feat(#20): admin (bifrost inspection + admin-events stream) onto the wt adapter (slice-6)

Slice-6 of the worldtree-sdk cutover: migrate the two admin routes off the
hand-rolled paths onto the `ratatoskr.wt` adapter over `client.admin.*`, and delete
the retired code. Both are web-only (the coverage-map's `tui.py` rows were stale —
corrected to `web/server.py`).

Adapter (`wt.py`): `get_session_bifrost` → `client.admin.sessions.bifrost` (open-world
dict verbatim, any error → SessionApiFailed default); `stream_admin_events` →
`client.admin.stream_events`, re-wrapping the SDK's `AdminEvent` → ratatoskr's at the
boundary.

Decisions (contract § slice-6 notes):
- Admin auth moves from a per-call `Authorization` header override to the client's
  `admin_auth` (`_wt_client(admin_key=…)`, extended this slice) — the SDK's admin.*
  routes use the provider, not a header.
- `AdminEvent` re-wrap (chosen over yield-through): the SDK's `admin_id`(nan)/None-able
  `type`/`data` diverge from ratatoskr's `id`/`type`/`data` that the web filter reads;
  re-wrapping (nan→0, None→""/{}) degrades the open-world None/nan ONCE at the adapter
  and keeps the web endpoint + `_admin_event_matches_web` + the `AdminEvent` domain type
  unchanged (preserves the web surface). Rejected: yield SDK events + rewire the web
  filter (heavier churn, scattered hardening).
- Admin-stream error map: a NON-200 open raises `ApiError("admin_stream_failed")`
  (NOT `ConnectFailed`) → SseConnectFailed; `ConnectionDropped` (connect-time OR
  mid-stream/resumable-EOF) → SseConnectionDropped. The web integration test caught the
  ApiError-not-ConnectFailed gotcha the unit fake couldn't.

Web (`web/server.py`): both admin endpoints build the wt client with admin_key and call
`wt.*`; the bifrost endpoint gains ConnectFailed→502 handling (cutover foot-gun); the
admin-events endpoint closes the injected transport (INV-CUT-1), never the wt client.

Deleted the hand-rolled `sessions.get_session_bifrost` + `sse_client.stream_admin_events`
(+ orphaned httpx/httpx_sse/json/AsyncIterator imports); the ratatoskr `AdminEvent`
dataclass stays in `sse_client.py` (re-wrap target, imported by wt + web) until slice-7.
Retired `test_sse_client.py` entirely (its last test was the admin stream) and the
`test_sessions.py` `TestGetSessionBifrost`; added the slice-6 adapter tests.

LIVE SMOKE (:8081, readonly-admin key) — INV-CUT-5 / DEC-4 cleared: the web bifrost
endpoint returned an admin-authed clean 404 envelope (auth + route + mapping proven);
a real `session.created` admin event (id=32) re-wrapped cleanly on live wire (driven by
a session-create, throwaway session cleaned up).

Suite 490 green; ruff clean; mypy net-improved on web/server.py (16→12 pre-existing, no
new). Patch bump 0.21.18 → 0.21.19 (the cutover MINOR is deferred to slice-7, DEC-6).

docs/contracts/worldtree_sdk_cutover.contract.md

@@ -295,6 +295,46 @@ re-anchor its coverage-map rows.
   web-server caller — only the `--whoami` and `--characters` CLI one-shot probes. The
   web surface is untouched this slice.
 
+### Slice-6 notes (Admin: bifrost inspection + admin-events stream, decided at TDD)
+
+- **Admin auth moves from a per-call header override to the client's `admin_auth`.**
+  The SDK's `admin.*` methods authenticate with the client's `admin_auth` provider
+  (set via `build_client(admin_key=...)`), NOT a per-request `Authorization` header. So
+  the two web admin endpoints build their wt client WITH `admin_key` (`_wt_client(client,
+  admin_key=...)`, extended this slice); the hand-rolled per-call `admin_key=` +
+  header-override is retired. The web already guards `if not admin_key: 400` before the
+  call, so the SDK's pre-HTTP `ConfigurationError` (missing admin_auth, W-5) is
+  unreachable from the web surface. **CLI has no admin caller** — both routes are
+  web-only (the coverage-map's `tui.py` rows were stale; corrected to `web/server.py`).
+- **`get_session_bifrost` — no new § Error map row.** `client.admin.sessions.bifrost`
+  returns the open-world `BifrostInspection` dict verbatim; any `ApiError` (notably 403
+  `auth_scope_denied`, 404 `session_not_bifrost_bound`) → the `SessionApiFailed` default
+  — exact parity with the retired path (which mapped every non-200 → `SessionApiFailed`).
+- **`stream_admin_events` re-wraps the SDK's `AdminEvent` → ratatoskr's `AdminEvent`
+  (chosen over yield-through).** The SDK's `AdminEvent` diverges from ratatoskr's:
+  `admin_id: int|float` (`nan` for an id-less envelope) vs ratatoskr's `id: int` (0
+  default), and the SDK's `type`/`data` are None-able where ratatoskr's are a dotted-str
+  / a `{}`-default dict. The web filter + SSE formatter read `ev.id`/`ev.type`/`ev.data`.
+  The adapter re-wraps at the boundary — `id = admin_id if int else 0` (nan→0),
+  `type = type or ""` (None→"" so `.startswith` never crashes), `data = data or {}` —
+  degrading the SDK's open-world None/nan ONCE at the adapter, keeping the web endpoint +
+  `_admin_event_matches_web` + the ratatoskr `AdminEvent` domain type UNCHANGED (preserves
+  the web surface per § Out of scope). **Rejected alternative:** yield SDK `AdminEvent`s
+  through and rewire the web filter for `admin_id`/None/nan (the slice-2 turn-stream
+  precedent) — heavier web churn + scatters the None/nan hardening through the filter;
+  re-wrap localizes it. The ratatoskr `AdminEvent` dataclass stays in `sse_client.py` this
+  slice (imported by `wt` + the web); its home moves in slice-7 teardown if `sse_client.py`
+  is retired.
+- **Admin-stream error mapping (reuses the § Error map stream rows).** The SDK admin
+  stream raises `ApiError("admin_stream_failed", status=…)` on a NON-200 open (NOT
+  `ConnectFailed` — a gotcha the web integration test caught that the unit fake could not)
+  → `SseConnectFailed`; and `ConnectionDropped` on a connect-time transport failure
+  (cursor None) OR a mid-stream drop / the long-lived stream's resumable EOF (cursor set)
+  → `SseConnectionDropped`. The SDK admin stream is best-effort (skips malformed frames —
+  no `Malformed*`), as was the retired hand-rolled path; the web endpoint's existing
+  `except (…, MalformedSseId, MalformedSseData)` stays a harmless defensive superset
+  (pre-existing, not introduced here).
+
 ## Out of scope
 
