Deploy the adapter fix and document the four outcomes

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

adapter/README.md

@@ -42,3 +42,22 @@ completed task is the wrong shape for "a human has to look at this".
 
 One skill per instance, deliberately. A second one is a card change, which is
 the moment to ask whether the agent has quietly become a data proxy.
+
+## Four outcomes, and only one of them completes
+
+HTTP 200 from n8n does not mean the workflow answered. It returns 200 with an
+**empty body** when a node throws before the Respond node runs — a refused token
+exchange is the common way in. The adapter used to read that as a completed task
+carrying "(the workflow returned nothing)", which told the caller the task had
+succeeded: the one thing certainly false.
+
+| `Outcome` | A2A task state |
+|---|---|
+| `ANSWERED` — the contract, `escalate: false` | `completed` |
+| `ESCALATED` — the contract, `escalate: true` | `failed` |
+| `SILENT` — 200 with an empty body | `failed` |
+| `OFF_CONTRACT` — a body that is not `{"answer", "escalate"}` | `failed` |
+
+Off contract is returned **raw** so a workflow that has drifted is visible — but
+never as agreement. Escalation is `failed` for the older reason: an autonomous
+agent meeting a rule that needs approval must fail cleanly, never decide.