Linear-created Codex Cloud sessions time out with new_ack_timeout

Open 💬 0 comments Opened Aug 8, 2026 by hugoJuhel

What issue are you seeing?

Description

Delegating a Linear issue to Codex Cloud previously worked normally but suddenly stopped on August 6, 2026.

Linear creates the Codex agent session successfully, but Codex Cloud never acknowledges it and no task starts. There is no start message, progress update, task link, visible error, or completion result. Repeated attempts only create additional orphaned Linear agent sessions.

Expected behavior

After Linear creates and sends the agent session, Codex Cloud should acknowledge it and start the corresponding task.

Actual behavior

Codex Cloud does not acknowledge the new session. The session eventually expires with:

new_ack_timeout

Verification performed by Linear Support

Linear Support investigated the affected sessions and confirmed that:

Linear successfully created the Codex sessions;
the Codex webhook was active and valid;
the repository remained accessible with write/admin permissions;
the missing acknowledgement came from Codex Cloud;
the sessions timed out before any task could start.

Troubleshooting already attempted

Disconnected and reconnected the Linear/Codex integration.
Reauthorized the integration.
Recreated the Codex Cloud environment.
Confirmed that direct Codex Cloud tasks still work.
Confirmed that the GitHub repository remains accessible.

None of these steps resolved the Linear delegation failure.

Scope

Integration: Linear → Codex Cloud
First observed: August 6, 2026
Repository: kyogo-Inc/core.apps
Affected issue: KYO-54
Multiple attempts reproduced the same failure.
Workspace and session identifiers are available privately to OpenAI staff.

Could the Codex Cloud integrations team investigate the session-acknowledgement path and determine whether the workspace authorization or Linear-to-Codex handshake requires a server-side reset?

What steps can reproduce the bug?