 - Bifrost PROVIDER planes (memory/affect) — hand-rolled, ADR-0009, untouched.

docs/coverage-map.md

@@ -97,8 +97,8 @@ sub-gap).
 | `GET /me` | ✅ | `wt.py` `get_me` (SDK `me.get`) → `cli.py` `--whoami` | **wt-adapter re-anchored (slice-5, #20)** — open-world identity dict verbatim; any error→SessionApiFailed default (401 on a bad/absent key), transport→ConnectFailed→exit 21. **LIVE-SMOKE 2026-07-19** on personal :8081 (b128): identity rendered (user_id ratatoskr, tier user, scopes incl. `character.*`, key_id c990f0be) |
 | `GET /capabilities` | ✅ | `wt.py` `get_capabilities` (SDK `capabilities.get`) → `cli.py` `--whoami` | **wt-adapter re-anchored (slice-5, #20)** — open-world advertisement verbatim; `_format_whoami` reads `allowed_roles`/`default_role` and degrades on a null/non-mapping template (slice-4 hardening); matches conversation-api-spec **v1.1** (`b4a278c`). **LIVE-SMOKE 2026-07-19**: `ephemeral_template echo: default=echo max_bytes=32768 roles=[echo]` |
 | `GET /sessions/{id}/tools` | ✅ | `sessions.py:411` `get_session_tools` → `tui.py` `_hydrate_session_tools` | owner-scoped tool inventory in the TUI Tools pane (#183) |
-| `GET /admin/sessions/{id}/bifrost` | ✅ | `sessions.py:428` `get_session_bifrost` → `tui.py` `_hydrate_bifrost_state` | admin-scoped BifrostState pane (#176); admin key (`RATATOSKR_ADMIN_API_KEY`); live-auth-proven |
+| `GET /admin/sessions/{id}/bifrost` | ✅ | `wt.py` `get_session_bifrost` (SDK `admin.sessions.bifrost`) → `web/server.py` `_session_bifrost_endpoint` | **wt-adapter re-anchored (slice-6, #20)** — admin-scoped BifrostState (#176); admin_auth rides on the wt client (`_wt_client(admin_key=…)`), NOT a per-call header; open-world dict verbatim, any error→SessionApiFailed default. **LIVE-SMOKE 2026-07-19** on :8081 (readonly-admin key): admin-authed end-to-end (404 `session_not_bifrost_bound` clean envelope — auth + route + mapping proven). (Consumer is `web/server.py`, not `tui.py` — the old row was stale.) |
-| `GET /admin/events` (SSE) | ✅ | `sse_client.py` `stream_admin_events` → `tui.py` `_stream_admin_events` | admin lifecycle SSE stream (#11), session-filtered AdminEvents pane; admin key; live-auth-proven |
+| `GET /admin/events` (SSE) | ✅ | `wt.py` `stream_admin_events` (SDK `admin.stream_events`) → `web/server.py` `_admin_events_endpoint` | **wt-adapter re-anchored (slice-6, #20)** — admin lifecycle SSE (#11), session-filtered; admin_auth on the wt client; the adapter re-wraps the SDK's `AdminEvent`→ratatoskr's (nan `admin_id`→id 0, None type/data→`""`/`{}`), non-200 open `ApiError`→SseConnectFailed, `ConnectionDropped`→SseConnectionDropped. **LIVE-SMOKE 2026-07-19**: a real `session.created` event (id=32) re-wrapped cleanly on live wire. (Consumer is `web/server.py`, not `tui.py` — stale row corrected.) |
 | `GET /models/available-for-characters` | ✅ | `wt.py` `list_character_models` (SDK `models.available_for_characters`) → `cli.py` `--characters` | **wt-adapter re-anchored (slice-5, #20)** — open-world catalog verbatim; the probe reads `items` null-safe (`or []`); any error→SessionApiFailed default. **LIVE-SMOKE 2026-07-19**: `character models: char-rp` |
 | `POST /characters` | ✅ | `wt.py` `create_character` (SDK `characters.create`) → `cli.py` `--characters` | **wt-adapter re-anchored (slice-5, #20)** — body `{character}` (+`state` only when set — SDK-idiomatic, drops the redundant explicit null); open-world create ACK verbatim; the probe degrades on a missing `character_id` (no hard-index). **LIVE-SMOKE 2026-07-19**: `created char_8c00006e…` |
 | `GET /characters/{id}/state` | ✅ | `wt.py` `get_character_state` (SDK `characters.state`) → `cli.py` `--characters` | **wt-adapter re-anchored (slice-5, #20)** — open-world live PAD/emotions verbatim; TTL-refreshing read. **LIVE-SMOKE 2026-07-19**: `state pad=[0.234, -0.136, 0.065]` read back |

