There are several critical issues related to `session_id`.

[jujumilk3]

First, session_id expires inconsistently. A week-old conversation's session_id still works, but sometimes a 2-day-old one is already gone.

Second, submitting a query with an expired or invalid session_id (e.g., "foobar", "helloworld") causes the Claude Agent SDK to terminate with exit code 1, displaying "Unknown Error." This error is identifiable—it should be labeled as an "invalid session_id error." Unfortunately, since the SDK is just a wrapper around the Claude Code CLI rather than a standalone Python package, I cannot fix this issue.

I think this needs stable session management and a validation API to check the session_id before submitting queries.

[qing-ant]

Session management has been substantially improved since this was filed. The SDK now includes:

• list_sessions() and get_session_messages() functions (v0.1.46, PR feat: add list_sessions and get_session_messages top-level functions #622)
• get_session_info() with tag and created_at fields (v0.1.50, PR feat: add tag/created_at to SDKSessionInfo + get_session_info #667)
• tag_session() and rename_session() functions (v0.1.49, PRs feat: add tag_session with Unicode sanitization #670, feat: add rename_session #668)
• Improved error handling for ProcessError with actual stderr output

For the "Unknown Error" on invalid session IDs, this is tracked in #472 (API errors returned as text instead of exceptions). Session expiration depends on the CLI's session file cleanup behavior which is configurable.

If you're still experiencing inconsistent session behavior on SDK v0.1.50, please open a new issue with specific reproduction steps and your current version. Closing as stale.