[edwin-zvs]

The bug (found in the 'construct improvements' session)

After the planning pass declared a task pending, the agent dispatched a subagent, which moved the task into "In progress" and appended a @{session} clip — changing the block's text, hence its id (50eca… → 74c9…). The old id dropped from the pending set before the new id was declared, so the set transiently emptied; the daemon reaped the whole run on that empty; the agent's follow-up re-declaration of the new id hit a removed run and was a silent no-op. All shimmer vanished — exactly opposite the expectation (In-progress items should animate while subagents work).

The agent even diagnosed it in its own words:

"The move reset the block's shimmer to settled and the system won't re-light a settled/new block … That's a known constraint."

Fix #1 — survive a transient empty

narrow_program_run / set_program_run_pending no longer remove a run when its pending set empties; program_run_snapshot reports no active run on empty (nothing shimmers) but keeps the record so a later declaration revives it. An empty run is reaped only on a terminal owning-session state, the owning session going idle with nothing pending, or the inactivity backstop.

Fix #2 — atomic keep_pending

Re-introduce a per-edit ProgramEdit.keep_pending flag. An edit that changes a still-pending block re-adds the resulting block's new id in the same narrowing call (anchored on the edit's new_string), so a move/annotate never transiently empties the set and the agent needn't know the post-edit id. The call-level shimmer id-list still declares arbitrary existing blocks (the planning pass). Tool description + run prompts updated to steer agents to keep_pending for move/clip edits.

Specs

• 0042 — stop lifecycle: a transient empty mid-turn is not a stop; empty clears only on terminal/idle/backstop.
• 0048 — agent contract: use keep_pending (or re-declare) when editing an in-flight block.
• 0053 — both mechanisms (id-list vs keep_pending) and transient-empty survival.

Tests

Three new daemon tests — transient-empty survival + revival, keep_pending atomicity, empty-clears-on-idle — plus the #567/#569 tests unaffected. cargo test --workspace green.

Deploy note

The running daemon needs a /construct restart to pick this up (same as #567).

Relevant binary: construct (daemon + cli + mcp).