[benbrandt]

Summary

Step 7 of the incremental extraction tracked in #655, directly against current main after #684. This is read-only configuration reporting, not historical work outcomes or child controls.

• Extend standard child configuration from model-only reports to complete reported model/reasoning-effort snapshots. Every select offers only its observed current value; neither parent values nor requested spawn arguments supply child values.
• Preserve the existing model-source precedence and model labels. Newer observations remove unset/unavailable effort, including empty snapshots when no fields remain reportable. A model change cannot carry the previous model's effort.
• Keep recorded configuration historical. Reattachment drops cached confirmation; fresh observations and verified, loaded provider metadata establish current configuration after the actual response write, including whole JSON-RPC batches.
• Run optional metadata reads outside the notification lane and rejoin that lane only to publish. Newer observations, unload/close, or another attachment invalidate late results. Reads verify the physical child ID and immediate parent without loading or changing the child.
• Ignore foreign runtime starts for history-only children; copied associations do not establish current configuration or ownership.

V1 standard opt-in, v2 defaults, empty child capabilities, mutation restrictions, and AIR's existing contract remain unchanged. AIR's only source change is exporting the existing source-priority constant for reuse. Dependencies and generated app-server types are untouched. Existing AIR and parent-session snapshots have no changes.

Review size

9 files, +653/-36 lines. About four fifths of the additions are tests/snapshots. Runtime changes stay within the standard router, its server wiring, and a small shared snapshot builder used by live and historical reporting.

Validation

• npm run typecheck
• npm test: 2,028 passed, 39 skipped. Includes 33 new v1/v2 wire regressions, with one v2-only batch case skipped on v1.
• npm run build
• npm run test:integration: 15 passed against real Codex 0.164.0 and a local mock Responses API. Native child tests now compare reported effort with the child's actual Responses request, both initially and after parent reattachment.
• npm run bundle:all: all six platform targets compiled.
• npm run codex-test -- -p 'Reply with exactly child-configuration-ok. Do not read files or use tools.' -c <isolated-scratch-directory> -o summary: live-model smoke completed with end_turn.
• git diff --check

Wire tests cover complete singleton snapshots, effort-only/unknown/cleared values, model changes, source precedence and pre-announcement buffering, no-op mutation rejection, changed and unchanged reattachment snapshots, full and no-replay attachment, delayed batches, pending reads without blocked output, newer native settings, late reads across attachments/unload/close, untrusted metadata, and historical-only configuration.

The full live-model E2E suite was not run. Cross-platform bundles were compiled, not executed on each target OS.

Protocol / reference check

• Specification main at 53620d0b325d6815b3cff1ca7e909351d488fdf0: RFD child configuration supplies the proposed child reporting, singleton-choice, and reattachment semantics. Existing draft configuration notifications require complete state in v1 and v2.
• TypeScript SDK main at c7e07388feed7a530f8211d0dae4951cb6d26d09, with the installed SDK 2.0.2 used for real wire decoding/schema checks. SDK runtime evidence is separate from the specification; the existing actual-write response boundary and ordered session-transition helper are reused, not replaced.
• Codex's generated Thread metadata documents model/effort as current configured values when loaded, or persisted values otherwise. Readback accepts only loaded, correctly parented children; persisted metadata alone does not confirm current configuration.

Historical work outcomes remain the next extraction. This PR does not merge or replace #655 wholesale.