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "ratatoskr"
-version = "0.21.18"
+version = "0.21.19"
 description = "Worldtree Conversation API debug console (web + headless CLI) — multi-pane observability"
 readme = "README.md"
 requires-python = ">=3.12"

src/ratatoskr/sessions.py

@@ -6,9 +6,6 @@ Implements docs/contracts/issues/2.contract.md.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import Any
-
-import httpx
 
 
 @dataclass(frozen=True)
@@ -228,28 +225,3 @@ def endpoint_for_plane(plane: str, base_host: str) -> str:
     if plane not in ports:
         raise ValueError(f"unknown plane: {plane!r} (expected 'memory', 'affect', or 'combined')")
     return f"http://{base_host}:{ports[plane]}"
-
-
-async def get_session_bifrost(
-    client: httpx.AsyncClient, session_id: str, *, admin_key: str
-) -> dict[str, Any]:
-    """GET /admin/sessions/{session_id}/bifrost — admin-scoped Bifrost dispatch state (#176).
-
-    Returns the live Bifrost binding for a session: `{endpoint_url, consumer_id,
-    connected, capabilities_granted, tools: [{name, description}]}`. Requires the
-    `admin.sessions.read` scope (admin tier), so the request OVERRIDES the
-    Authorization header with `admin_key` (distinct from the client's default
-    consumer key). Read-only (audited server-side). Parsed dict verbatim; any
-    non-200 → SessionApiFailed — notably 403 `auth_scope_denied` (key lacks the
-    scope) and 404 `session_not_bifrost_bound` (session exists, no live client).
-    """
-    assert client is not None
-    assert session_id and isinstance(session_id, str)
-    assert admin_key and isinstance(admin_key, str)
-    resp = await client.get(
-        f"/admin/sessions/{session_id}/bifrost",
-        headers={"Authorization": f"Bearer {admin_key}"},
-    )
-    if resp.status_code == 200:
-        return resp.json()
-    raise SessionApiFailed(status=resp.status_code, body=resp.content)

src/ratatoskr/sse_client.py

@@ -5,14 +5,9 @@ Implements docs/contracts/issues/1.contract.md.
 
 from __future__ import annotations
 
-import json
-from collections.abc import AsyncIterator
 from dataclasses import dataclass
 from typing import Any, NamedTuple
 
-import httpx
-import httpx_sse
-
 
 class SseId(NamedTuple):
     """Parsed composite SSE wire `id:` per spec §SSE id format."""
@@ -173,51 +168,3 @@ class CancelFailed(Exception):
         super().__init__(f"cancel failed: status={status}, body={body[:128]!r}")
         self.status = status
         self.body = body
-
-
-
-async def stream_admin_events(
-    client: httpx.AsyncClient,
-    *,
-    admin_key: str,
-    last_event_id: int | None = None,
-) -> AsyncIterator[AdminEvent]:
-    """GET /admin/events SSE — the admin-tier lifecycle broadcast stream (INV-046).
-
-    Yields `AdminEvent` envelopes as they arrive. Admin-scoped (admin.events.read):
-    the request OVERRIDES Authorization with `admin_key` (distinct from the
-    client's default consumer bearer). `last_event_id` sets the `Last-Event-ID`
-    header for resume (plain decimal int). Long-lived — iterate until the caller
-    stops or the connection ends. Non-200 → SseConnectFailed; a mid-stream drop
-    → SseConnectionDropped (caller may reconnect from the last-seen `AdminEvent.id`).
-    Malformed frames are skipped (best-effort stream).
-    """
-    assert client is not None
-    assert admin_key and isinstance(admin_key, str)
-    headers = {"Authorization": f"Bearer {admin_key}"}
-    if last_event_id is not None:
-        headers["Last-Event-ID"] = str(last_event_id)
-    async with httpx_sse.aconnect_sse(
-        client, "GET", "/admin/events", headers=headers
-    ) as event_source:
-        if event_source.response.status_code != 200:
-            body = await event_source.response.aread()
-            raise SseConnectFailed(status=event_source.response.status_code, body=body)
-        try:
-            async for sse in event_source.aiter_sse():
-                if sse.data == "":
-                    continue
-                try:
-                    env = json.loads(sse.data)
-                except json.JSONDecodeError:
-                    continue  # skip a malformed admin frame (best-effort)
-                yield AdminEvent(
-                    id=env.get("id", 0),
-                    type=env["type"],
-                    timestamp=env.get("timestamp"),
-                    data=env.get("data", {}),
-                )
-        except (httpx.ReadError, httpx.RemoteProtocolError, httpx.ReadTimeout) as exc:
-            raise SseConnectionDropped(last_seen_sse_id=None) from exc
-
-

src/ratatoskr/web/server.py

@@ -45,15 +45,14 @@ from ratatoskr.sessions import (
     BifrostConsumerKeyMissing,
     BifrostHandshakeFailed,
     PersonaNotConfigured,
-    SessionApiFailed,
     endpoint_for_plane,
-    get_session_bifrost,
 )
 
