`[2026-07-06]` **#347 authored-history-write CONSUMER SIDE SHIPPED (`v0.19.6`) — direct in-session TDD.** `write_authored_history(client, session_id, *, content, idempotency_key, author="assistant", effects=None, claimed_original_at=None) -> dict` (POST /sessions/{id}/history; body server-pinned `AuthoredWriteRequest` extra="forbid" so omit null effects/claimed_original_at; 200-replay/201-fresh both -> ack dict; **404 -> `AuthoredHistoryUnavailable`** NOT SessionApiFailed = the hide-existence "feature-absent, never probe" contract; 409/422->SessionApiFailed) + `get_session_messages` (un-deferred GET /sessions/{id}/messages, the seed read-back proving model-invisible provenance) + a `--seed-first-message "<c>" --agent <id>` one-shot probe (create session -> seed -> read-back; 404->benign feature-absent exit 0). Contract #2 amended (2 FNs, validated OK) + 19 tests (12 wrapper + 7 cli). Suite **601 green** (clean env; the 2 "fails" under `source env.sh` are the RATATOSKR_ADMIN_API_KEY env-leak into TestParseArgs, not a regression). Coverage: **REST 19/41** (`docs/coverage-map.md` re-converged). Patch bump (coverage tail; consistent w/ the Tier-2 v0.19.1 cadence). **Live-proof pending** the `session.history.write` grant (infra-ops `01KWW3KQEY`). heid-code-review NOT run (offered).