fix(cli,hub): wire Cursor --existing-session-id for ACP remote resume (#991) (#1128)

Hub already passes access.sessionId on resume (#1088); Cursor CLI still ignored
it (Codex-only). Parse/pass the flag for cursor and lock in reuse-without-ready-wait tests.

Co-authored-by: Debian <heavygee@oos-linux.in.lockhouse>
Co-authored-by: Cursor <cursoragent@cursor.com>

cli/src/commands/cursor.ts

@@ -13,6 +13,7 @@ export type ParsedCursorCommandOptions = {
     cursorAddDirs?: string[]
     permissionMode?: CursorPermissionMode
     resumeSessionId?: string
+    existingSessionId?: string
     model?: string
 }
 
@@ -84,6 +85,12 @@ export function parseCursorCommandArgs(commandArgs: string[]): ParsedCursorComma
             } else {
                 unknownArgs.push(arg)
             }
+        } else if (arg === '--existing-session-id') {
+            const hapiSessionId = commandArgs[++i]
+            if (!hapiSessionId || hapiSessionId.startsWith('-')) {
+                throw new Error('Missing --existing-session-id value')
+            }
+            options.existingSessionId = hapiSessionId
         } else if (arg === '--continue') {
             unknownArgs.push(arg)
         } else if (arg === '--hapi-starting-mode') {

cli/src/runner/buildCliArgs.test.ts

@@ -119,7 +119,7 @@ describe('buildCliArgs', () => {
 
 
 
-    it('does not pass Codex-only existing session id flag to non-Codex agents', () => {
+    it('does not pass existing session id flag to agents that do not reuse HAPI rows', () => {
         const args = buildCliArgs('claude', {
             directory: '/tmp',
             resumeSessionId: 'claude-session-1',
@@ -131,6 +131,18 @@ describe('buildCliArgs', () => {
         expect(args).not.toContain('hapi-session-1')
     })
 
+    it('passes --existing-session-id for cursor resume when sessionId is set (#991)', () => {
+        const args = buildCliArgs('cursor', {
+            directory: '/tmp',
+            resumeSessionId: 'cursor-csid-1',
+            sessionId: 'hapi-session-991',
+        })
+        expect(args).toContain('--existing-session-id')
+        expect(args).toContain('hapi-session-991')
+        expect(args).toContain('--resume')
+        expect(args).toContain('cursor-csid-1')
+    })
+
     it('validates all known permission modes', () => {
         for (const mode of ['default', 'acceptEdits', 'auto', 'bypassPermissions', 'plan', 'ask', 'debug', 'autoReview', 'read-only', 'safe-yolo', 'yolo']) {
             const args = buildCliArgs('claude', {

cli/src/runner/run.ts

@@ -1115,7 +1115,10 @@ export function buildCliArgs(
     }
   }
   args.push('--hapi-starting-mode', 'remote', '--started-by', 'runner');
-  if (agent === 'codex') {
+  // Codex import/resume (#1088) and Cursor ACP remote resume (#991) both reuse
+  // the original HAPI row via --existing-session-id so the hub does not depend
+  // on session-ready over a remote socket before merge.
+  if (agent === 'codex' || agent === 'cursor') {
     const existingSessionId = options.existingSessionId ?? options.sessionId;
     if (existingSessionId) {
       args.push('--existing-session-id', existingSessionId);