-# The turn path (create / stream / cancel / tools / messages) AND the agents /
+# The turn path (create / stream / cancel / tools / messages), the agents /
-# persona-state reads are served by the worldtree-sdk adapter (`wt.*`), which raises
+# persona-state reads, AND the admin surface (bifrost inspection + admin-events stream)
-# ratatoskr's caller-semantic exceptions (DEC-2). The remaining hand-rolled endpoint
+# are all served by the worldtree-sdk adapter (`wt.*`), which raises ratatoskr's
-# (admin bifrost) stays on the `sessions` / `sse_client` wrappers until slice 6.
+# caller-semantic exceptions (DEC-2). `AdminEvent` is still ratatoskr's domain event
+# type the adapter re-wraps into (imported from `sse_client` until slice-7 teardown).
 from ratatoskr.sse_client import (
     AdminEvent,
     CancelAlreadyCompleted,
@@ -64,16 +63,21 @@ from ratatoskr.sse_client import (
     SseConnectFailed,
     SseConnectionDropped,
     TurnIdFlip,
-    stream_admin_events,
 )
 
 
-def _wt_client(client: httpx.AsyncClient, *, max_reconnects: int = 5) -> WorldtreeClient:
+def _wt_client(
+    client: httpx.AsyncClient, *, admin_key: str | None = None, max_reconnects: int = 5
+) -> WorldtreeClient:
     """Wrap a client_factory transport as the adapter's WorldtreeClient (INV-CUT-1:
     the SDK never closes it). base_url + bearer are read off the transport (the
     factory bakes them in); the SDK re-applies auth per request, so the extracted
     key just mirrors the transport's default. A no-auth test transport falls back to
-    a placeholder key (respx ignores auth)."""
+    a placeholder key (respx ignores auth).
+
+    `admin_key` is the SERVER-HELD admin credential (slice-6): the SDK's `admin.*`
+    routes authenticate with the client's `admin_auth`, NOT a per-call header, so an
+    admin endpoint passes it here. Omitted for the default-tier reads."""
     base_url = str(client.base_url) or "http://localhost"
     header = client.headers.get("Authorization", "")
     # Case-insensitive scheme + tolerant of extra whitespace, so a valid bearer is
@@ -81,7 +85,11 @@ def _wt_client(client: httpx.AsyncClient, *, max_reconnects: int = 5) -> Worldtr
     parts = header.split(None, 1)
     api_key = parts[1].strip() if len(parts) == 2 and parts[0].lower() == "bearer" else ""
     return wt.build_client(
-        base_url, api_key=api_key or "ratatoskr", transport=client, max_reconnects=max_reconnects
+        base_url,
+        api_key=api_key or "ratatoskr",
+        admin_key=admin_key,
+        transport=client,
+        max_reconnects=max_reconnects,
     )
 
 
@@ -573,14 +581,24 @@ async def _session_bifrost_endpoint(request: Request) -> JSONResponse:
         return JSONResponse({"error_code": "admin_key_not_configured"}, status_code=400)
     client_factory = request.app.state.client_factory
     try:
-        async with client_factory() as client:
+        async with client_factory() as transport:
-            bstate = await get_session_bifrost(client, session_id, admin_key=admin_key)
+            # slice-6: the SDK's admin.* routes use the client's admin_auth (built with
-    except SessionApiFailed as exc:
+            # admin_key), not a per-call header — so it rides on the wt client here.
+            client = _wt_client(transport, admin_key=admin_key)
+            bstate = await wt.get_session_bifrost(client, session_id)
+    except wt.SessionApiFailed as exc:
         return JSONResponse(
             {"error_code": "bifrost_state_unavailable", "status": exc.status},
             status_code=exc.status,
         )
-    return JSONResponse(bstate, status_code=200)
+    except (httpx.RequestError, ConnectFailed) as exc:
+        # SDK normalizes a transport failure to ConnectFailed(status=0), not a raw
+        # httpx error; both surface the same network envelope (cutover foot-gun).
+        return JSONResponse(
+            {"error_code": "network_error", "message": str(exc)},
+            status_code=502,
+        )
+    return JSONResponse(dict(bstate), status_code=200)
 
 
 def _admin_event_matches_web(ev: AdminEvent, session_id: str | None) -> bool:
@@ -608,9 +626,13 @@ async def _admin_events_endpoint(request: Request) -> Response:
     client_factory = request.app.state.client_factory
 
     async def gen() -> AsyncIterator[bytes]:
-        client = client_factory()
+        transport = client_factory()
+        # slice-6: admin_auth rides on the wt client (built with admin_key); the adapter
+        # re-wraps the SDK's AdminEvent → ratatoskr's (id/type/data degraded) and the
+        # stream's terminal SDK errors (incl. ConnectFailed) → the Sse* types below.
+        client = _wt_client(transport, admin_key=admin_key)
         try:
-            async for ev in stream_admin_events(client, admin_key=admin_key):
+            async for ev in wt.stream_admin_events(client):
                 if not _admin_event_matches_web(ev, session_id):
                     continue
                 # Fixed SSE event name so the browser renders EVERY admin type
@@ -630,7 +652,9 @@ async def _admin_events_endpoint(request: Request) -> Response:
         except asyncio.CancelledError:
             raise  # browser disconnect — let the generator unwind
         finally:
-            await client.aclose()
+            # ratatoskr owns the transport lifecycle (INV-CUT-1); close the injected
+            # httpx client, never the wt client (which would no-op the transport anyway).
+            await transport.aclose()
 
