A local child can have send_message available and still finish with a plain
text answer or use the tool only for progress. Selecting completion content
from tool availability drops that captured answer and leaves the parent
with a status-only notice. The recorded spawn case already demonstrates
this: its child returns CHILD_OK without calling the available tool.
Remove the includeClosingText policy and pass every captured final text
through the existing text-only notice renderer. Preserve structured
results, safe diagnostics, external continuation wording, and caller-only
result delivery. No delivery ledger or additional lifecycle state is
needed. A child that sends its final answer explicitly may repeat it in the
completion notice; that cost is preferable to making result delivery
depend on model compliance.
Extend the real-loop parent-result regression with an available-but-unused
messaging tool, restore the unconditional lifecycle expectation, and pin
text alongside structured results and diagnostics. The new regression
fails on the prior implementation because CHILD_RESULT_42 is missing.
Update the owning bilingual descriptions and the exact parent notice
content in headless and TypeScript SDK recordings. Keep replay streams,
released generations, and unrelated recorded clocks unchanged.
Validation: 317 focused lifecycle/workflow tests; full build; 26 focused
headless/SDK replays; Python SDK advanced/recovery smoke (unchanged
fixtures); test:docs (20 gates); doc-sync (42 gates); full lint;
git diff --check.
Tianyi Cui
f52167746c