Status: awaiting owner review.

Root cause:

• Parent nodes collected embedded-child output through loose child node_id output lookups, which allowed races, stale reads, and silent empty completions.
• The shared child_output helper also needed its json module binding, and cycle needed to preserve template context when strict collection returned a structured child failure.

Strict collection contract:

• Parents use the run_node_results returned by n:yield.
• child_output resolves those exact node.result rows, then resolves routed node.output rows from the result envelope data_ids.
• Structured result envelopes with no data_ids do not trigger node_id guessing.
• Legacy non-envelope fallback is scoped to the exact returned result row node_id.
• Output and error routing preserve target-provided data_id values so result envelopes match durable rows.

Failure modes fixed:

• Late child output now resolves from durable yield-returned result IDs instead of racing node output visibility.
• Crash recovery with pending children resumes and collects durable child output instead of completing empty.
• Cycle template child failures keep cycle/template failure context.

Test evidence:

• Initial full suite from owner WIP: 727 passed, 121 failed.
• After binding child_output json: 899 passed, 1 failed.
• Final full suite: make test -> 900 tests passed in 208.0s.

DESIGN_REVIEW.md summary:

• Documents the yield-result collection contract, invariants, file-level changes, risks, and design-gap record.
• No strict-contract design gaps were found; observed failures were implementation issues fixed in this branch.