     return StreamingResponse(gen(), media_type="text/event-stream")
 

src/ratatoskr/wt.py

@@ -60,6 +60,7 @@ from .sessions import (
     Tier3UserIdUnsupported,
 )
 from .sse_client import (
+    AdminEvent,
     AgentNotAvailable,
     CancelAlreadyCompleted,
     CancelFailed,
@@ -684,3 +685,66 @@ async def delete_character(
         return await client.characters.delete(character_id)
     except ApiError as exc:
         raise translate_error(exc) from exc
+
+
+# ── slice-6: admin (bifrost inspection + admin-events stream) adapter routes ──
+# The admin surface over `client.admin.*` — admin_auth-scoped (set via
+# `build_client(admin_key=...)`, NOT a per-call `Authorization` header). Both are
+# web-only. `get_session_bifrost` reads the open-world `BifrostInspection` verbatim
+# (any error → the `SessionApiFailed` default); `stream_admin_events` drives the
+# long-lived D2 admin-events SSE, re-wrapping the SDK's `AdminEvent` → ratatoskr's
+# (degrading the SDK's `admin_id`-nan / None `type`/`data` at the boundary so the web
+# filter never crashes) and re-wrapping the stream's terminal errors → ratatoskr's
+# `Sse*` types (INV-CUT-2 stream rows).
+
+
+async def get_session_bifrost(
+    client: WorldtreeClient, session_id: str
+) -> Mapping[str, Any]:
+    """The admin-scoped Bifrost dispatch state for a session (GET
+    /admin/sessions/{id}/bifrost, #176), open-world dict verbatim.
+
+    Admin-tier — the client MUST carry `admin_auth` (built with `admin_key`); the SDK
+    uses that provider, not a per-call header. Any error → the `SessionApiFailed`
+    default (notably 403 `auth_scope_denied`, 404 `session_not_bifrost_bound`) — the
+    retired hand-rolled path likewise mapped every non-200 generically.
+    """
+    assert session_id and isinstance(session_id, str)
+    try:
+        return await client.admin.sessions.bifrost(session_id)
+    except ApiError as exc:
+        raise translate_error(exc) from exc
+
+
+async def stream_admin_events(
+    client: WorldtreeClient, *, last_event_id: int | None = None
+) -> AsyncGenerator[AdminEvent, None]:
+    """Drive the long-lived admin-events SSE (GET /admin/events, #11 / INV-046) and yield
+    ratatoskr `AdminEvent`s, re-wrapping the SDK's typed `AdminEvent` at the boundary.
+
+    Admin-tier (the client MUST carry `admin_auth`). The SDK's `AdminEvent` is open-world
+    where ratatoskr's is stable: `admin_id` is `nan` for an id-less envelope (→ `id=0`),
+    and `type`/`data` may be None (→ `""` / `{}`) — normalized HERE so the web filter +
+    formatter (`ev.id` / `ev.type` / `ev.data`) never crash on a partial wire (chosen over
+    yielding SDK events through + rewiring the web filter). Error map (INV-CUT-2, stream
+    rows): SDK `ApiError` (a non-200 open — the admin stream raises `admin_stream_failed`,
+    NOT `ConnectFailed`) → `SseConnectFailed`; SDK `ConnectionDropped` (a connect-time
+    transport failure → cursor None, OR a mid-stream drop / the long-lived stream's
+    resumable EOF → cursor) → `SseConnectionDropped`. The SDK stream is best-effort (skips
+    malformed frames — no `Malformed*`).
+    """
+    try:
+        async for ev in client.admin.stream_events(last_event_id=last_event_id):
+            yield AdminEvent(
+                id=ev.admin_id if isinstance(ev.admin_id, int) else 0,
+                type=ev.type or "",
+                timestamp=ev.timestamp,
+                data=dict(ev.data) if isinstance(ev.data, Mapping) else {},
+            )
+    except wtsdk.ConnectionDropped as exc:
+        raise SseConnectionDropped(last_seen_sse_id=exc.last_seen_sse_id) from exc
+    except ApiError as exc:
+        # The admin stream raises ApiError("admin_stream_failed", status=…) on a non-200
+        # open (a connect-time transport failure instead surfaces as ConnectionDropped);
+        # map the non-200 → SseConnectFailed so the web's stream-error handler catches it.
+        raise SseConnectFailed(status=exc.status, body=(exc.body or "").encode()) from exc

tests/test_sessions.py

@@ -1,14 +1,13 @@
-"""Tests for ratatoskr.sessions per docs/contracts/issues/2.contract.md."""
+"""Tests for ratatoskr.sessions per docs/contracts/issues/2.contract.md.
+
+Post worldtree-sdk cutover the `sessions` module is down to `endpoint_for_plane`
+(the Bifrost provider-plane helper) + the caller-semantic exception classes the
+`ratatoskr.wt` adapter raises; every wire wrapper has retired onto the SDK adapter
+(the wrappers' tests live in `test_wt.py`)."""
 
