ADR-004: composable reins as middleware stays deferred (GLAS-WP-0002-T01)

Checked ADR-002 part 2's deferred question against the two observability
additions that landed since (rein-aharness's tool-event stream,
glas-harness's own gateway hub event) -- both turned out simpler as
direct implementations, neither needed a wrapping middleware layer.
Still zero real candidates for that shape. docs/harness-contract.md
gains the Middleware ABC as a documented, unimplemented sketch for if a
real third case ever appears -- no code written now.

Also flagged GLAS-WP-0002-T02 (live OpenBao verification) as blocked:
`bao token lookup` from this workstation returns 403, no usable vault
session to provision a new AppRole with. Needs the operator.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

WORK-RECORDS.md

@@ -22,5 +22,5 @@
 | task | GLAS-WP-0001-T06 | done | — | workplans/GLAS-WP-0001-harness-router-foundation.md |
 | task | GLAS-WP-0002-T01 | todo | — | workplans/GLAS-WP-0002-observability-and-composability-followups.md |
 | task | GLAS-WP-0002-T02 | todo | — | workplans/GLAS-WP-0002-observability-and-composability-followups.md |
-| task | GLAS-WP-0002-T03 | todo | — | workplans/GLAS-WP-0002-observability-and-composability-followups.md |
+| task | GLAS-WP-0002-T03 | done | — | workplans/GLAS-WP-0002-observability-and-composability-followups.md |
 | task | GLAS-WP-0002-T04 | todo | — | workplans/GLAS-WP-0002-observability-and-composability-followups.md |

docs/adr/ADR-002-credential-brokering-and-composable-reins.md

@@ -75,7 +75,13 @@ repeats the same need — decide from evidence, not in advance.
 - `GLAS-WP-0001-T06` is done. `GLAS-WP-0001-T05` (bootstrap
   `rein-openweights`) is unblocked.
 
-## Part 2 — open, deferred: composable reins as middleware
+## Part 2 — resolved in ADR-004: composable reins stay deferred
+
+See `docs/adr/ADR-004-composable-reins-stay-deferred.md` — the deferral
+below held even after two more observability additions landed; both
+turned out simpler as direct implementations, not middleware.
+
+## Part 2 (original framing, for context)
 
 Separately, the idea surfaced that monitoring/evaluation/optimization
 (capabilities `llm-connect` already stages as optional Functional

docs/adr/ADR-004-composable-reins-stay-deferred.md

@@ -0,0 +1,67 @@
+# ADR-004: Composable reins as middleware — stay deferred
+
+- Status: accepted
+- Date: 2026-07-26
+- Deciders: Bernd Worsch
+
+## Context
+
+`ADR-002` part 2 raised the idea, left deliberately open: could
+monitoring/evaluation/optimization become their own composable reins —
+middleware wrapping or observing a base rein's `dispatch_tool` calls,
+rather than each being a complete alternative harness backend? At the
+time there was exactly one candidate capability to generalize from
+(llm-connect's optional Functional-layer modules: diagnostics, replay,
+budget tracking), and the rule set then was: don't build the abstraction
+until a second real candidate shows up.
+
+Since then, two more observability additions landed:
+
+1. `rein-aharness`'s per-tool-call audit stream
+   (`HARNESS-WP-0002-T03`) — `AgenticClaudeCodeAdapter` gained an
+   `on_tool_event` callback, parsing `claude`'s `stream-json` output.
+2. `glas-harness`'s own gateway hub event (`GLAS-WP-0002-T03`) —
+   `run_task_through_rein` posts a `gateway_run` progress event under
+   its own actor attribution, independent of whatever the rein reports.
+
+Both are exactly the *kind* of thing the middleware idea was reaching
+for: cross-cutting observability layered on top of a rein's tool
+dispatch. Worth checking, now that two real examples exist, whether they
+should have been built as `Middleware` wrapping a `Rein`, per the sketch
+in `docs/harness-contract.md`.
+
+## Decision
+
+**They shouldn't have been, and composable-reins-as-middleware stays
+deferred — sketch recorded, no code.**
+
+Both additions turned out to be simpler as direct implementations than a
+wrapping-middleware abstraction would have been:
+
+- Item 1 lives *inside* `rein-aharness`'s own adapter, because the thing
+  being observed (Claude Code's internal tool execution) is only visible
+  from inside that adapter's process boundary in the first place — no
+  external wrapper could intercept it, wrapping-middleware or otherwise.
+- Item 2 lives in `glas-harness`'s own gateway, because it's reporting on
+  the gateway's *own* actions (sandbox lifecycle, dispatch call), not
+  wrapping a rein's internals — there's nothing here a `Middleware`
+  layer would add over just... doing it in the gateway.
+
+Neither is evidence for the original idea (a rein-shaped monitoring/eval/
+optimization layer sitting *between* glas-harness and a base rein). The
+original candidate — llm-connect's optional modules — remains untouched
+and unintegrated into either rein. Two additions still isn't two
+candidates for *this specific shape*; it's zero candidates plus two
+observations that the direct-implementation path keeps winning on its
+own merits.
+
+## Consequences
+
+- `docs/harness-contract.md` keeps the `Middleware` ABC as a documented,
+  unimplemented sketch — reachable if a real third case appears, not
+  built speculatively.
+- `GLAS-WP-0002-T01` closes on this ADR; no code follows from it.
+- Future observability needs should default to "implement directly where
+  the data actually is" (as both examples here did) unless a genuine
+  cross-rein reuse case forces the composition question — don't reach
+  for `Middleware` reflexively just because it's now documented.

docs/harness-contract.md

@@ -74,13 +74,51 @@ Every `dispatch_tool` call and lifecycle transition carries an actor
 glas-harness stamps this at dispatch time; reins do not need their own
 actor model.
 
