fix(pi): resume archived sessions safely (#1308)

* fix(pi): resume archived sessions safely

* fix(pi): harden native resume startup

* fix(pi): harden resume termination evidence

* fix(runner): persist resume process evidence

* fix(runner): track resume process generations

* fix(runner): verify full session tree shutdown

* fix(pi): block pre-mapping resume dedup

cli/src/commands/agentCommandOptions.test.ts

@@ -7,12 +7,14 @@ describe('parseRemoteAgentCommandOptions', () => {
         expect(parseRemoteAgentCommandOptions([
             '--started-by', 'runner',
             '--hapi-starting-mode', 'remote',
+            '--existing-session-id', 'hapi-session-1',
             '--permission-mode', 'yolo',
             '--resume', 'session-1',
             '--model', 'model-a'
         ], GEMINI_PERMISSION_MODES)).toEqual({
             startedBy: 'runner',
             startingMode: 'remote',
+            existingSessionId: 'hapi-session-1',
             permissionMode: 'yolo',
             resumeSessionId: 'session-1',
             model: 'model-a'
@@ -67,6 +69,7 @@ describe('parseRemoteAgentCommandOptions', () => {
         expect(() => parseRemoteAgentCommandOptions(['--resume'], OPENCODE_PERMISSION_MODES)).toThrow('Missing --resume value')
         expect(() => parseRemoteAgentCommandOptions(['--model'], OPENCODE_PERMISSION_MODES)).toThrow('Missing --model value')
         expect(() => parseRemoteAgentCommandOptions(['--model-reasoning-effort'], OPENCODE_PERMISSION_MODES)).toThrow('Missing --model-reasoning-effort value')
+        expect(() => parseRemoteAgentCommandOptions(['--existing-session-id'], OPENCODE_PERMISSION_MODES)).toThrow('Missing --existing-session-id value')
     })
 
     it('accepts OpenCode-native -s / --session as resume aliases', () => {
@@ -190,6 +193,7 @@ describe('parseRemoteAgentCommandOptions — pi flavor', () => {
                 '--hapi-starting-mode', 'remote',
                 '--model', 'claude-sonnet-4-5',
                 '--session-id', 'pi-sess-full',
+                '--existing-session-id', 'hapi-session-pi-full',
             ],
             ALLOWED
         )
@@ -198,6 +202,7 @@ describe('parseRemoteAgentCommandOptions — pi flavor', () => {
             startingMode: 'remote',
             model: 'claude-sonnet-4-5',
             resumeSessionId: 'pi-sess-full',
+            existingSessionId: 'hapi-session-pi-full',
         })
     })
 })

cli/src/commands/agentCommandOptions.ts

@@ -8,6 +8,7 @@ export type RemoteAgentCommandOptions<TPermissionMode extends PermissionMode> =
     effort?: string
     modelReasoningEffort?: string
     resumeSessionId?: string
+    existingSessionId?: string
 }
 
 export function parseRemoteAgentCommandOptions<TPermissionMode extends PermissionMode>(
@@ -28,6 +29,12 @@ export function parseRemoteAgentCommandOptions<TPermissionMode extends Permissio
             } else {
                 throw new Error('Invalid --hapi-starting-mode (expected local or remote)')
             }
+        } else if (arg === '--existing-session-id') {
+            const sessionId = args[++i]
+            if (!sessionId || sessionId.startsWith('-')) {
+                throw new Error('Missing --existing-session-id value')
+            }
+            options.existingSessionId = sessionId
         } else if (arg === '--permission-mode') {
             const mode = args[++i]
             if (!mode || !(allowedPermissionModes as readonly string[]).includes(mode)) {

cli/src/commands/runner.test.ts

@@ -16,7 +16,7 @@ const {
     checkIfRunnerRunningAndCleanupStaleStateMock: vi.fn(),
     listRunnerSessionsMock: vi.fn(async () => []),
     stopRunnerMock: vi.fn(async () => {}),
-    stopRunnerSessionMock: vi.fn(async () => true),
+    stopRunnerSessionMock: vi.fn(async (_sessionId: string): Promise<'stopped' | 'already_gone' | 'still_alive'> => 'stopped'),
     spawnHappyCLIMock: vi.fn(() => ({ unref: vi.fn() })),
     startRunnerMock: vi.fn(async () => {}),
     getLatestRunnerLogMock: vi.fn(async () => null),
@@ -127,3 +127,25 @@ describe('runnerCommand start', () => {
         }
     })
 })
+
+describe('runnerCommand stop-session', () => {
+    beforeEach(() => {
+        vi.clearAllMocks()
+    })
+
+    it.each([
+        ['stopped', 'Session stopped'],
+        ['already_gone', 'Session was already stopped'],
+        ['still_alive', 'Failed to stop session'],
+    ] as const)('renders the %s runner result', async (status, expected) => {
+        const consoleLogSpy = vi.spyOn(console, 'log').mockImplementation(() => {})
+        stopRunnerSessionMock.mockResolvedValueOnce(status)
+        try {
+            await runnerCommand.run(createContext(['stop-session', 'session-1']))
+            expect(stopRunnerSessionMock).toHaveBeenCalledWith('session-1')
+            expect(consoleLogSpy).toHaveBeenCalledWith(expected)
+        } finally {
+            consoleLogSpy.mockRestore()
+        }
+    })
+})

cli/src/commands/runner.ts

@@ -113,8 +113,14 @@ export const runnerCommand: CommandDefinition = {
             }
 
             try {
-                const success = await stopRunnerSession(sessionId)
-                console.log(success ? 'Session stopped' : 'Failed to stop session')
+                const status = await stopRunnerSession(sessionId)
+                if (status === 'stopped') {
+                    console.log('Session stopped')
+                } else if (status === 'already_gone') {
+                    console.log('Session was already stopped')
+                } else {
+                    console.log('Failed to stop session')
+                }
             } catch {
                 console.log('No runner running')
             }