-import httpx
 import pytest
-import respx
 
-from ratatoskr.sessions import (
+from ratatoskr.sessions import endpoint_for_plane
-    SessionApiFailed,
-    endpoint_for_plane,
-    get_session_bifrost,
-)
 
 
 class TestEndpointForPlane:
@@ -30,65 +29,3 @@ class TestEndpointForPlane:
         """unknown_plane [adversarial]: any other plane → ValueError (PRE-001)."""
         with pytest.raises(ValueError):
             endpoint_for_plane("persona", "10.100.10.50")
-
-
-class TestGetSessionBifrost:
-    """#2 contract — get_session_bifrost (GET /admin/sessions/{id}/bifrost, #176)."""
-
-    @respx.mock
-    async def test_happy_uses_admin_bearer(self) -> None:
-        """happy [happy,tracer]: 200 → binding dict; request carries the ADMIN bearer (override)."""
-        route = respx.get("https://w.example/admin/sessions/s1/bifrost").mock(
-            return_value=httpx.Response(
-                200,
-                json={
-                    "endpoint_url": "https://bifrost.example/mcp",
-                    "consumer_id": "alice",
-                    "connected": True,
-                    "capabilities_granted": ["tools:call", "tools:read"],
-                    "tools": [{"name": "bifrost.alice.echo", "description": "echo"}],
-                },
-            )
-        )
-        async with httpx.AsyncClient(
-            base_url="https://w.example",
-            headers={"Authorization": "Bearer consumer-key"},
-        ) as client:
-            state = await get_session_bifrost(client, "s1", admin_key="admin-xyz")
-        assert state["connected"] is True
-        assert state["tools"][0]["name"] == "bifrost.alice.echo"
-        # the request overrode the client's default consumer bearer with the admin key
-        assert route.calls[0].request.headers["Authorization"] == "Bearer admin-xyz"
-
-    @respx.mock
-    async def test_403_scope_denied(self) -> None:
-        """403 [error]: admin key lacks admin.sessions.read → SessionApiFailed(403)."""
-        respx.get("https://w.example/admin/sessions/s1/bifrost").mock(
-            return_value=httpx.Response(403, json={"error_code": "auth_scope_denied"})
-        )
-        async with httpx.AsyncClient(base_url="https://w.example") as client:
-            with pytest.raises(SessionApiFailed) as exc:
-                await get_session_bifrost(client, "s1", admin_key="k")
-        assert exc.value.status == 403
-
-    @respx.mock
-    async def test_404_not_bound(self) -> None:
-        """404 [error]: session_not_bifrost_bound → SessionApiFailed(404)."""
-        respx.get("https://w.example/admin/sessions/s1/bifrost").mock(
-            return_value=httpx.Response(404, json={"error_code": "session_not_bifrost_bound"})
-        )
-        async with httpx.AsyncClient(base_url="https://w.example") as client:
-            with pytest.raises(SessionApiFailed) as exc:
-                await get_session_bifrost(client, "s1", admin_key="k")
-        assert exc.value.status == 404
-
-    @respx.mock
-    async def test_empty_admin_key_asserts(self) -> None:
-        """empty_admin_key [adversarial]: '' → AssertionError; no HTTP issued."""
-        route = respx.get("https://w.example/admin/sessions/s1/bifrost").mock(
-            return_value=httpx.Response(200, json={})
-        )
-        async with httpx.AsyncClient(base_url="https://w.example") as client:
-            with pytest.raises(AssertionError):
-                await get_session_bifrost(client, "s1", admin_key="")
-        assert route.call_count == 0

