connection.md: recovery for hung attached session

[zachary-ai]

Adds a field-tested gotcha to interaction-skills/connection.md: when the daemon's attached tab has a hung renderer, every helper call (page_info(), js()) blocks forever with no error while the daemon log looks healthy. Documents how to diagnose via browser-level CDP over the raw socket and re-point the default session at a fresh tab, plus the trap that restart_daemon() only stops the daemon.

Hit in production on 20 Jul 2026 when a long-idle Mighty Networks feed tab stopped answering Runtime.evaluate and hung a scheduled scan for 10+ minutes.

🤖 Generated with Claude Code

---

Summary by cubic

Documents recovery for a hung attached CDP session and adds a close_tab() helper so agents can clean up tabs and avoid indefinite blocking. This prevents stuck page_info()/js() calls and provides a safe path to reattach to a fresh tab.

• New Features
  • Added close_tab(target_id=None) to close a page target and run ensure_real_tab().
  • Updated interaction-skills/connection.md with steps to diagnose a hung session via raw CDP, create/attach a fresh target, set the default session, and caveats about switch_tab() blocking and restart_daemon() only stopping the daemon.

^{Written for commit 75e1458. Summary will update on new commits.}

[browser-harness-review]

✅ Skill review passed

Reviewed 1 file(s) — no findings.

[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="helpers.py">

<violation number="1" location="helpers.py:152">
P2: Closing the current tab leaves `self.session` (in the daemon) pointing to a dead session. `ensure_real_tab()` may not always switch to a new tab — `current_tab()` can return the closed tab's URL (which doesn't start with INTERNAL), so the early-return path in `ensure_real_tab()` fires without calling `switch_tab()`. The daemon's stale-session auto-recovery on the next CDP call covers this, but there's a window where the next session-scoped call either fails or incurs a re-attach delay.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Fix all with cubic | Re-trigger cubic</sub>

[cubic-dev-ai]

P2: Closing the current tab leaves self.session (in the daemon) pointing to a dead session. ensure_real_tab() may not always switch to a new tab — current_tab() can return the closed tab's URL (which doesn't start with INTERNAL), so the early-return path in ensure_real_tab() fires without calling switch_tab(). The daemon's stale-session auto-recovery on the next CDP call covers this, but there's a window where the next session-scoped call either fails or incurs a re-attach delay.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At helpers.py, line 152:

<comment>Closing the current tab leaves `self.session` (in the daemon) pointing to a dead session. `ensure_real_tab()` may not always switch to a new tab — `current_tab()` can return the closed tab's URL (which doesn't start with INTERNAL), so the early-return path in `ensure_real_tab()` fires without calling `switch_tab()`. The daemon's stale-session auto-recovery on the next CDP call covers this, but there's a window where the next session-scoped call either fails or incurs a re-attach delay.</comment>

<file context>
@@ -143,6 +143,14 @@ def new_tab(url="about:blank"):
+    # targetId — the attached session's id is not closable directly.
+    tid = target_id or current_tab()["targetId"]
+    cdp("Target.closeTarget", targetId=tid)
+    ensure_real_tab()
+
 def ensure_real_tab():
</file context>