ratatoskr/persistent-memory.d/2026-07-19-worldtree-sdk-cutover-slice-7-complete.md

worldtree-sdk cutover — SLICE-7 (teardown, the LAST slice) COMPLETE

[2026-07-19] Commit ec68b1f feat(#20): worldtree-sdk cutover teardown (slice-7) + v0.22.0, tag v0.22.0 (lightweight). Closes issue #20's implementation: all 7 slices done, suite 494 green. This slice is teardown only — zero runtime-logic change; the green suite is the regression gate.

What slice-7 did

1. Dropped httpx-sse from pyproject.toml + lockfile. Slice-6 deleted its last user (sse_client.stream_admin_events); a tree grep confirmed nothing imports httpx_sse. uv sync physically pruned it from the venv; suite green with the module absent (empirical safety proof — a heid bug-hunt would find nothing on a proven-unused dep removal, so it was skipped with that reasoning).
2. Module-boundary decision — KEEP (operator decision A1, surfaced via /elitk + AskUserQuestion). Post-cutover sessions.py (227 LOC) and sse_client.py (170 LOC) hold NO client — only ratatoskr's caller-semantic exception surface + a couple of dataclasses (BifrostBinding; SseId, AdminEvent) + the endpoint_for_plane provider helper. Three options weighed:
   • A1 (chosen) — keep as-is, fix the misleading docstrings. Zero import churn, zero risk.
   • A2 — rename to session_errors.py/stream_errors.py, re-point ~7 importers. Honest names but pure polish nobody asked for, right before a milestone.
   • A3 — consolidate into one errors.py / fold into wt.py. Blocked by the AgentNotAvailable name collision (two distinct classes: persona-404 in sessions vs eager-turn-409 in sse_client) which would force renaming a contract-level caller-semantic type + its §Error-map rows + all catch sites; folding into wt.py also mis-homes endpoint_for_plane (provider-side) and balloons the adapter. Naming-honesty (principle-2) addressed by a one-line docstring note instead.
   • Resolves the slice-6 deferred item (contract line ~326): the ratatoskr AdminEvent/SseId + exceptions stay in sse_client.py; the session/tier3 exceptions + BifrostBinding stay in sessions.py.
   • The class-identity foot-gun holds: exception homes must never be run as __main__ (else a -m CLI's except binds a second copy). sessions.py/sse_client.py/wt.py are all safe; tier3.py/cli.py are not.
3. Retired wire contracts #2 (sessions) + #15 (tier3) — DEC-1 phase-2. Files DELETED (docs/contracts/issues/{2,15}.contract.md). Their normative authority transferred to the cutover contract at authoring; the code they specified is gone. #1 (SSE event vocabulary) NOT retired — stays current (amended 4bd9abd 2026-07-18) as ratatoskr's SSE-rendering reference; first_message NOT retired (ratatoskr-owned usage contract). Accepted side-effect: issues/5.contract.md's historical "amended #2/#3/#4 in-place" line now points at a deleted #2 — left as-is (frozen issue-record of a past action; NOT expanding DEC-1's #2/#15 retirement scope, which was heid-reviewed + operator-set).
4. Final coverage-map re-anchor. GET /sessions/{id}/tools → wt.py get_session_tools (SDK sessions.tools) → web/server.py (old sessions.py→tui.py row was stale; TUI already deleted). list_sessions re-homed to wt.py, still caller-less (picker was a TUI frontier, now moot). The Last-Event-ID SSE-resume sub-gap CLOSED — reconnect_turn deleted, resume folded into wt.py stream_turn auto-resume. Surface-2 SSE parsing re-anchored to the SDK (_envelope_for_type gone).
5. Stale doc-rot fix — the cli.py transport comment no longer calls seed_preset_first_message "not-yet-migrated hand-rolled" (it rides wt.write_authored_history since slice-3).
6. v0.22.0 (minor, DEC-6, operator-approved 2026-07-19) — publishes the full 6-slice cutover milestone.

Verification

• Suite 494 green (clean env: env -u RATATOSKR_ADMIN_API_KEY -u RATATOSKR_API_KEY -u WORLDTREE_API_KEY or venv-active with those keys unset).
• httpx_sse gone from the venv (import httpx_sse → ModuleNotFoundError); 0 refs in uv.lock; 0 in src/.
• Cutover contract still validates (only the expected no-FN-block warnings for a migration contract).
• No residual hand-rolled consumer HTTP paths: every httpx.AsyncClient construction outside wt.py (cli/tier3/web/entrypoint) feeds wt.build_client(transport=…) per INV-CUT-1; zero raw .get/.post bypass calls. Bifrost PROVIDER planes stay hand-rolled (INV-CUT-3, untouched).

Pending (non-blocking, operator's call)

• git push origin — ec68b1f + the v0.22.0 tag are LOCAL only.
• althing announce of v0.22.0 to worldtree-dev / wtsdk-dev per the SemVer push-notify (post-push; Rata is the SDK reference consumer, wt #371).

Discovered during the slice (not bugs)

• Phantom stale-LSP diagnostics flagged test_sse_client.py + slice6_smoke.py — neither exists on disk or in git (both deleted in slice-6). The in-venv 494-green suite is authoritative over Pyright, which resolves against system Python (all the worldtree_sdk/starlette/respx "unresolved import" noise).

See per-slice arc files [[2026-07-19-worldtree-sdk-cutover-slice-5-complete]], [[2026-07-19-worldtree-sdk-cutover-slice-6-complete]] for the earlier slices; design in auto-memory project_worldtree_sdk_cutover.