tests/test_sse_client.py

@@ -1,94 +0,0 @@
-"""Tests for ratatoskr.sse_client — the admin-events stream (#11).
-
-The turn-stream + Event-model tests retired with the worldtree-sdk cutover (#20);
-the turn path is now covered by tests/test_wt.py + the CLI/web integration tests.
-This module keeps the still-hand-rolled admin-events surface (slice-6)."""
-
-import httpx
-import pytest
-import respx
-
-from ratatoskr.sse_client import (
-    AdminEvent,
-    SseConnectFailed,
-    stream_admin_events,
-)
-
-
-def _sse_chunk(sse_id: str, body: dict[str, object]) -> bytes:
-    """Compose one SSE event in wire format. Trailing blank line per spec."""
-    import json
-
-    return f"id: {sse_id}\ndata: {json.dumps(body)}\n\n".encode()
-
-
-class TestStreamAdminEvents:
-    """docs/conversation-api-spec.md § Admin Event Stream — stream_admin_events (#11)."""
-
-    @respx.mock
-    async def test_happy_multi_event_admin_bearer(self) -> None:
-        """happy [happy,tracer]: yields AdminEvent envelopes; request uses the ADMIN bearer."""
-        env1 = {
-            "id": 41, "type": "session.created", "timestamp": "2026-05-06T10:00:00.000Z",
-            "data": {"session_id": "s1", "agent_id": "mimir", "user_id": None},
-        }
-        env2 = {
-            "id": 42, "type": "turn.started", "timestamp": "2026-05-06T10:00:01.000Z",
-            "data": {"session_id": "s1", "turn_id": 7, "agent_id": "mimir", "user_id": None},
-        }
-        stream = _sse_chunk("41", env1) + _sse_chunk("42", env2)
-        route = respx.get("https://w.example/admin/events").mock(
-            return_value=httpx.Response(
-                200, headers={"content-type": "text/event-stream"}, content=stream
-            )
-        )
-        async with httpx.AsyncClient(
-            base_url="https://w.example", headers={"Authorization": "Bearer consumer"}
-        ) as client:
-            events = [e async for e in stream_admin_events(client, admin_key="admin-xyz")]
-        assert [e.type for e in events] == ["session.created", "turn.started"]
-        assert isinstance(events[0], AdminEvent)
-        assert events[0].id == 41
-        assert events[1].data["turn_id"] == 7
-        assert route.calls[0].request.headers["Authorization"] == "Bearer admin-xyz"
-
-    @respx.mock
-    async def test_last_event_id_header(self) -> None:
-        """last_event_id_header [trace]: empty stream → []; Last-Event-ID header sent."""
-        route = respx.get("https://w.example/admin/events").mock(
-            return_value=httpx.Response(
-                200, headers={"content-type": "text/event-stream"}, content=b""
-            )
-        )
-        async with httpx.AsyncClient(base_url="https://w.example") as client:
-            events = [e async for e in stream_admin_events(client, admin_key="k", last_event_id=99)]
-        assert events == []
-        assert route.calls[0].request.headers["Last-Event-ID"] == "99"
-
-    @respx.mock
-    async def test_403_scope_denied(self) -> None:
-        """403 [error]: key lacks admin.events.read → SseConnectFailed(403)."""
-        respx.get("https://w.example/admin/events").mock(
-            return_value=httpx.Response(403, json={"error_code": "auth_scope_denied"})
-        )
-        async with httpx.AsyncClient(base_url="https://w.example") as client:
-            with pytest.raises(SseConnectFailed) as exc:
-                _ = [e async for e in stream_admin_events(client, admin_key="k")]
-        assert exc.value.status == 403
-
-    @respx.mock
-    async def test_skips_malformed_frame(self) -> None:
-        """skips_malformed [adversarial]: a bad-JSON frame is skipped, not fatal."""
-        good = _sse_chunk("41", {"id": 41, "type": "session.created", "data": {"session_id": "s1"}})
-        bad = b"id: 42\ndata: not-json\n\n"
-        good2 = _sse_chunk(
-            "43", {"id": 43, "type": "session.deleted", "data": {"session_id": "s1"}}
-        )
-        respx.get("https://w.example/admin/events").mock(
-            return_value=httpx.Response(
-                200, headers={"content-type": "text/event-stream"}, content=good + bad + good2
-            )
-        )
-        async with httpx.AsyncClient(base_url="https://w.example") as client:
-            events = [e async for e in stream_admin_events(client, admin_key="k")]
-        assert [e.type for e in events] == ["session.created", "session.deleted"]

