const lines = entries.map(
@@ -26,6 +26,7 @@ export function buildWorkspaceLayout(agentCwd: string): string {
   return `\n\n## Workspace Layout
 
 Your working directory is: ${agentCwd}
+This is an isolated git worktree. Other agents may be working in parallel on separate branches — do not assume you have exclusive access to the repository.
 The following project directories contain the source code (git worktrees):
 
 ${lines.join('\n')}`;
diff --git a/src/dispatch/manager.test.ts b/src/dispatch/manager.test.ts
index 2823d99..b72783c 100644
--- a/src/dispatch/manager.test.ts
+++ b/src/dispatch/manager.test.ts
@@ -397,11 +397,11 @@ describe('DefaultDispatchManager', () => {
       const updatedTask = await taskRepository.findById(task.id);
       expect(updatedTask!.status).toBe('in_progress');
 
-      // Check spawn was called with correct params
+      // Check spawn was called with correct params (prompt is wrapped by buildExecutePrompt)
       expect(agentManager.spawn).toHaveBeenCalledWith(
         expect.objectContaining({
           taskId: task.id,
-          prompt: 'Do the thing',
+          prompt: expect.stringContaining('Do the thing'),
         })
       );
     });
diff --git a/src/dispatch/manager.ts b/src/dispatch/manager.ts
index 59a1e06..c940d2a 100644
--- a/src/dispatch/manager.ts
+++ b/src/dispatch/manager.ts
@@ -23,6 +23,7 @@ import type { PhaseRepository } from '../db/repositories/phase-repository.js';
 import type { Task } from '../db/schema.js';
 import type { DispatchManager, QueuedTask, DispatchResult } from './types.js';
 import { phaseBranchName, taskBranchName, isPlanningCategory, generateInitiativeBranch } from '../git/branch-naming.js';
+import { buildExecutePrompt } from '../agent/prompts/index.js';
 import { createModuleLogger } from '../logger/index.js';
 
 const log = createModuleLogger('dispatch');
@@ -371,7 +372,7 @@ export class DefaultDispatchManager implements DispatchManager {
       taskId: nextTask.taskId,
       initiativeId: task.initiativeId ?? undefined,
       phaseId: task.phaseId ?? undefined,
-      prompt: task.description || task.name,
+      prompt: buildExecutePrompt(task.description || task.name),
       baseBranch,
       branchName,
     });