+## Composable reins as middleware (deferred — sketch only, no code)
+
+`docs/adr/ADR-002-credential-brokering-and-composable-reins.md` part 2
+raised whether monitoring/evaluation/optimization should become their
+own composable reins — middleware that wraps or observes a base rein's
+`dispatch_tool` calls, rather than each being a complete alternative
+harness backend the way `rein-aharness`/`rein-openweights` are. Resolved
+in `docs/adr/ADR-004-composable-reins-stay-deferred.md`: **still
+deferred, sketch recorded, no code written.** The two observability
+additions since (rein-aharness's per-tool-call audit stream,
+`glas-harness`'s own gateway hub event) both turned out to be simpler as
+direct implementations — neither needed a separate wrapping rein — so
+there still isn't a second real capability wanting this shape, only the
+original one (llm-connect's optional Functional-layer modules,
+untouched).
+
+If a real second candidate appears, the shape would be:
+
+```python
+class Middleware(ABC):
+    """Wraps another Rein's dispatch_tool, does not replace start_session/end_session."""
+
+    def __init__(self, inner: Rein) -> None:
+        self.inner = inner
+
+    @abstractmethod
+    def dispatch_tool(self, session: dict[str, str], tool_call: ToolCall) -> ToolResult:
+        """Call self.inner.dispatch_tool(...), observe/transform, return the result."""
+
+    def start_session(self, profile, inputs, sandbox) -> dict[str, str]:
+        return self.inner.start_session(profile, inputs, sandbox)
+
+    def end_session(self, session) -> dict[str, str]:
+        return self.inner.end_session(session)
+```
+
+A chain of `Middleware` wrapping a base `Rein` still satisfies the `Rein`
+ABC itself (composition, not a parallel type), so glas-harness's gateway
+would not need to change to consume one — this is deliberately *not* a
+speculative gateway-side change, just a documented shape to reach for
+if/when a second candidate shows up.
+
 ## Open questions this contract does not resolve yet
 
-- Whether `start_session` also carries scheduling/blueprint-sourcing
-  parameters (kaizen-agentic blueprint id, activity-core task id) as part
-  of `inputs`, or whether that stays entirely rein-side — tracked in
-  `rein-aharness/workplans/HARNESS-WP-0002-T04`.
-- The exact `SandboxHandle`/`ToolCall`/`ToolResult` field shapes — sketched
-  here at the level needed to unblock `GLAS-WP-0001-T04` (the
-  rein-aharness parity proof); refine once that task is underway rather
-  than speculatively now.
+- The exact `SandboxHandle`/`ToolCall`/`ToolResult` field shapes — these
+  have stabilized in practice (both reins implement them identically)
+  but are not yet declared frozen/versioned the way sand-boxer's models
+  are.

workplans/GLAS-WP-0002-observability-and-composability-followups.md

@@ -30,9 +30,18 @@ record the decision as an ADR addendum, and only write code if a real
 middleware candidate (e.g. a monitoring rein) is scoped alongside it in
 this same task — not before.
 
+**Done (2026-07-26), stays deferred.** `docs/adr/ADR-004-composable-reins-stay-deferred.md`
+checked this against the two observability additions that landed since
+ADR-002 (rein-aharness's tool-event stream, glas-harness's own gateway
+hub event, both `HARNESS-WP-0002-T03`/`GLAS-WP-0002-T03`) — both turned
+out simpler as direct implementations, neither needed a wrapping
+middleware layer. Still zero real candidates for *this* shape, so no
+code written. `docs/harness-contract.md` now carries the `Middleware`
+ABC sketch for future reference, explicitly marked don't-build-yet.
+
 ```task
 id: GLAS-WP-0002-T01
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "2de6074e-b72b-4eb7-b454-6b849011348c"
 ```
@@ -51,9 +60,17 @@ vault round trip actually works end to end. Coordinate with
 `rein-openweights` directly; this task's outcome should be recorded in
 both repos.
 
+**Blocked (checked 2026-07-26):** `bao token lookup` from this
+workstation returns `403 permission denied` — no usable vault session
+here. Provisioning a new AppRole (`auth/approle/role/...`) and a KV
+secret for `rein-openweights`, mirroring `rein-aharness`'s `binky-mail`
+lane, needs vault-admin access this session doesn't have. Needs the
+operator to provision the AppRole (or provide an ambient token with
+enough privilege) before this can be exercised for real.
+
 ```task
 id: GLAS-WP-0002-T02
-status: todo
+status: wait
 priority: medium
 state_hub_task_id: "74b4f35b-9cdd-4228-aeed-e0eec458c0bf"
 ```