tests/test_wt.py

@@ -38,6 +38,7 @@ from ratatoskr.sessions import (
     Tier3UserIdUnsupported,
 )
 from ratatoskr.sse_client import (
+    AdminEvent,
     AgentNotAvailable,
     CancelAlreadyCompleted,
     CancelFailed,
@@ -62,6 +63,7 @@ from ratatoskr.wt import (
     get_character_state,
     get_me,
     get_persona_state,
+    get_session_bifrost,
     get_session_messages,
     get_session_tools,
     list_agents,
@@ -69,6 +71,7 @@ from ratatoskr.wt import (
     list_sessions,
     patch_agent,
     set_persona_state,
+    stream_admin_events,
     stream_turn,
     translate_error,
     write_authored_history,
@@ -1066,3 +1069,153 @@ class TestDeleteCharacter:
         with pytest.raises(SessionApiFailed) as ei:
             await delete_character(_wtm(fake), "char_x")
         assert ei.value.status == 500
+
+
+# ── slice-6: admin (bifrost inspection + admin-events stream) adapter routes ──
+
+
+class _SdkAdminEvent:
+    """Minimal stand-in for the SDK's `AdminEvent` — the adapter reads
+    `admin_id`/`type`/`timestamp`/`data`. `admin_id` may be `nan` (id-less);
+    `type`/`data` may be None (open-world)."""
+
+    def __init__(self, admin_id: Any, type: Any, timestamp: Any = None, data: Any = None) -> None:
+        self.admin_id = admin_id
+        self.type = type
+        self.timestamp = timestamp
+        self.data = data
+
+
+class _FakeAdminSessions:
+    def __init__(self, admin: _FakeAdmin) -> None:
+        self._admin = admin
+
+    async def bifrost(self, *a: Any, **k: Any) -> Any:
+        return await self._admin._bifrost(*a, **k)
+
+
+class _FakeAdmin:
+    """Stand-in for `client.admin` — `.sessions.bifrost(id)` (canned result/error) +
+    `.stream_events(...)` (canned events / terminal error). Same shape as `_FakeSessions`."""
+
+    def __init__(
+        self,
+        *,
+        result: Any = None,
+        error: BaseException | None = None,
+        events: list[Any] | None = None,
+        stream_error: BaseException | None = None,
+    ) -> None:
+        self._result = result
+        self._error = error
+        self._events = events or []
+        self._stream_error = stream_error
+        self.calls: list[tuple[str, tuple[Any, ...], dict[str, Any]]] = []
+        self.sessions = _FakeAdminSessions(self)
+
+    async def _bifrost(self, *a: Any, **k: Any) -> Any:
+        self.calls.append(("bifrost", a, k))
+        if self._error is not None:
+            raise self._error
+        return self._result
+
+    def stream_events(self, *a: Any, **k: Any) -> Any:
+        self.calls.append(("stream_events", a, k))
+        return self._astream()
+
+    async def _astream(self) -> Any:
+        for ev in self._events:
+            yield ev
+        if self._stream_error is not None:
+            raise self._stream_error
+
+
+class _FakeAdminClient:
+    def __init__(self, admin: _FakeAdmin) -> None:
+        self.admin = admin
+
+
+def _wtad(admin: _FakeAdmin) -> WorldtreeClient:
+    """Cast the admin-surface fake (`.admin.sessions.bifrost` + `.admin.stream_events`)
+    to the nominal client type the slice-6 route functions are typed against."""
+    return cast(WorldtreeClient, _FakeAdminClient(admin))
+
+
+class TestGetSessionBifrostWt:
+    """slice-6: get_session_bifrost → SDK admin.sessions.bifrost(id); open-world verbatim."""
+
+    async def test_happy_returns_dict_verbatim(self) -> None:
+        binding = {"endpoint_url": "https://b/mcp", "connected": True, "tools": []}
+        fake = _FakeAdmin(result=binding)
+        out = await get_session_bifrost(_wtad(fake), "s1")
+        assert out is binding
+        assert fake.calls[-1] == ("bifrost", ("s1",), {})
+
+    async def test_empty_id_asserts_no_call(self) -> None:
+        fake = _FakeAdmin(result={})
+        with pytest.raises(AssertionError):
+            await get_session_bifrost(_wtad(fake), "")
+        assert fake.calls == []
+
+    async def test_403_maps_to_session_api_failed(self) -> None:
+        fake = _FakeAdmin(error=ApiError("auth_scope_denied", "no", status=403))
+        with pytest.raises(SessionApiFailed) as ei:
+            await get_session_bifrost(_wtad(fake), "s1")
+        assert ei.value.status == 403
+
+    async def test_404_not_bound_maps_to_session_api_failed(self) -> None:
+        fake = _FakeAdmin(error=ApiError("session_not_bifrost_bound", "no", status=404))
+        with pytest.raises(SessionApiFailed) as ei:
+            await get_session_bifrost(_wtad(fake), "s1")
+        assert ei.value.status == 404
+
+
+class TestStreamAdminEventsWt:
+    """slice-6: stream_admin_events → SDK admin.stream_events; re-wrap SDK AdminEvent →
+    ratatoskr AdminEvent (nan/None degraded), terminal errors → Sse* types."""
+
+    async def test_rewraps_events_to_ratatoskr_shape(self) -> None:
+        sdk_evs = [
+            _SdkAdminEvent(5, "session.created", "t0", {"session_id": "s1"}),
+            _SdkAdminEvent(6, "turn.completed", "t1", {"session_id": "s1", "turn_id": 2}),
+        ]
+        fake = _FakeAdmin(events=sdk_evs)
+        out = await _drain(stream_admin_events(_wtad(fake)))
+        assert all(isinstance(e, AdminEvent) for e in out)
+        assert (out[0].id, out[0].type, out[0].timestamp) == (5, "session.created", "t0")
+        assert out[0].data == {"session_id": "s1"}
+        assert out[1].id == 6
+
+    async def test_nan_admin_id_degrades_to_zero(self) -> None:
+        fake = _FakeAdmin(events=[_SdkAdminEvent(float("nan"), "system.heartbeat", None, None)])
+        out = await _drain(stream_admin_events(_wtad(fake)))
+        assert out[0].id == 0  # id-less envelope → 0, not nan
+
+    async def test_none_type_and_data_degrade(self) -> None:
+        # A partial wire: type=None (would crash `.startswith` in the web filter) and
+        # data=None (would crash `.get`) → "" and {} at the adapter boundary.
+        fake = _FakeAdmin(events=[_SdkAdminEvent(1, None, None, None)])
+        out = await _drain(stream_admin_events(_wtad(fake)))
+        assert out[0].type == ""
+        assert out[0].data == {}
+
+    async def test_passes_last_event_id(self) -> None:
+        fake = _FakeAdmin(events=[])
+        await _drain(stream_admin_events(_wtad(fake), last_event_id=42))
+        assert fake.calls[-1] == ("stream_events", (), {"last_event_id": 42})
+
+    async def test_non_200_apierror_maps_to_sse_connect_failed(self) -> None:
+        # The SDK admin stream raises ApiError("admin_stream_failed", status=…) on a
+        # non-200 open (NOT ConnectFailed) — mapped → SseConnectFailed for the web.
+        fake = _FakeAdmin(stream_error=ApiError("admin_stream_failed", "no", status=502))
+        with pytest.raises(SseConnectFailed) as ei:
+            await _drain(stream_admin_events(_wtad(fake)))
+        assert ei.value.status == 502
+
+    async def test_connection_dropped_maps_and_carries_cursor(self) -> None:
+        # Both a connect-time failure (cursor None) and a mid-stream drop / resumable
+        # EOF (cursor set) surface as ConnectionDropped → SseConnectionDropped.
+        fake = _FakeAdmin(stream_error=wtsdk.ConnectionDropped("42"))
+        with pytest.raises(SseConnectionDropped) as ei:
+            await _drain(stream_admin_events(_wtad(fake)))
+        assert ei.value.last_seen_sse_id == "42"

uv.lock

@@ -472,7 +472,7 @@ wheels = [
 
 [[package]]
 name = "ratatoskr"
-version = "0.21.18"
+version = "0.21.19"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },